Faculty Bibliography

Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a rare cutaneous adnexal neoplasm typically arising on the face of older individuals, most commonly around the eyelids. Histopathologic features include a circumscribed proliferation of low-grade epithelioid cells with areas of cystic and cribriform growth, foci of intracytoplasmic and extracellular mucin, and coexpression of endocrine, neuroendocrine, and cytokeratin markers by immunohistochemistry. Given histopathologic and immunohistochemical similarities, EMPSGC is often likened to solid papillary carcinoma of the breast and endocrine ductal carcinoma in situ, and is thought by many to represent a forme fruste of mucinous carcinoma of the skin. To date, the vast majority of reported cases of EMPSGC have been described as having indolent behavior, with no cases of distant metastasis yet reported. Here we report a unique case of EMPSGC that recurred over several years following standard surgical excision and Mohs micrographic surgery, with subsequent metastasis to the parotid gland and axial skeleton.

The synchronous incidence of 2 different subtypes of melanoma is very rare. Desmoplastic melanoma (DM) can be a diagnostic challenge because of its frequent appearance as a dermal banal spindle cell proliferation. We present a case of a 30-year-old man who developed an irregular, purple, tender plaque measuring 2.5 cm on the right pretibial region. Wide excision of the right leg lesion showed superficial spreading melanoma with epithelioid cells and no spindle cell component. Sentinel lymph node (SLN) biopsy showed an atypical melanocytic proliferation involving one inguinal lymph node with subcapsular and intraparenchymal components. There were spindled tumor cells in lymph node capsule with hyperchromatic nuclei, which were nested within desmoplastic stroma, and were S100- and SOX10-positive and MART1- and HMB-45 negative; in addition to epithelioid tumor cells, which were S100-, SOX10-, and MART1-positive. Multiple discontinuous foci, subcapsular atypical melanocytes, and extracapsular extension helped in excluding capsular nevus. These findings were consistent with DM. Herein, we present an unusual case of primary cutaneous superficial spreading melanoma of the right leg with a predominantly epithelioid morphology that developed metastases to the SLN. The metastasis exhibited divergent differentiation, including both epithelioid morphology identical to the primary, but with additional features of DM that were nonoverlapping with the primary lesion.

Vulvar malignant melanoma (VMM), although uncommon, comprises 5-10% of all vulvar malignancies. Local control is notoriously poor in VMM with recurrence rates of 30-50% compared with approximately 3% in cutaneous melanomas. We studied clinicopathologic features of 37 women with VMM, after reviewing three decades of clinical follow-up data in our institutional databases. Most patients were Caucasian (n = 35) with an average age at diagnosis of 60.6 years (range 23-83). The most common subtype was mucosal lentiginous melanoma (n = 25). We compared Kaplan-Meier survival curves of 31 patients defined by clinical and microscopic attributes using exact log-rank tests. Younger patients at diagnosis (23-64 years), those with thin melanomas (≤1 mm), and those with Clark's level II or III tumors had better 5-year survival rates than older patients (65-83 years) and those with thick melanomas (>1 mm) and those with Clark's level IV or V (P ≤ 0.05), respectively, by exact log-rank test. Local recurrence of melanoma occurred in 15 patients. Nine patients (24%) had eventual urethral involvement by malignant melanoma, and this feature was associated with significantly shorter survival (P = 0.036). Patients with urethral involvement had shorter median time to death and worse 5-year survival rates. Given that spread to the urethra is common in VMM and urethral recurrence is also associated with mortality, pathology excision specimens should be carefully reviewed with attention to urethral involvement as a potentially important prognostic factor.

Sclerotic lipomas, a lipoma variant, are benign subcutaneous tumors, so-named because of their resemblance to sclerotic fibromas. Previous literature has suggested that these tumors may show a predilection for middle-aged adult males. We report an unusual case of a sclerotic lipoma diagnosed on the scalp of a 66-year-old female. The patient presented to the outpatient clinic with a 3- to 4-year history of an enlarging and irritated 2.6-cm nodule on the anterior crown of the scalp, clinically thought to be a pilar cyst. Histopathological examination from the excisional specimen revealed a well-circumscribed dermal to subcutaneous tumor with ample sclerotic collagen bundles, an increased number of CD34 positive spindled cells, and prominent S-100 positive mature adipocytes comprising greater than 50% of the tumor. We present this case given its atypical clinical and histopathological presentation, review the literature of sclerotic lipomas, and discuss the differential diagnosis to raise awareness of this rare entity.

BACKGROUND:Bullous pemphigoid (BP), the most common autoimmune blistering disease, may be diagnostically challenging. Direct immunofluorescence (DIF), indirect immunofluorescence (IIF), enzyme-linked immunosorbent assay (ELISA), and recently, C3d immunohistochemistry (IHC), are used as adjuncts to diagnosis. OBJECTIVE:To compare C3d IHC to DIF, IIF, and ELISA testing in BP diagnosis. METHODS:C3d IHC was performed on skin biopsy specimens from 51 patients (27 with BP and 24 with other blistering diseases) and compared to DIF and IIF, with anti-BP180 or anti-BP230 ELISA results used as the gold standard. RESULTS:We found C3d IHC, DIF, and IIF had similar sensitivity (74.1%, 63.1%, and 70.4%), specificity (95.8%, 100%, and 100%), positive predictive value (95.2%, 100%, and 100%), and negative predictive value (76.7%, 70.6%, and 75%) for BP. Cases with positive C3d IHC, DIF, and IIF had significantly higher anti-BP180 and anti-BP230 by ELISA than cases with negative testing (P < .0001). False-negative IIF results were associated with lower BP230 compared with true-positive results (P = .03). LIMITATIONS/CONCLUSIONS:This was a single-center, retrospective study. CONCLUSION/CONCLUSIONS:Our study compared C3d IHC to DIF and IIF in BP diagnosis, demonstrating C3d IHC on fixed tissue provides similar diagnostic utility to immunofluorescence and ELISA.