The Journal of Dermatology Vol. 5: 279-282. 1978
PROLIFERATING TRICHILEMMAL CYST ON THE BACK KUNIHIKO YOSHIKAWA
AND
AYAKO NAKANISHI
ABSTRACT
A large intradermal tumor, 5x4cm in size, developed on the back of 67-year-old Japanese woman. Histological examination revealed a large cyst next to a mass of irregular proliferation of the cystic wall, most of which showed typical triehilemmal keratinization. The accompanying partial calcification of the homogeneous cystic content allowed the diagnosis of proliferating triehilemmal cyst. Since this tumor is quite rare among the Japanese, the 15 cases so far reported in the Japanese literature are reviewed and summerized.
The trichilemmal cyst, which was formerly called sebaceous cyst, was renamed by Pinkus (1) based on the histological finding that the cyst wall shows trichilemmal keratinization similar to telogen hair bulb. It is much less common than its counterpart, the epidermal cyst. Although these two cysts cannot be differentiated from each other by their clinical appearance, the former is characteristicly located on the scalp area of the aged women. Sometimes, the cyst IS accompanied by proliferative changes in the cystic wall and then called a proliferating triehilemmal cyst. Since this tumor is quite rare, and Japanese cases so far reported were mostly found on and near the scalp, this case found on the trunk seems to be worth reporting.
first examined. The tumor was located on the left scapular area, showed well-demarcated protrusion, and its surface was irregularly convexed with brown to dark brown coloration (Fig. 1). On palpation, the tumor was mostly solid and the remaining small part showed a soft cystic consistency. It was fixed to the overlying skin but mobile against the underlying tissue. The patient's family history and past history was unremarkable. The entire tumor was resected and examined
REPORT OF A CASE
A 67 -year-old Japanese woman has had a symptomless nodule on her back for the last fourteen years. The nodule gradually enlarged to make a large intradermal tumor of 4 x5 cm when she was Received December 1, 1977; accepted for publication July 14, 1978. From the Department of Dermatology, Nagoya City University School of medicine, Mizuho-cho, Mizuho-ku, Nagoya, Japan. This case was presented at the 70th Meeting of Dermatologists in Kinki District held in Osaka, Japan.
Fig, 1.
A large tumor on the left scapular area.
280
YOSHIKA WA FT AL
histologically. It was sharply demarcated from the surrounding tissues. Figure 2 shows a scanning view of a histological section on which the cystic element and the proliferating element were observed close together. Small cystic elements were also seen among the irregular proliferating elements. The cysts contained amorphous eosinophilic material, and the architecture of the cystic wall was typical of a trichilemmal cyst. The outermost cells were small, often showed palisading arrangement and become larger as they move inward. They had an abundant eosinophilic cytoplasm and an unclear cellular border, and then merged into amorphous cystic content without the formation of a definite granular layer. However, some cells have keratohyaline
granules and even a partially formed incomplete granular layer as shown in Fig. 3. Some squamous eddy-like structures, individual cell keratinization and vacuolated cells were seen (Fig. 4). Calcification and a small number of cholesterol crystals were among the contents of some of the cysts. The structure of the proliferating element was essentially the same as that of the cystic wall described above. Figure 5 shows a part of it which tended to form small cystic cavities. The connective tissue surrounding the proliferating elements showed a slight granulomatous reaction accompanied with a few foreign body giant cells. The overlying epidermis was slightly atrophic and accompanied with an increase of melanin in the basal layer .
Fig. 2. Scanning view of the histological section showing a large cystic element and a proliferating element side by side. Small cystic cavities were also seen within the latter. H-Estain.
Fig. 4. Squamous eddy-like structures in the cystic wall. Individual cell keratinization is also seen. H-E stain.
Fig. 3. Architecture of the cystic wall. Note the palisading arrangement of the outermost cells, An incomplete granular layer is seen. H-E stain.
Fig. 5. Structure of the proliferating element. Small cysticcavities are formed. H-E stain.
281
PROLIFERATING TRICHILEMMAL CYS'I
Table L No I 2 3 4 5 6 7 8 9 10 11
12 13 14 15 16
Age 67 68 48 49 53 67 76 72 36 31 70 67 71 62 60 67
Sex
Size (cm)
M F F F F F F M F F F F F F F F
4 X2 about 3 L4XL3 about 2 8 x7 about L8 3x3 3x3 about 0.5 3x3 about 1.5 about 1.8 2.1 X2.2 about 3 about 2 4X5
Reported cases in Japanese Site
Duration
Reference
frontal temporal frontal parietal parietal frontal parietal upper arm parietal occipital frontal frontal scapular parietal parietal scapular
3,5M lOY L5M IY 15-16 Y lOY IY 20Y 3Y IY 5Y lOY several Y about 40Y 2Y 14Y
Nitto & Goto ') Kasahara et aL4) Homma " Kotajima er aL5) Kotajima et aL5) Yamaguchi et al ." Kimura & Tanakav Nakayama et al. * Nakakita & Masuda" Imai et a1. 7) Osamura & Yasudav Matsusaki et al. 9) Matsusaki et aJ.9) Hino et aL 10) Hino et al. 10) This case
": presented but not published as a report. There have been, at least two more presented cases which are not listed here because they have not been published.
DISCUSSION
The histological findings described here are characteristic of proliferating trichilemmal cyst. The occasional keratohyaline granules and incomplete granular layer, however, might allow us to call this tumor a proliferating mixed cyst. Although trichilemmal cyst IS seen predominantly on and around the scalp, it is sometimes seen elsewhere. According to recent observation by Leppard and Sanderson (2) of 149 cysts from 65 patients in England, almost 90% of them were found on the scalp and only 2% showed proliferative changes. This suggests that the occurrence of this tumor on the area other than the scalp is rather rare. Reported cases among Japanese have also been predominantly female, and have developed the tumor on or near the scalp with two exceptions, one being an unpublished case by Nakayama et al., which was seen on the arm as a verrucous tumor from its early stages and showed partial malignant changes suggesting Bowen's disease, and the other reported by Matsusaki et al. (9)
(Table 1). Kimura (6), by histological observation, tentatively divided this tumor into two parts, i.e ., those proliferated from pre -existing cyst wall and those in which cyst formation is secondary to cellular proliferation. The former area is characterized by the presence of a large cystic cavity in the center. This case, showing large cystic and solid proliferating elements side by side, cannot readily be put into either of these two groups, but would be assumed to belong to the former in which some unknown mechanism caused proliferation of the cells in the pre-existing cystic wall. REFERENCES I) Pinkus, H.: "Sebaceous cysts" are trichilemrnal cysts, Arch. Dermatol., 99: 544-555, 1969. 2) Leppard, B.]. and Sanderson, K.V.: The natural history of trichilemmal cysts, Brit. j. Dermatol., 94: 379-390, 1976. 3) Nitta, H. and Goto, H.: Proliferating pilar cysts with partial malignant change, Rinsho Derma. (Tokyo), 22: 171-177, 1968 (in Japanese). 4) Kasahara, N., Shiratori , A. and Shimazaki, T.: Pro-
282
YOSHIKAWA 1':1 M.
liferating epidermoid cyst, Rinsho Derma. (Tokyo), II: 164-170. 1969 (in Japanese). 5) Kotajima , S., Nitta. H.. Miyazato, H., Niki, T. and Ikeda. S.: Two Cases of proliferating trichilemmal cyst, Rinsho Derma. (Tokyo), 15: 191-197, 1973 (in Japanese). 6) Kimura. S. and Tanaka, R.: Proliferating trichilemmal cyst. Jap. j. Clin. Dermat., 28: 543-548, 1974 (in Japanese). 7) Imai , S., Hamamatsu, T., Ikeda, S. and Ishihara, K.: Proliferating trichilemmal cyst. Rinsho Derma.
(Tokyo), 19: 125-131, 1977 (in Japanese). 8) Osamura, H. and Yasuda, T.: Proliferating trichilemmalcyst, Rmsho Derma. (Tokyo), 19: 121-124, 1977 (in Japanese). 9) Marsusaki , T., Yamaguchi, Z. and Morioka, S.: Two cases of proliferating trichilemmal cyst, Jap. j. Dermat ., 88: 37-42,1978 (in Japanese). 10) Hino, Y.. Nishimura, M. and Koda, H.: Proliferating trichilemmal cyst. Nishmihon ]. Derm., 40: 259-267, 1978 (in Japanese).
PROLIFERATING TRICHILEMMAL CYST ON THE BACK KUNIHIKO YOSHIKAWA
AND
AYAKO NAKANISHI
ABSTRACT
A large intradermal tumor, 5x4cm in size, developed on the back of 67-year-old Japanese woman. Histological examination revealed a large cyst next to a mass of irregular proliferation of the cystic wall, most of which showed typical triehilemmal keratinization. The accompanying partial calcification of the homogeneous cystic content allowed the diagnosis of proliferating triehilemmal cyst. Since this tumor is quite rare among the Japanese, the 15 cases so far reported in the Japanese literature are reviewed and summerized.
The trichilemmal cyst, which was formerly called sebaceous cyst, was renamed by Pinkus (1) based on the histological finding that the cyst wall shows trichilemmal keratinization similar to telogen hair bulb. It is much less common than its counterpart, the epidermal cyst. Although these two cysts cannot be differentiated from each other by their clinical appearance, the former is characteristicly located on the scalp area of the aged women. Sometimes, the cyst IS accompanied by proliferative changes in the cystic wall and then called a proliferating triehilemmal cyst. Since this tumor is quite rare, and Japanese cases so far reported were mostly found on and near the scalp, this case found on the trunk seems to be worth reporting.
first examined. The tumor was located on the left scapular area, showed well-demarcated protrusion, and its surface was irregularly convexed with brown to dark brown coloration (Fig. 1). On palpation, the tumor was mostly solid and the remaining small part showed a soft cystic consistency. It was fixed to the overlying skin but mobile against the underlying tissue. The patient's family history and past history was unremarkable. The entire tumor was resected and examined
REPORT OF A CASE
A 67 -year-old Japanese woman has had a symptomless nodule on her back for the last fourteen years. The nodule gradually enlarged to make a large intradermal tumor of 4 x5 cm when she was Received December 1, 1977; accepted for publication July 14, 1978. From the Department of Dermatology, Nagoya City University School of medicine, Mizuho-cho, Mizuho-ku, Nagoya, Japan. This case was presented at the 70th Meeting of Dermatologists in Kinki District held in Osaka, Japan.
Fig, 1.
A large tumor on the left scapular area.
280
YOSHIKA WA FT AL
histologically. It was sharply demarcated from the surrounding tissues. Figure 2 shows a scanning view of a histological section on which the cystic element and the proliferating element were observed close together. Small cystic elements were also seen among the irregular proliferating elements. The cysts contained amorphous eosinophilic material, and the architecture of the cystic wall was typical of a trichilemmal cyst. The outermost cells were small, often showed palisading arrangement and become larger as they move inward. They had an abundant eosinophilic cytoplasm and an unclear cellular border, and then merged into amorphous cystic content without the formation of a definite granular layer. However, some cells have keratohyaline
granules and even a partially formed incomplete granular layer as shown in Fig. 3. Some squamous eddy-like structures, individual cell keratinization and vacuolated cells were seen (Fig. 4). Calcification and a small number of cholesterol crystals were among the contents of some of the cysts. The structure of the proliferating element was essentially the same as that of the cystic wall described above. Figure 5 shows a part of it which tended to form small cystic cavities. The connective tissue surrounding the proliferating elements showed a slight granulomatous reaction accompanied with a few foreign body giant cells. The overlying epidermis was slightly atrophic and accompanied with an increase of melanin in the basal layer .
Fig. 2. Scanning view of the histological section showing a large cystic element and a proliferating element side by side. Small cystic cavities were also seen within the latter. H-Estain.
Fig. 4. Squamous eddy-like structures in the cystic wall. Individual cell keratinization is also seen. H-E stain.
Fig. 3. Architecture of the cystic wall. Note the palisading arrangement of the outermost cells, An incomplete granular layer is seen. H-E stain.
Fig. 5. Structure of the proliferating element. Small cysticcavities are formed. H-E stain.
281
PROLIFERATING TRICHILEMMAL CYS'I
Table L No I 2 3 4 5 6 7 8 9 10 11
12 13 14 15 16
Age 67 68 48 49 53 67 76 72 36 31 70 67 71 62 60 67
Sex
Size (cm)
M F F F F F F M F F F F F F F F
4 X2 about 3 L4XL3 about 2 8 x7 about L8 3x3 3x3 about 0.5 3x3 about 1.5 about 1.8 2.1 X2.2 about 3 about 2 4X5
Reported cases in Japanese Site
Duration
Reference
frontal temporal frontal parietal parietal frontal parietal upper arm parietal occipital frontal frontal scapular parietal parietal scapular
3,5M lOY L5M IY 15-16 Y lOY IY 20Y 3Y IY 5Y lOY several Y about 40Y 2Y 14Y
Nitto & Goto ') Kasahara et aL4) Homma " Kotajima er aL5) Kotajima et aL5) Yamaguchi et al ." Kimura & Tanakav Nakayama et al. * Nakakita & Masuda" Imai et a1. 7) Osamura & Yasudav Matsusaki et al. 9) Matsusaki et aJ.9) Hino et aL 10) Hino et al. 10) This case
": presented but not published as a report. There have been, at least two more presented cases which are not listed here because they have not been published.
DISCUSSION
The histological findings described here are characteristic of proliferating trichilemmal cyst. The occasional keratohyaline granules and incomplete granular layer, however, might allow us to call this tumor a proliferating mixed cyst. Although trichilemmal cyst IS seen predominantly on and around the scalp, it is sometimes seen elsewhere. According to recent observation by Leppard and Sanderson (2) of 149 cysts from 65 patients in England, almost 90% of them were found on the scalp and only 2% showed proliferative changes. This suggests that the occurrence of this tumor on the area other than the scalp is rather rare. Reported cases among Japanese have also been predominantly female, and have developed the tumor on or near the scalp with two exceptions, one being an unpublished case by Nakayama et al., which was seen on the arm as a verrucous tumor from its early stages and showed partial malignant changes suggesting Bowen's disease, and the other reported by Matsusaki et al. (9)
(Table 1). Kimura (6), by histological observation, tentatively divided this tumor into two parts, i.e ., those proliferated from pre -existing cyst wall and those in which cyst formation is secondary to cellular proliferation. The former area is characterized by the presence of a large cystic cavity in the center. This case, showing large cystic and solid proliferating elements side by side, cannot readily be put into either of these two groups, but would be assumed to belong to the former in which some unknown mechanism caused proliferation of the cells in the pre-existing cystic wall. REFERENCES I) Pinkus, H.: "Sebaceous cysts" are trichilemrnal cysts, Arch. Dermatol., 99: 544-555, 1969. 2) Leppard, B.]. and Sanderson, K.V.: The natural history of trichilemmal cysts, Brit. j. Dermatol., 94: 379-390, 1976. 3) Nitta, H. and Goto, H.: Proliferating pilar cysts with partial malignant change, Rinsho Derma. (Tokyo), 22: 171-177, 1968 (in Japanese). 4) Kasahara, N., Shiratori , A. and Shimazaki, T.: Pro-
282
YOSHIKAWA 1':1 M.
liferating epidermoid cyst, Rinsho Derma. (Tokyo), II: 164-170. 1969 (in Japanese). 5) Kotajima , S., Nitta. H.. Miyazato, H., Niki, T. and Ikeda. S.: Two Cases of proliferating trichilemmal cyst, Rinsho Derma. (Tokyo), 15: 191-197, 1973 (in Japanese). 6) Kimura. S. and Tanaka, R.: Proliferating trichilemmal cyst. Jap. j. Clin. Dermat., 28: 543-548, 1974 (in Japanese). 7) Imai , S., Hamamatsu, T., Ikeda, S. and Ishihara, K.: Proliferating trichilemmal cyst. Rinsho Derma.
(Tokyo), 19: 125-131, 1977 (in Japanese). 8) Osamura, H. and Yasuda, T.: Proliferating trichilemmalcyst, Rmsho Derma. (Tokyo), 19: 121-124, 1977 (in Japanese). 9) Marsusaki , T., Yamaguchi, Z. and Morioka, S.: Two cases of proliferating trichilemmal cyst, Jap. j. Dermat ., 88: 37-42,1978 (in Japanese). 10) Hino, Y.. Nishimura, M. and Koda, H.: Proliferating trichilemmal cyst. Nishmihon ]. Derm., 40: 259-267, 1978 (in Japanese).
