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Malignant Proliferating Trichilemmal Tumor Treated With Mohs Surgery: Proposed Protocol for Diagnostic Work-up and Treatment
Proliferating trichilemmal tumors (PTT) are benign neoplasms, most commonly of the scalp, that are thought to arise from pilar cysts. Rarely, malignant transformation can occur (malignant proliferating trichilemmal tumors [MPTT]).1 Because of the rarity of this tumor, there are no standardized diagnostic and treatment protocols available. Herein, the authors report a case of MPTT successfully treated with Mohs surgery and propose a protocol for diagnostic workup and treatment based on information available from previous reports. A 67-year-old white man presented for evaluation of a painful nodule on the right frontal scalp. The nodule had increased in size rapidly over the past 3 months. Clinical examination revealed a 2.5-cm tender subcutaneous nodule. It had a conical shape, and telangiectasias were developing on the overlying skin. Conservative excision was performed. When the lesion was encountered in the subcutaneous plane, a friable and infiltrating tumor with areas of gross necrosis was found. The majority of the tumor mass was dissected and excised, but because of the amorphous nature of the lesion, the extent of the tumor margin was unclear. Histopathologically, portions of the tumor showed features of a PTT (Figure 1). However, large portions of the lesion showed high-grade nuclear atypia with atypical infiltrating islands of keratinocytes, some showing islands of necrosis. Atypical mitotic figures were noted (Figures 2 and 3). Ki-67 stain showed an increase in proliferation, and the PHH3 stain showed a high number of mitotic figures. Pathologic diagnosis of MPTT was established. The tumor was present at all margins. Repeat clinical examination 2 weeks after the excision revealed increasing erythema and induration surrounding the excision site. There was no palpable
292
lymphadenopathy in the head, neck, supraclavicular, or axillary nodal basins. Computed tomography (CT) with contrast of the head and soft tissue neck was ordered. Imaging revealed a soft-tissue mass in the right frontal scalp, but there was no evidence of extension into the underlying calvarium or pathologically enlarged lymph nodes. The authors elected to excise the MPTT using Mohs micrographic surgery. A tumor-free plane was reached after the first stage. The final defect was 3.0 · 2.5 cm and extended to periosteum. The defect was repaired primarily. At a 6-month follow-up, the site was well healed and there was no evidence of recurrence. Discussion Proliferating trichilemmal tumors are histologically characterized by an abrupt transition of the nucleated epithelium to anucleated keratinized cells without a granular layer. Malignant proliferating trichilemmal tumors show more aggressive clinical and biologic behavior as well as atypical histologic features. There is some debate as to the distinction between benign versus malignant variants of PTTs. This has been reviewed elsewhere.1 The tumor in the authors’ patient was deemed malignant because of its rapid clinical growth and aggressive histopathologic features: infiltrating tumor borders, high mitotic rate, atypical mitoses, areas of necrosis, and high-grade nuclear atypia. This is consistent with the definition of high-grade MPTT as proposed in the pathology literature.2 Two small series reported the metastatic rate of MPTTs to be 25%.2 Because of this, radiographic evaluation is imperative once the diagnosis has been established. Head CT with contrast is the modality of choice to evaluate for local bony involvement and erosion. Computed tomography of the neck can be used to assess for regional and nodal metastases
DERMATOLOGIC SURGERY
© 2015 by the American Society for Dermatologic Surgery, Inc. Published by Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
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Figure 1. Proliferative neoplasm with trichilemmal keratinization without a granular layer, features consistent with PTT. This type of keratinization is not seen in squamous cell carcinoma, which would be considered in the differential diagnosis (hematoxylin and eosin, ·25).
Figure 3. Higher-power view showing infiltrating islands of keratinocytes, necrosis of the tumor, and pleomorphic nuclear atypia. These features support the diagnosis of MPTT (hematoxylin and eosin, ·40).
along the skull base and neck. Magnetic resonance imaging is more appropriate to assess soft-tissue infiltration or involvement of the dural sinuses. A solid or cystic mass with poorly defined margins and penetration of tissue planes may be identified. Findings suggestive of malignancy include local invasion into the calvarium, meninges, or dural sinuses. Other malignant characteristics include enhancement of the soft-tissue components along the borders of the tumor and infiltration of the surrounding soft tissues.3 Systemic work-up should be initiated if there is suggestion of local or regional spread. Whole-body
positron emission tomography scanning should be used.
Figure 2. Portions of the neoplasm revealing infiltrating islands of tumor cells, islands of necrosis, and pleomorphic nuclear atypia. These features would not be seen in a typical trichilemmal cyst (hematoxylin and eosin, ·25).
Surgical excision is the mainstay of treatment for MPTTs. Traditionally, wide excision with at least 1-cm margins has been recommended.1 However, local recurrence rate is high even for benign PTTs, reported at 3.7%.2 Mohs micrographic surgery has been reported to be a successful technique for treating trichilemmal tumors, although most cases have involved the benign variant.4 Because these tumors often have indistinct margins and borders that penetrate widely, Mohs surgery is indicated. It offers superior margin control and also provides tissue-sparing benefit for these frequently large lesions. This is especially important in the malignant form of these tumors because it may prevent future metastatic spread.1 Various adjuvant treatment regimens have been used for MPTTs with local, regional, and distant metastatic spread. Meta-analysis of 185 patients in 8 series revealed many poor outcomes in patients who did not receive any adjuvant therapies. Nodal dissection is typically deemed necessary if head and neck lymph node metastases are present. The role of radiation therapy is not entirely clear. However, given the aggressive nature of MPTTs, adjuvant radiotherapy is justified in many cases.5 Chemotherapy is considered in cases with distant metastases. The CAV regimen (cisplatin, Adriamycin, and vindesine) has been used in a manner similar to the
41:2:FEBRUARY 2015
© 2015 by the American Society for Dermatologic Surgery, Inc. Published by Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
293
LETTERS AND COMMUNICATIONS
method used for advanced squamous cell carcinoma. This has been met with limited success.1
References
In summary, the authors propose that Mohs surgery is an effective and tissue-sparing approach for MPTTs. Wide local excision with 1-cm margins may also be considered, but Mohs provides superior margin evaluation that is extremely important in tumors with infiltrative borders such as MPTT. All cases of MPTT should at minimum be evaluated with local imaging to assess the extent of local involvement and investigate for regional metastases. Computed tomography with contrast of the head and neck seems to be appropriate for scalp tumors. Any suspicion for metastases should prompt systemic work-up including a positron emission tomography scan. Radiation therapy and/or chemotherapy may be considered in some cases. Patients should be followed closely with frequent examinations to evaluate for the possibility of recurrence or metastases.
2. Ye J, Nappi O, Swanson P, Petterson J, et al. Proliferating pilar tumors. A clinicopathologic study of 76 cases with a proposal for definition of benign and malignant variants. Am J Clin Pathol 2004; 122:566–74.
1. Satyaprakash A, Sheehan D, Sangueza O. Proliferating trichilemmal tumors: a review of the literature. Dermatol Surg 2007;33:1102–8.
3. Chang S, Sims J, Murtagh F, McCaffrey J, et al. Proliferating trichilemmal cysts of the scalp on CT. AJNR Am J Neuroradiol 2006;27:712–4. 4. Behroozan D, Goldberg L, Glaich A, Kaplan B, et al. Mohs micrographic surgery for deeply penetrating expanding benign cutaneous neoplasms. Dermatol Surg 2006;32:958–65. 5. Siddha M, Budrukkar A, Shet T, Deshpande M, et al. Malignant pilar tumor of the scalp: a case report and review of literature. J Cancer Res Ther 2007;3:240–3.
David R. Fieleke, MD Glenn D. Goldstein, MD Dermatology and Skin Cancer Center Leawood, Kansas The authors have indicated no significant interest with commercial supporters.
Use of 2-Octyl Cyanoacrylate to Obviate Daily Wound Care After Mohs Surgery
Wounds left to heal by secondary intention after Mohs micrographic surgery can present a challenge for the patient in terms of wound care and length of time for complete healing. There are few documented alternatives to daily wound care for such wounds. The authors report the use of a topical skin adhesive, 2-octyl cyanoacrylate (Dermabond Advanced; Ethicon US, Somerville, NJ), on open wounds created by Mohs micrographic surgery in a patient with limited wound care ability. Prior reports using 2-octyl cyanoacrylate for wound healing after Mohs surgery have evaluated cosmetic results, with comparable or equivalent outcomes to suturing,1,2 but without consideration for the patients’ functionality. M.F. is an 88-year-old man who has a history of multiple melanomas, squamous cell carcinomas, and basal cell carcinomas. His medical history is significant for pacemaker placement, cerebrovascular
294
accident last year, atrial fibrillation, and Type II diabetes. His medications include aspirin and warfarin with notable difficulty in controlling his international normalized ratio. Previous Mohs procedures have been complicated by significant bleeding at wound sites, and sites left to heal by secondary intention on the lower extremities were complicated by prolonged healing time (greater than 5 months) and infection. The patient is retired and lives alone; his mobility is impaired, and thus, wound care has been a significant challenge for him.
Technique The patient presented with ill-defined squamous cell carcinomas on the elbow, lateral knee, and shin. Before Mohs micrographic surgery, the patient reiterated that he lives alone and that he has had trouble with wound healing and care in the past. His INR before the procedures was 2.8. The elbow was
DERMATOLOGIC SURGERY
© 2015 by the American Society for Dermatologic Surgery, Inc. Published by Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
Malignant Proliferating Trichilemmal Tumor Treated With Mohs Surgery: Proposed Protocol for Diagnostic Work-up and Treatment
Proliferating trichilemmal tumors (PTT) are benign neoplasms, most commonly of the scalp, that are thought to arise from pilar cysts. Rarely, malignant transformation can occur (malignant proliferating trichilemmal tumors [MPTT]).1 Because of the rarity of this tumor, there are no standardized diagnostic and treatment protocols available. Herein, the authors report a case of MPTT successfully treated with Mohs surgery and propose a protocol for diagnostic workup and treatment based on information available from previous reports. A 67-year-old white man presented for evaluation of a painful nodule on the right frontal scalp. The nodule had increased in size rapidly over the past 3 months. Clinical examination revealed a 2.5-cm tender subcutaneous nodule. It had a conical shape, and telangiectasias were developing on the overlying skin. Conservative excision was performed. When the lesion was encountered in the subcutaneous plane, a friable and infiltrating tumor with areas of gross necrosis was found. The majority of the tumor mass was dissected and excised, but because of the amorphous nature of the lesion, the extent of the tumor margin was unclear. Histopathologically, portions of the tumor showed features of a PTT (Figure 1). However, large portions of the lesion showed high-grade nuclear atypia with atypical infiltrating islands of keratinocytes, some showing islands of necrosis. Atypical mitotic figures were noted (Figures 2 and 3). Ki-67 stain showed an increase in proliferation, and the PHH3 stain showed a high number of mitotic figures. Pathologic diagnosis of MPTT was established. The tumor was present at all margins. Repeat clinical examination 2 weeks after the excision revealed increasing erythema and induration surrounding the excision site. There was no palpable
292
lymphadenopathy in the head, neck, supraclavicular, or axillary nodal basins. Computed tomography (CT) with contrast of the head and soft tissue neck was ordered. Imaging revealed a soft-tissue mass in the right frontal scalp, but there was no evidence of extension into the underlying calvarium or pathologically enlarged lymph nodes. The authors elected to excise the MPTT using Mohs micrographic surgery. A tumor-free plane was reached after the first stage. The final defect was 3.0 · 2.5 cm and extended to periosteum. The defect was repaired primarily. At a 6-month follow-up, the site was well healed and there was no evidence of recurrence. Discussion Proliferating trichilemmal tumors are histologically characterized by an abrupt transition of the nucleated epithelium to anucleated keratinized cells without a granular layer. Malignant proliferating trichilemmal tumors show more aggressive clinical and biologic behavior as well as atypical histologic features. There is some debate as to the distinction between benign versus malignant variants of PTTs. This has been reviewed elsewhere.1 The tumor in the authors’ patient was deemed malignant because of its rapid clinical growth and aggressive histopathologic features: infiltrating tumor borders, high mitotic rate, atypical mitoses, areas of necrosis, and high-grade nuclear atypia. This is consistent with the definition of high-grade MPTT as proposed in the pathology literature.2 Two small series reported the metastatic rate of MPTTs to be 25%.2 Because of this, radiographic evaluation is imperative once the diagnosis has been established. Head CT with contrast is the modality of choice to evaluate for local bony involvement and erosion. Computed tomography of the neck can be used to assess for regional and nodal metastases
DERMATOLOGIC SURGERY
© 2015 by the American Society for Dermatologic Surgery, Inc. Published by Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
LETTERS AND COMMUNICATIONS
Figure 1. Proliferative neoplasm with trichilemmal keratinization without a granular layer, features consistent with PTT. This type of keratinization is not seen in squamous cell carcinoma, which would be considered in the differential diagnosis (hematoxylin and eosin, ·25).
Figure 3. Higher-power view showing infiltrating islands of keratinocytes, necrosis of the tumor, and pleomorphic nuclear atypia. These features support the diagnosis of MPTT (hematoxylin and eosin, ·40).
along the skull base and neck. Magnetic resonance imaging is more appropriate to assess soft-tissue infiltration or involvement of the dural sinuses. A solid or cystic mass with poorly defined margins and penetration of tissue planes may be identified. Findings suggestive of malignancy include local invasion into the calvarium, meninges, or dural sinuses. Other malignant characteristics include enhancement of the soft-tissue components along the borders of the tumor and infiltration of the surrounding soft tissues.3 Systemic work-up should be initiated if there is suggestion of local or regional spread. Whole-body
positron emission tomography scanning should be used.
Figure 2. Portions of the neoplasm revealing infiltrating islands of tumor cells, islands of necrosis, and pleomorphic nuclear atypia. These features would not be seen in a typical trichilemmal cyst (hematoxylin and eosin, ·25).
Surgical excision is the mainstay of treatment for MPTTs. Traditionally, wide excision with at least 1-cm margins has been recommended.1 However, local recurrence rate is high even for benign PTTs, reported at 3.7%.2 Mohs micrographic surgery has been reported to be a successful technique for treating trichilemmal tumors, although most cases have involved the benign variant.4 Because these tumors often have indistinct margins and borders that penetrate widely, Mohs surgery is indicated. It offers superior margin control and also provides tissue-sparing benefit for these frequently large lesions. This is especially important in the malignant form of these tumors because it may prevent future metastatic spread.1 Various adjuvant treatment regimens have been used for MPTTs with local, regional, and distant metastatic spread. Meta-analysis of 185 patients in 8 series revealed many poor outcomes in patients who did not receive any adjuvant therapies. Nodal dissection is typically deemed necessary if head and neck lymph node metastases are present. The role of radiation therapy is not entirely clear. However, given the aggressive nature of MPTTs, adjuvant radiotherapy is justified in many cases.5 Chemotherapy is considered in cases with distant metastases. The CAV regimen (cisplatin, Adriamycin, and vindesine) has been used in a manner similar to the
41:2:FEBRUARY 2015
© 2015 by the American Society for Dermatologic Surgery, Inc. Published by Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
293
LETTERS AND COMMUNICATIONS
method used for advanced squamous cell carcinoma. This has been met with limited success.1
References
In summary, the authors propose that Mohs surgery is an effective and tissue-sparing approach for MPTTs. Wide local excision with 1-cm margins may also be considered, but Mohs provides superior margin evaluation that is extremely important in tumors with infiltrative borders such as MPTT. All cases of MPTT should at minimum be evaluated with local imaging to assess the extent of local involvement and investigate for regional metastases. Computed tomography with contrast of the head and neck seems to be appropriate for scalp tumors. Any suspicion for metastases should prompt systemic work-up including a positron emission tomography scan. Radiation therapy and/or chemotherapy may be considered in some cases. Patients should be followed closely with frequent examinations to evaluate for the possibility of recurrence or metastases.
2. Ye J, Nappi O, Swanson P, Petterson J, et al. Proliferating pilar tumors. A clinicopathologic study of 76 cases with a proposal for definition of benign and malignant variants. Am J Clin Pathol 2004; 122:566–74.
1. Satyaprakash A, Sheehan D, Sangueza O. Proliferating trichilemmal tumors: a review of the literature. Dermatol Surg 2007;33:1102–8.
3. Chang S, Sims J, Murtagh F, McCaffrey J, et al. Proliferating trichilemmal cysts of the scalp on CT. AJNR Am J Neuroradiol 2006;27:712–4. 4. Behroozan D, Goldberg L, Glaich A, Kaplan B, et al. Mohs micrographic surgery for deeply penetrating expanding benign cutaneous neoplasms. Dermatol Surg 2006;32:958–65. 5. Siddha M, Budrukkar A, Shet T, Deshpande M, et al. Malignant pilar tumor of the scalp: a case report and review of literature. J Cancer Res Ther 2007;3:240–3.
David R. Fieleke, MD Glenn D. Goldstein, MD Dermatology and Skin Cancer Center Leawood, Kansas The authors have indicated no significant interest with commercial supporters.
Use of 2-Octyl Cyanoacrylate to Obviate Daily Wound Care After Mohs Surgery
Wounds left to heal by secondary intention after Mohs micrographic surgery can present a challenge for the patient in terms of wound care and length of time for complete healing. There are few documented alternatives to daily wound care for such wounds. The authors report the use of a topical skin adhesive, 2-octyl cyanoacrylate (Dermabond Advanced; Ethicon US, Somerville, NJ), on open wounds created by Mohs micrographic surgery in a patient with limited wound care ability. Prior reports using 2-octyl cyanoacrylate for wound healing after Mohs surgery have evaluated cosmetic results, with comparable or equivalent outcomes to suturing,1,2 but without consideration for the patients’ functionality. M.F. is an 88-year-old man who has a history of multiple melanomas, squamous cell carcinomas, and basal cell carcinomas. His medical history is significant for pacemaker placement, cerebrovascular
294
accident last year, atrial fibrillation, and Type II diabetes. His medications include aspirin and warfarin with notable difficulty in controlling his international normalized ratio. Previous Mohs procedures have been complicated by significant bleeding at wound sites, and sites left to heal by secondary intention on the lower extremities were complicated by prolonged healing time (greater than 5 months) and infection. The patient is retired and lives alone; his mobility is impaired, and thus, wound care has been a significant challenge for him.
Technique The patient presented with ill-defined squamous cell carcinomas on the elbow, lateral knee, and shin. Before Mohs micrographic surgery, the patient reiterated that he lives alone and that he has had trouble with wound healing and care in the past. His INR before the procedures was 2.8. The elbow was
DERMATOLOGIC SURGERY
© 2015 by the American Society for Dermatologic Surgery, Inc. Published by Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
