Low-grade Hidradenocarcinomas: A Clinicopathologic Study of an Unusual Carcinoma That Can Mimic its Benign Counterpart.

Hidradenocarcinomas are rare cutaneous adnexal malignancies with sweat gland differentiation that can show a broad spectrum of histomorphologic appearances, ranging from low to high grade. The diagnosis of low-grade hidradenocarcinoma can be challenging and may be mistaken for benign hidradenomas, especially on superficial and partial samples. We performed a retrospective analysis of 16 low-grade hidradenocarcinomas, obtained from 4 large academic institutions. All neoplasms presented clinically as nodular lesions that ranged in size from 1.5 to 6.0 cm. All patients were adults and their age ranged from 33 to 74 years of age. All cases shared features similar to hidradenomas in the surface and mid portion of the tumors and all tumors had 1 or more histomorphologic clues to malignancy, including the presence of an asymmetric and infiltrative growth pattern (especially at the base of the tumors), perineurial invasion, and a desmoplastic stromal reaction. In the tumors evaluated for immunohistochemistry, the tumor cells were positive for p63, EMA, AE1/AE3, MNF116, and CK7. Three patients underwent sentinel lymph node biopsy, and 2 cases showed metastatic disease to regional lymph nodes. All cases (including the 2 cases that had regional lymph node metastasis), showed no local recurrence or distant metastasis observed after a complete re-excision of the tumors (follow-up range from 6 to 72 mo). Our study highlights the salient clinical and histopathologic features of low-grade hidradenocarcinomas and emphasizes the potential diagnostic pitfalls in distinguishing this entity from other neoplasms. Our results indicate that a combination of thorough histopathologic inspection is necessary to support the diagnosis of this rare neoplasm. These tumors can be exceedingly difficult to diagnose and awareness of the subtle features of low-grade hidradenocarcinoma is of importance are as it remains a diagnostic challenge for practicing pathologists.

An update on Epstein-Barr virus-and human T-lymphotropic virus type-1-induced cutaneous manifestations. CME Part II.

The Epstein-Barr virus (EBV) is a DNA virus that infects 90% of the human population, is responsible for certain cutaneous lymphomas (extranodal NK/T-cell lymhoma, hydroa vacciniforme lymphoproliferative disorder, lymphomatoid granulomatosis, others), and can be associated with a variety of cutaneous manifestations (eg, infectious mononucleosis, severe mosquito bite allergy, chronic active EBV disease, Gianotti-Crosti syndrome). EBV-related skin disorders are frequent in certain populations (South and Cental America, Africa, Asia, and Oceania) and can be diagnostically challenging. The human T-lymphotropic virus type-1 is a retrovirus, which is known to be associated with adult T-cell leukemia/lymphoma, neurologic disorders, but also cutaneous non-neoplastic manifestations (infective dermatitis, infections, and infestations). We performed an updated revision of the clinical dermatologic and histopathologic findings associated with the cutaneous non-neoplastic and preneoplastic disorders occurring in association with the EBV and human T-lymphotropic virus type-1.