Microcystic adnexal carcinoma: a light microscopic, immunohistoehemical and ultrastructural study We report a case of microcystic adnexal carcinoma (MAC) occurring on the upper lip of an 82-year-old woman. Microscopically the tumor showed both pilar and sweat gland differentiation, involved the entire dermis and subcutaneous tissue, and invaded perineural spaces. Immunoperoxidase studies revealed carcinoembrionic antigen to be present in the ductal lining cells and in the amorphous content in the lumen, confirming sweat gland differentiation. The S-100 protein was positive in dendritic cells within the solid cell nests, but negative in cells lining cystic spaces. Ultrastructural study confirmed that the neoplasm was composed of two components, with pilar and eccrine differentiation. The former showed concentric layers of squamous epithelial cells with well-developed desmosomes and cytofilaments. The latter had ductal and alveolar structures; the ultrastructural features included i) numerous villous folds of plasma membrane to interdigitate each other by focal desmosomes, ii) aggregates of cytofilaments, and iii) basally located myoepithelial cells which were separated from the surrounding stroma by rather thick basement membrane. In addition, distinct amyloid deposition was also observed on ultrastructural examination. To our knowledge, amyloid deposition has not been previously reported in MAC.
Haruhisa Kato, Nobuyuki Mizuno, Koichi Nakagawa, Masayoski Furukawa, Toshio Hamada
Kato H, Mizuno N, Nakagawa K, Furukawa M, Hamada T. Microcystic adnexal carcinoma: a light microscopic, immunohistoehemical and ultrastructural study. J Cutan Pathol 1990: 17: 87-95.
Haruhisa Kato, Department of Dermatology, Osaka City University Medical School, 1-5-7, Asahimachi, Abeno-ku, Osaka 545, Japan
There have been many reports and studies of microcystic adnexal carcinoma (MAC) since Goldstein et al. (1) first described 6 cases in 1982. Clinically, the neoplasm is locally aggressive, and tends to recur despite local excision. Histopathologically, it seldom shows cellular atypia and mitosis, and exhibits both follicular and sweat gland differentation (2, 3). One of the most characteristic microscopic features is multiple nests and strands of squamous or basaloid cells, forming keratin-filled cysts (1-8). Some pathologists prefer the term malignant syringoma (9), or sweat gland carcinoma with syringomatous features (10) to MAC; and the term sclerosing sweat duct (syringomatous) carcinoma was used by Cooper et al. (2, 11). Ultrastructural featues of MAC have not been thoroughly investigated. Only a few of the reported
Department of Dermatology, Osaka City University Medical School, Japan
Accepted September 18, 1989
studies have included any ultrastructural description (8, 10). We report MAC in which amyloid deposition was observed, and discuss the light and electron microscopic features of the disease.
Case report
In 1987, an 82-year-old woman was admitted to the Osaka City University Hospital for evaluation of a lesion present for 10 years on the right nasolabial area. The lesion had gradually increased in size and, become ulcerated and friable. The patient denied having pain, paresthesia, or anesthesia in the area of involvement. There was no history of previous radiotherapy to the face. At the time of admission, there was an ulcerated, indurated lesion with a 87
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gen (CEA) (DAKO PAP kit), and S-100 protein (DAKO PAP kit). For electron microscopic examinations, specimens were cut into about 1 X 1 X 4 mm cubes and fixed at 4°C, in 2.5% gluteraldehyde buffered with 0.1 M phosphate buffer (pH 7.4) for 1 h and post-fixed with 1% osmium tetroxide in 0.1 M phosphate buffer (pH 7.4) for 2 h. Routine methods were used for embedding, thin sectioning and staining. The sections were examined with a Hitachi H-300 electron microscope. Results Light microscopy
Fig. I. Light photomicrograph of microcystic adnexal carcinoma. Upper and middermis infiltrated by keiatinous cysts and onionlike globes, surrounding non-neoplastic pilosebaceous follicles (H&E, X30).
smooth, shiny surface and small telangiectases. The lesion involved the right nasolabial area, nasal ala and the upper right lip, and measured 2.0 X 2.8 cm. There was no cervical lymphadenopathy, other skin tumor or neurological deficit. The clinical impression was morphea-like basal cell epithelioma, and the patient underwent a wide resection, with a margin of 0.5 cm from the border of the tumor. The right nasal ala was removed. The lesion grossly extended into the underlying mucosa. Material and methods
The surgical specimens were processed for light microscopic, immunohistoehemical and electron microscopic studies. For light microscopic examinations, formalin-fixed, paraffin-embedded specimens were cut at 7 |im, and stained with H&E and Dylon (12). For immunoperoxidase study, the parafTin-embedded specimens were sectioned 7-|xmthick, and examined using the peroxidase-antiperoxidase (PAP) technique for carcinoembrionic anti88
Histological examination showed the tumor contained 2 components (Fig. 1). The first component comprised small solid nests and strands of tumor cells irregularly distributed throughout the dermis. In addition, a large number of ductal structures of varying size and shape were seen (Fig. 2). The cells comprising these cell nests, strands and lining of ductal structures were cuboid to round with a moderate to abundant amount of eosinophilic cytoplasm. Their nuclei were small and hyperchromatic. Some contained amorphous eosinophilic material within the lumen. Cytologic atypicality was mild or lacking, and mitotic figures were absent. The second component was composed of small keratinous cysts lined by squamous epithelium (Fig. 3). The keratinous cysts were largest and most numerous in the superficial dermis. They were rounded or oval, lined by a two-cell layer. They sometimes had one or more buds or elongated tadpole-like appendages. They contained dense, laminated keratin with focal calcification. There were groups of polygonal or cuboid cells with small, hyperchromatic nuclei and abundant clear cytoplasm, adjacent to the keratinized cysts (Fig. 4). In the upper dermis, connections between the tumor cells and the epidermis or adnexa were seen in some areas. In the middle and lower dermis, cystic structures were smaller, and small ductal structures were more numerous in the lower dermis. These were often much smaller and were associated with a dense hyalinized, collagenous stroma. Invasion to the subcutaneous tissue and perineural spaces was noted in some areas. Distinct amyloid deposits were demonstrated by Dylon staining (12) (Fig. 10). The amyloid material stained a bright orange color with Dylon, and was located within the collagenous stroma around the keratinous cysts. Immunohistochemistry
Immunohistoehemical staining using the peroxidase-antiperoxidase (PAP) technique for carcinoembrionic antigen (CEA) was focally positive on
Microcystic miuruuysiib adnexal auiicxiii carcinoma caruinuma
Fj^. 2. In the lower dermis, well-developed, tubulo-alveolar ductal structures, embedded in dense, fibrous tissue. Some contained amorphous eosinophilic materials within the lumen (H&E, X 125). - Fig. 3. Keratinous cysts lined by squamous epithelium separated by concentric bands of moderately cellular fibrous tissue. Some of them contained calcified keratin material (H&E, X60). - Fig. 4. Groups of polygonal or cuboid cells with small, hyperchromatic nuclei and abundant pale-staining cytoplasms (H&E, X\25).-Fig. 5. Amyloid deposits (arrowheads) are seen within the collagenous stroma (Dylon, X300). - Fig. 6. Immunoperoxidase staining for carcinoembrionic antigen: it is focally positive on the dilated ducts (diaminobenzidine & hematoxylin, X 125). -Ff^. 7. Immunoperoxidase staining with anti-S-100 protein antibody. Larger solid cell nests, showing positive staining in the dendritic cells (diaminobenzidine & hematoxylin, X125).
H. Kato et al. Fig. 8. Electron microscopic findings of MAC. Concentric layers of squamous epithelial cells forming a solid cell nest (uranyl acetate & lead citrate).
the ductal lining surface of tumor cells and in the amorphous contents within the lumen. CEA was seen focally in the contents of some keratinous cysts, however, no squamous epithelial cells were positively stained (Fig. 6). S-100 protein was negative in the ductal structures except for the cells located peripheral to the lining cells and the dendritic cells within the larger solid cell nests in the superficial dermis (Fig. 7).
Electron microscopy Electron microscopic examination showed concentric layers of epithelial cells with desmosomes and short cytoplasmic processes (Fig. 8). Most cells were spindle-shaped and interdigitated with each other by desmosomes, showing keratinization from peripheral layer toward the center of the nests. The epithelial cells had a number of filaments in their cytoplasm. Abrupt transition from nucleate to anucleate cells was accompanied by the loss of all cytoplasmic organelles. The keratinized cells were filled with abundant tonofilaments and retained their desmosomal connections (Fig. 9). Some contained electron-dense keratinous material at the center of the nests (Fig. 10). Numerous glycogen particles
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were distributed within the cytoplasm of both nonkeratinized and keratinized epithelial cells. The other type of cell nests and ductal structures showed glandular or ductal differentiation. The cells comprising the nests had a large, rounded or oval nucleus with one or no nucleolus. Within the cytoplasm of the cells there were numerous mitochondria and extensive rough-surfaced endoplasmic reticulum (Fig. 11). The most characteristic feature of the cells comprising small solid nests and ductal structures was the extensive plication of the plasma membrane to form long villous folds (Fig. 12). These interdigitated with similar folds of adjacent cells by desmosomes. Intercellular spaces were fairly extensive. Some of such cells had localized aggregations of microfilaments within the cytoplasm (Fig. 13). In other areas, cell-to-cell contact was made by closely interlocked villous folds of plasma membrane. Short, stumpy microvilli were seen along the luminal plasma membrane. The plasma membranes of apposed cells were studded with short desmosomes and tight junctions. Myoepithelial cells were located at the periphery of the cell nests, being separated from the surrounding stroma by basal lamina. These ultrastructural findings were indicative of glandular differentiation of the tumor.
Microcystic adnexal carcinoma
Ing 9 Ihc kcKitmous cells contained aggtegates of cytoplasmic filaments and numerous glycogen particles Cell-to-cell contact is made by desmosomes (uranyl acetate & lead citrate).
Close association of amyloid deposits with tumor cell nests was another peculiar finding of interest. Amyloid deposits were seen around the solid cell nests of follicular differentiation, and surrounded by the long cytoplasmic processes of fibroblasts. They were composed of straight, non-branching filaments 6-10 nm in diameter (Fig. 14).
Discussion Goldstein et al. (1) reported 6 patients with MAC in 1982, describing it as an unusual, highly locally aggressive adnexal neoplasm with a propensity for involving the upper lips of middle-aged women. Our patient was an elderly woman with a lesion involving the right nasal ala, nasolabial region and the upper lip, clinically resembling morphea-like basal cell epithelioma. Biopsies showed a variety of light microscopic patterns that in different areas suggested trichoepithelioma with horn cysts and syringoma. However, MAC differs from both syringoma and desmoplastic trichoepithelioma in its locally aggressive nature. Its histological appearances include keratinous cysts, abortive follicle-like struc-
tures embedded in a desmoplastic stroma, ducts and gland-like structures. Despite the infrequency of mitotic activity and cytologic atypia, MAC typically extends deep into skeletal muscle and invades perineural spaces. In this, it resembles eccrine gland carcinoma, but is distinguished by its benign cytologic appearance. Because of invasive growth, frequent recurrence, and both pilar and eccrine differentiation, the term microcystic adnexal carcinoma is preferred and signifies to the clinician an aggressive, infiltrating lesion (6). In our study, several fields were characterized by abundant horn cyst formation surrounded by keratinocytes, and some of them showed early calcification. These findings seemed to indicate pilar differentiation of the tumor. In other fields, ductal structures were seen lined by two layers of cuboid cells. The CEA immunohistoehemical results are identical to those previously reported by Nickoloff et al. (6) and Takemiya et al. (8). Nickoloff et al. (6) demonstrated CEA was present in the lumina of small ducts or on the ductal lining surface of the tumor cells and absent in the keratinous cysts. The
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Microcystic adnexal carcinoma Fig. JO. Some keratinous cysts undergo keratinization from peripheral layer toward the center of the nests, and contain electron-dense keratinous material (uranyl acetate & lead citrate). - Fig. IL A solid cell nest of eccrine differentiation. The cells comprising the nest have a large, rounded to oval nucleus and numerous mitochondria. Cell-to-cell contact is made by folded plasma membrane of opposing cells and focal desmosomes. BL: basal lamina, M: myoepithelial cell (uranyl acetate & lead citrate). - Fig. 12. Extensive plications of plasma membranes are seen in the cells showing ductal differentiation (uranyl acetate & lead citrate). - Fig. 13. On the luminal surface, there are numerous stumpy microvilli. Cell-to-cell contact is made by extensive plications of the plasma membranes and focal desmosomes. Aggregations of cytofilaments are seen (uranyl acetate & lead citrate).
positive immunoperoxidase staining for CEA in tumor tissue showing ductal formation is good evidence of sweat gland differentiation. CEA has been shown to be expressed in the skin by sweat glands and tumors arising therefrom (13, 14). Although the demonstration of CEA in a sweat gland neoplasm does not differentiate apocrine from eccrine-derived tumors, it may be helpful in separating tumors that arise from sweat gland epithelium from other adnexal tumors of pilar and sebaceous derivation (14). This notion is confirmed by the ultrastructural observation of eccrine sweat gland-like structures in the tumor tissue where secretory cells interlocked by folded plasma membranes and desmosomes, with basally located myoepithelial cells. The lack of CEA staining of the areas with the follicular appearance also supports the concept that this neoplasm combines differentiation toward both sweat gland and pilar structures. S-100 protein is an acidic, calciumbinding protein, and has been detected in normal skin and various skin tumors. In normal skin, S-100 protein is detected in the dendritic cells of epidermis (melanocytes and Langerhans cells), Schwann cells, and cells of the sweat gland apparatus (15). S-100 protein has been recently found in eccrine, but not in apocrine, sweat glands. Although initially believed to be present in myoepithelial cells (15), it seems that also eccrine clear secretory cells express this protein (16, 17). In the present case, S-100 protein was detected in the dendritic cells within the solid cell nests in the superficial dermis. Although they could not be demonstrated by electron microscopy, melanocytes or Langerhans cells are the most likely candidates for the dendritic cells situated in the solid cell nests. In fact, Takemiya et al. (8) demonstrated Langerhans cells within the epithelial cell nests of MAC by immunoperoxidase and ultrastructural examinations. Electron microscopic study also revealed that the tumor had two components, showing both pilar and eccrine differentiation. There have been few studies that included ultrastructural observations (8, 10). Electron microscopic examination was performed by Lipper and Peiper (10), and these findings resembled those described for normal eccrine ducts with ductal structures, luminal cells, microvilli and desmosomes, as seen in the present study. However, they did not refer to the ultrastructure of keratinous
cysts and solid cell nests. In syringoma and acrospiroma, the eccrine ducts may at times show significant keratinization with horn cyst formation and "follicular differentiation". It is still possible that keratinous cysts may show a peculiar form of keratinization, since trichohyaline granules were absent in the epithelial cells of the keratinous cysts. Immunostaining may play an important role in identifying the origin of the neoplastic cells. CEA is likely to be absent in purely squamous foci. The negative immunohistoehemical staining of CEA in the kerationous cysts is not suggestive of eccrine differentiation, but shows pilar differentiation. It is still unknown why MAC represents more than one direction of differentiation. Apisarnthanarax et al. (18) proposed the idea that pluripotential cells of the epidermis and cutaneous adnexa were capable of differentiating in more than one direction in a neoplalsm, since all of the cutaneous appendages arose from the embryonal epidermis. They proposed the term 'combined adnexal tumor of the skin' to denote such a neoplasm. Amyloid substance is sometimes encountered in many benign and malignant skin tumors of epithelial origin: basal cell epithelioma, actinic keratosis, Bowen's disease, seborrheic keratosis, calcifying epithelioma, cylindroma and Spitz nevus have all been known to contain amyloid (19, 20). Amyloid in these tumors is found in the tumor parenchyma or in the stroma immediately surrounding the parenchyma. Confirmation of amyloid in this MAC lesion included positive staining with Dylon and electron microscopic identification of 6- to 10-nm straight filaments. A degenerative transformation of tonofilaments or cytoplasmic microfilaments into amyloid filaments has been demonstrated by ultrastructural study (19-21). Kobayashi and Hashimoto (21) demonstrated that tumor-associated amyloid was derived from degenerated epidermal keratinocytes through filamentous degeneration. It is though that through the same mechanisms as cited above, epithelial cells comprising cell nests or cystic structures have undergone some cytological degeneration, resulting in amyloid deposition.
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Fig. 14. Amyloid deposit (A) is seen around the keratinous cysts. Inset: On higher magnification, amyloid is composed of straight, non-branching, non-anastomosing 6-10 nm filaments (uranyl acetate & lead citrate).
References 1. Coldstein Dj, Barr RJ, Santa Cruz DJ. Microcystic adnexal carcinoma: a distinct clinicopathologic entity. Cancer 1982: 50: 566. 2. Cooper PH, Millis SE. Microcystic adnexal carcinoma. J Am Acad Dermatol 1984: 10: 908. 3. Cooper PH. Sclerosing carcinoma of sweat ducts (microcystic adnexal carcinoma). Arch Dermatol 1986: 122: 101. 4. Eleischmann HE, Roth Rj, Wood CC, Nickoloff BJ. Microcystic adnexal carcinoma treated by microscopically controlled excision. J Dermatol Surg Oncol 1984: 10: 873. 5. Lupton GP, McMarlin SL. Microcystic adnexal carcinoma: report of a case with 30-year follow-up. Arch Dermatol 1986: 122: 286. 6. Nickoloff BJ, Fleischmann HE, Carmel J, Wood CC, Roth RJ. Microcystic adnexal carcinoma: immunohistologic observations suggesting dual (pilar and eccrine) differentiation. Arch Dermatol 1986: 122: 290. 7. Rongioletti F, Grosshans E, Rebora A. Microcystic adnexal carcinoma. BrJ Dermatol 1986: 115: 101. 8. Takemiya M, Shiraishi S, Saeki N, Ohtsuka H, Miki Y. Microcystic adnexal careinoma with Langerhans cells. J Dermatol (Tokyo) 1988: 15: 428. 9. Glatt HJ, Proia AD, Tsoy EA, Fetter BF, Klintworth GK, Neuhaus SR, Font RL. Malignant syringoma of the eyelid. Ophthalmology 1984: 91: 987.
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10. Lipper S, Peiper SC. Sweat gland carcinoma with syringomatous features: a light microscopic and ultrastructural study. Cancer 1979: 44: 157. 1 I. Cooper PH, Mills SE, Leonard DD, et al. Sclerosing sweat duct (syringomatous) carcinoma. Am J Surg Pathol 1985: 9: 422. 12. Yanagihara M, Mehregan AH, Mehregan DR. Staining of amyloid with cotton dyes. Arch Dermatol 1984: 120: 1184. 13. Penneys NS, Nadji M, McKinney EC. Carcinoembrionic antigen present in human eccrine sweat. J Am Acad Dermatol 1981: 4: 401. 14. Penneys NS, Nadji M, Morales A. Carcinoembrionic antigen in benign sweat gland tumors. Arch Dermatol 1982: 118: 225. 15. Kahn HJ, Baumal R, Marks A. The value of immunohistoehemical studies using antibody to S-100 protein in dermatopathoiogy. Int J Dermatol 1984: 23: 38. 16. Penneys NS. Immunohistochemistry of adnexal neoplasms. J Cutan Pathol 1984: II: 357. 17. Kanitakis J, Zambruno G, Viac J, Panzini H, Thivolet J. Expression of neural-tissue markers (S-100 protein and Leu-7 antigen) by sweat gland tumors of the skin: an immunohistoehemical study. J Am Acad Dermatol 1987: 17: 187. 18. Apisarnthanarax P, Bovenmyer DA, Mehregan AH. Combined adnexal tumor of the skin. Arch Dermatol 1984: 120: 231.
Microcystic adnexal carcinoma 19. Hashimato K, King LE Jr. Secondary localized cutaneous amyloidosis associated with actinic keratosis. J Invest Dermatol 1973: 61: 293. 20. Hashimoto K, Brownstein MH. Localized amyloidosis in basal cell epitheliomas. Acta Derm Venereol (Stockh) 1973: 53: 331.
21. Kobayashi H, Hashimoto K. Amyloidogenesis in organlimited cutaneous amyloidosis: an antigenic identity between epidermal keratin and skin amyloid. J Invest Dermatol 1983: 80: 66.
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Haruhisa Kato, Nobuyuki Mizuno, Koichi Nakagawa, Masayoski Furukawa, Toshio Hamada
Kato H, Mizuno N, Nakagawa K, Furukawa M, Hamada T. Microcystic adnexal carcinoma: a light microscopic, immunohistoehemical and ultrastructural study. J Cutan Pathol 1990: 17: 87-95.
Haruhisa Kato, Department of Dermatology, Osaka City University Medical School, 1-5-7, Asahimachi, Abeno-ku, Osaka 545, Japan
There have been many reports and studies of microcystic adnexal carcinoma (MAC) since Goldstein et al. (1) first described 6 cases in 1982. Clinically, the neoplasm is locally aggressive, and tends to recur despite local excision. Histopathologically, it seldom shows cellular atypia and mitosis, and exhibits both follicular and sweat gland differentation (2, 3). One of the most characteristic microscopic features is multiple nests and strands of squamous or basaloid cells, forming keratin-filled cysts (1-8). Some pathologists prefer the term malignant syringoma (9), or sweat gland carcinoma with syringomatous features (10) to MAC; and the term sclerosing sweat duct (syringomatous) carcinoma was used by Cooper et al. (2, 11). Ultrastructural featues of MAC have not been thoroughly investigated. Only a few of the reported
Department of Dermatology, Osaka City University Medical School, Japan
Accepted September 18, 1989
studies have included any ultrastructural description (8, 10). We report MAC in which amyloid deposition was observed, and discuss the light and electron microscopic features of the disease.
Case report
In 1987, an 82-year-old woman was admitted to the Osaka City University Hospital for evaluation of a lesion present for 10 years on the right nasolabial area. The lesion had gradually increased in size and, become ulcerated and friable. The patient denied having pain, paresthesia, or anesthesia in the area of involvement. There was no history of previous radiotherapy to the face. At the time of admission, there was an ulcerated, indurated lesion with a 87
H. Kato et al.
gen (CEA) (DAKO PAP kit), and S-100 protein (DAKO PAP kit). For electron microscopic examinations, specimens were cut into about 1 X 1 X 4 mm cubes and fixed at 4°C, in 2.5% gluteraldehyde buffered with 0.1 M phosphate buffer (pH 7.4) for 1 h and post-fixed with 1% osmium tetroxide in 0.1 M phosphate buffer (pH 7.4) for 2 h. Routine methods were used for embedding, thin sectioning and staining. The sections were examined with a Hitachi H-300 electron microscope. Results Light microscopy
Fig. I. Light photomicrograph of microcystic adnexal carcinoma. Upper and middermis infiltrated by keiatinous cysts and onionlike globes, surrounding non-neoplastic pilosebaceous follicles (H&E, X30).
smooth, shiny surface and small telangiectases. The lesion involved the right nasolabial area, nasal ala and the upper right lip, and measured 2.0 X 2.8 cm. There was no cervical lymphadenopathy, other skin tumor or neurological deficit. The clinical impression was morphea-like basal cell epithelioma, and the patient underwent a wide resection, with a margin of 0.5 cm from the border of the tumor. The right nasal ala was removed. The lesion grossly extended into the underlying mucosa. Material and methods
The surgical specimens were processed for light microscopic, immunohistoehemical and electron microscopic studies. For light microscopic examinations, formalin-fixed, paraffin-embedded specimens were cut at 7 |im, and stained with H&E and Dylon (12). For immunoperoxidase study, the parafTin-embedded specimens were sectioned 7-|xmthick, and examined using the peroxidase-antiperoxidase (PAP) technique for carcinoembrionic anti88
Histological examination showed the tumor contained 2 components (Fig. 1). The first component comprised small solid nests and strands of tumor cells irregularly distributed throughout the dermis. In addition, a large number of ductal structures of varying size and shape were seen (Fig. 2). The cells comprising these cell nests, strands and lining of ductal structures were cuboid to round with a moderate to abundant amount of eosinophilic cytoplasm. Their nuclei were small and hyperchromatic. Some contained amorphous eosinophilic material within the lumen. Cytologic atypicality was mild or lacking, and mitotic figures were absent. The second component was composed of small keratinous cysts lined by squamous epithelium (Fig. 3). The keratinous cysts were largest and most numerous in the superficial dermis. They were rounded or oval, lined by a two-cell layer. They sometimes had one or more buds or elongated tadpole-like appendages. They contained dense, laminated keratin with focal calcification. There were groups of polygonal or cuboid cells with small, hyperchromatic nuclei and abundant clear cytoplasm, adjacent to the keratinized cysts (Fig. 4). In the upper dermis, connections between the tumor cells and the epidermis or adnexa were seen in some areas. In the middle and lower dermis, cystic structures were smaller, and small ductal structures were more numerous in the lower dermis. These were often much smaller and were associated with a dense hyalinized, collagenous stroma. Invasion to the subcutaneous tissue and perineural spaces was noted in some areas. Distinct amyloid deposits were demonstrated by Dylon staining (12) (Fig. 10). The amyloid material stained a bright orange color with Dylon, and was located within the collagenous stroma around the keratinous cysts. Immunohistochemistry
Immunohistoehemical staining using the peroxidase-antiperoxidase (PAP) technique for carcinoembrionic antigen (CEA) was focally positive on
Microcystic miuruuysiib adnexal auiicxiii carcinoma caruinuma
Fj^. 2. In the lower dermis, well-developed, tubulo-alveolar ductal structures, embedded in dense, fibrous tissue. Some contained amorphous eosinophilic materials within the lumen (H&E, X 125). - Fig. 3. Keratinous cysts lined by squamous epithelium separated by concentric bands of moderately cellular fibrous tissue. Some of them contained calcified keratin material (H&E, X60). - Fig. 4. Groups of polygonal or cuboid cells with small, hyperchromatic nuclei and abundant pale-staining cytoplasms (H&E, X\25).-Fig. 5. Amyloid deposits (arrowheads) are seen within the collagenous stroma (Dylon, X300). - Fig. 6. Immunoperoxidase staining for carcinoembrionic antigen: it is focally positive on the dilated ducts (diaminobenzidine & hematoxylin, X 125). -Ff^. 7. Immunoperoxidase staining with anti-S-100 protein antibody. Larger solid cell nests, showing positive staining in the dendritic cells (diaminobenzidine & hematoxylin, X125).
H. Kato et al. Fig. 8. Electron microscopic findings of MAC. Concentric layers of squamous epithelial cells forming a solid cell nest (uranyl acetate & lead citrate).
the ductal lining surface of tumor cells and in the amorphous contents within the lumen. CEA was seen focally in the contents of some keratinous cysts, however, no squamous epithelial cells were positively stained (Fig. 6). S-100 protein was negative in the ductal structures except for the cells located peripheral to the lining cells and the dendritic cells within the larger solid cell nests in the superficial dermis (Fig. 7).
Electron microscopy Electron microscopic examination showed concentric layers of epithelial cells with desmosomes and short cytoplasmic processes (Fig. 8). Most cells were spindle-shaped and interdigitated with each other by desmosomes, showing keratinization from peripheral layer toward the center of the nests. The epithelial cells had a number of filaments in their cytoplasm. Abrupt transition from nucleate to anucleate cells was accompanied by the loss of all cytoplasmic organelles. The keratinized cells were filled with abundant tonofilaments and retained their desmosomal connections (Fig. 9). Some contained electron-dense keratinous material at the center of the nests (Fig. 10). Numerous glycogen particles
90
were distributed within the cytoplasm of both nonkeratinized and keratinized epithelial cells. The other type of cell nests and ductal structures showed glandular or ductal differentiation. The cells comprising the nests had a large, rounded or oval nucleus with one or no nucleolus. Within the cytoplasm of the cells there were numerous mitochondria and extensive rough-surfaced endoplasmic reticulum (Fig. 11). The most characteristic feature of the cells comprising small solid nests and ductal structures was the extensive plication of the plasma membrane to form long villous folds (Fig. 12). These interdigitated with similar folds of adjacent cells by desmosomes. Intercellular spaces were fairly extensive. Some of such cells had localized aggregations of microfilaments within the cytoplasm (Fig. 13). In other areas, cell-to-cell contact was made by closely interlocked villous folds of plasma membrane. Short, stumpy microvilli were seen along the luminal plasma membrane. The plasma membranes of apposed cells were studded with short desmosomes and tight junctions. Myoepithelial cells were located at the periphery of the cell nests, being separated from the surrounding stroma by basal lamina. These ultrastructural findings were indicative of glandular differentiation of the tumor.
Microcystic adnexal carcinoma
Ing 9 Ihc kcKitmous cells contained aggtegates of cytoplasmic filaments and numerous glycogen particles Cell-to-cell contact is made by desmosomes (uranyl acetate & lead citrate).
Close association of amyloid deposits with tumor cell nests was another peculiar finding of interest. Amyloid deposits were seen around the solid cell nests of follicular differentiation, and surrounded by the long cytoplasmic processes of fibroblasts. They were composed of straight, non-branching filaments 6-10 nm in diameter (Fig. 14).
Discussion Goldstein et al. (1) reported 6 patients with MAC in 1982, describing it as an unusual, highly locally aggressive adnexal neoplasm with a propensity for involving the upper lips of middle-aged women. Our patient was an elderly woman with a lesion involving the right nasal ala, nasolabial region and the upper lip, clinically resembling morphea-like basal cell epithelioma. Biopsies showed a variety of light microscopic patterns that in different areas suggested trichoepithelioma with horn cysts and syringoma. However, MAC differs from both syringoma and desmoplastic trichoepithelioma in its locally aggressive nature. Its histological appearances include keratinous cysts, abortive follicle-like struc-
tures embedded in a desmoplastic stroma, ducts and gland-like structures. Despite the infrequency of mitotic activity and cytologic atypia, MAC typically extends deep into skeletal muscle and invades perineural spaces. In this, it resembles eccrine gland carcinoma, but is distinguished by its benign cytologic appearance. Because of invasive growth, frequent recurrence, and both pilar and eccrine differentiation, the term microcystic adnexal carcinoma is preferred and signifies to the clinician an aggressive, infiltrating lesion (6). In our study, several fields were characterized by abundant horn cyst formation surrounded by keratinocytes, and some of them showed early calcification. These findings seemed to indicate pilar differentiation of the tumor. In other fields, ductal structures were seen lined by two layers of cuboid cells. The CEA immunohistoehemical results are identical to those previously reported by Nickoloff et al. (6) and Takemiya et al. (8). Nickoloff et al. (6) demonstrated CEA was present in the lumina of small ducts or on the ductal lining surface of the tumor cells and absent in the keratinous cysts. The
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Microcystic adnexal carcinoma Fig. JO. Some keratinous cysts undergo keratinization from peripheral layer toward the center of the nests, and contain electron-dense keratinous material (uranyl acetate & lead citrate). - Fig. IL A solid cell nest of eccrine differentiation. The cells comprising the nest have a large, rounded to oval nucleus and numerous mitochondria. Cell-to-cell contact is made by folded plasma membrane of opposing cells and focal desmosomes. BL: basal lamina, M: myoepithelial cell (uranyl acetate & lead citrate). - Fig. 12. Extensive plications of plasma membranes are seen in the cells showing ductal differentiation (uranyl acetate & lead citrate). - Fig. 13. On the luminal surface, there are numerous stumpy microvilli. Cell-to-cell contact is made by extensive plications of the plasma membranes and focal desmosomes. Aggregations of cytofilaments are seen (uranyl acetate & lead citrate).
positive immunoperoxidase staining for CEA in tumor tissue showing ductal formation is good evidence of sweat gland differentiation. CEA has been shown to be expressed in the skin by sweat glands and tumors arising therefrom (13, 14). Although the demonstration of CEA in a sweat gland neoplasm does not differentiate apocrine from eccrine-derived tumors, it may be helpful in separating tumors that arise from sweat gland epithelium from other adnexal tumors of pilar and sebaceous derivation (14). This notion is confirmed by the ultrastructural observation of eccrine sweat gland-like structures in the tumor tissue where secretory cells interlocked by folded plasma membranes and desmosomes, with basally located myoepithelial cells. The lack of CEA staining of the areas with the follicular appearance also supports the concept that this neoplasm combines differentiation toward both sweat gland and pilar structures. S-100 protein is an acidic, calciumbinding protein, and has been detected in normal skin and various skin tumors. In normal skin, S-100 protein is detected in the dendritic cells of epidermis (melanocytes and Langerhans cells), Schwann cells, and cells of the sweat gland apparatus (15). S-100 protein has been recently found in eccrine, but not in apocrine, sweat glands. Although initially believed to be present in myoepithelial cells (15), it seems that also eccrine clear secretory cells express this protein (16, 17). In the present case, S-100 protein was detected in the dendritic cells within the solid cell nests in the superficial dermis. Although they could not be demonstrated by electron microscopy, melanocytes or Langerhans cells are the most likely candidates for the dendritic cells situated in the solid cell nests. In fact, Takemiya et al. (8) demonstrated Langerhans cells within the epithelial cell nests of MAC by immunoperoxidase and ultrastructural examinations. Electron microscopic study also revealed that the tumor had two components, showing both pilar and eccrine differentiation. There have been few studies that included ultrastructural observations (8, 10). Electron microscopic examination was performed by Lipper and Peiper (10), and these findings resembled those described for normal eccrine ducts with ductal structures, luminal cells, microvilli and desmosomes, as seen in the present study. However, they did not refer to the ultrastructure of keratinous
cysts and solid cell nests. In syringoma and acrospiroma, the eccrine ducts may at times show significant keratinization with horn cyst formation and "follicular differentiation". It is still possible that keratinous cysts may show a peculiar form of keratinization, since trichohyaline granules were absent in the epithelial cells of the keratinous cysts. Immunostaining may play an important role in identifying the origin of the neoplastic cells. CEA is likely to be absent in purely squamous foci. The negative immunohistoehemical staining of CEA in the kerationous cysts is not suggestive of eccrine differentiation, but shows pilar differentiation. It is still unknown why MAC represents more than one direction of differentiation. Apisarnthanarax et al. (18) proposed the idea that pluripotential cells of the epidermis and cutaneous adnexa were capable of differentiating in more than one direction in a neoplalsm, since all of the cutaneous appendages arose from the embryonal epidermis. They proposed the term 'combined adnexal tumor of the skin' to denote such a neoplasm. Amyloid substance is sometimes encountered in many benign and malignant skin tumors of epithelial origin: basal cell epithelioma, actinic keratosis, Bowen's disease, seborrheic keratosis, calcifying epithelioma, cylindroma and Spitz nevus have all been known to contain amyloid (19, 20). Amyloid in these tumors is found in the tumor parenchyma or in the stroma immediately surrounding the parenchyma. Confirmation of amyloid in this MAC lesion included positive staining with Dylon and electron microscopic identification of 6- to 10-nm straight filaments. A degenerative transformation of tonofilaments or cytoplasmic microfilaments into amyloid filaments has been demonstrated by ultrastructural study (19-21). Kobayashi and Hashimoto (21) demonstrated that tumor-associated amyloid was derived from degenerated epidermal keratinocytes through filamentous degeneration. It is though that through the same mechanisms as cited above, epithelial cells comprising cell nests or cystic structures have undergone some cytological degeneration, resulting in amyloid deposition.
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Fig. 14. Amyloid deposit (A) is seen around the keratinous cysts. Inset: On higher magnification, amyloid is composed of straight, non-branching, non-anastomosing 6-10 nm filaments (uranyl acetate & lead citrate).
References 1. Coldstein Dj, Barr RJ, Santa Cruz DJ. Microcystic adnexal carcinoma: a distinct clinicopathologic entity. Cancer 1982: 50: 566. 2. Cooper PH, Millis SE. Microcystic adnexal carcinoma. J Am Acad Dermatol 1984: 10: 908. 3. Cooper PH. Sclerosing carcinoma of sweat ducts (microcystic adnexal carcinoma). Arch Dermatol 1986: 122: 101. 4. Eleischmann HE, Roth Rj, Wood CC, Nickoloff BJ. Microcystic adnexal carcinoma treated by microscopically controlled excision. J Dermatol Surg Oncol 1984: 10: 873. 5. Lupton GP, McMarlin SL. Microcystic adnexal carcinoma: report of a case with 30-year follow-up. Arch Dermatol 1986: 122: 286. 6. Nickoloff BJ, Fleischmann HE, Carmel J, Wood CC, Roth RJ. Microcystic adnexal carcinoma: immunohistologic observations suggesting dual (pilar and eccrine) differentiation. Arch Dermatol 1986: 122: 290. 7. Rongioletti F, Grosshans E, Rebora A. Microcystic adnexal carcinoma. BrJ Dermatol 1986: 115: 101. 8. Takemiya M, Shiraishi S, Saeki N, Ohtsuka H, Miki Y. Microcystic adnexal careinoma with Langerhans cells. J Dermatol (Tokyo) 1988: 15: 428. 9. Glatt HJ, Proia AD, Tsoy EA, Fetter BF, Klintworth GK, Neuhaus SR, Font RL. Malignant syringoma of the eyelid. Ophthalmology 1984: 91: 987.
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10. Lipper S, Peiper SC. Sweat gland carcinoma with syringomatous features: a light microscopic and ultrastructural study. Cancer 1979: 44: 157. 1 I. Cooper PH, Mills SE, Leonard DD, et al. Sclerosing sweat duct (syringomatous) carcinoma. Am J Surg Pathol 1985: 9: 422. 12. Yanagihara M, Mehregan AH, Mehregan DR. Staining of amyloid with cotton dyes. Arch Dermatol 1984: 120: 1184. 13. Penneys NS, Nadji M, McKinney EC. Carcinoembrionic antigen present in human eccrine sweat. J Am Acad Dermatol 1981: 4: 401. 14. Penneys NS, Nadji M, Morales A. Carcinoembrionic antigen in benign sweat gland tumors. Arch Dermatol 1982: 118: 225. 15. Kahn HJ, Baumal R, Marks A. The value of immunohistoehemical studies using antibody to S-100 protein in dermatopathoiogy. Int J Dermatol 1984: 23: 38. 16. Penneys NS. Immunohistochemistry of adnexal neoplasms. J Cutan Pathol 1984: II: 357. 17. Kanitakis J, Zambruno G, Viac J, Panzini H, Thivolet J. Expression of neural-tissue markers (S-100 protein and Leu-7 antigen) by sweat gland tumors of the skin: an immunohistoehemical study. J Am Acad Dermatol 1987: 17: 187. 18. Apisarnthanarax P, Bovenmyer DA, Mehregan AH. Combined adnexal tumor of the skin. Arch Dermatol 1984: 120: 231.
Microcystic adnexal carcinoma 19. Hashimato K, King LE Jr. Secondary localized cutaneous amyloidosis associated with actinic keratosis. J Invest Dermatol 1973: 61: 293. 20. Hashimoto K, Brownstein MH. Localized amyloidosis in basal cell epitheliomas. Acta Derm Venereol (Stockh) 1973: 53: 331.
21. Kobayashi H, Hashimoto K. Amyloidogenesis in organlimited cutaneous amyloidosis: an antigenic identity between epidermal keratin and skin amyloid. J Invest Dermatol 1983: 80: 66.
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