English

Abstract

Rare group of tumors with potential for local destruction and metastasis, Taxonomically segregated into 2 main groups, as follows: those that are histologically similar to certain benign appendage tumors (e.g., sclerosing sweat duct carcinoma, porocarcinoma, malignant chondroid syringoma, malignant nodular hidradenoma, and malignant eccrine spiradenoma) and those that show a diverse array of histologic features, not recapitulating to any degree aspects of a benign counterpart derived de novo from any portion of the normal eccrine apparatus or result from the transformation of an existing benign eccrine tumor. An etiologic role for UVR has been suggested; Abbate et al reported that 5 out of 10 patients with MAC gave a prior history of radiation therapy. Chiller et al reported a potential etiologic role for UVR as they describe MAC predominantly affecting the left side of the face, corresponding to higher UVR exposures while driving. Immunosuppression has been known to increase the risk of nonmelanoma skin cancers, particularly squamous cell carcinomas, Harwood et al suggested that patients who are immunosuppressed have a propensity to also develop cutaneous appendageal tumors over their immunocompetent counterparts, with increased rates of both benign eccrine tumors and malignant eccrine tumors. REPORT OF A CASE: It is exceedingly rare, accounting for roughly 1 of 13,000 specimens submitted to a dermatopathology laboratory. The more common subtypes include microcystic adnexal carcinoma, eccrine porocarcinoma, and hidradenocarcinoma. The less common subtypes include eccrine mucinous carcinoma, malignant eccrine spiradenoma, malignant mixed tumor, malignant cylindroma, and papillary eccrine adenoma. Only several hundred cases of eccrine carcinoma have been reported in the literature worldwide. Many of these tumors metastasize (up to 60%), with a fatal outcome. MAC was previously only described in white patients; however, Peterson et al and Gardner et al reported the first and second cases of MAC affecting African Americans, respectively. Sex incidence would appear to be equal for eccrine carcinoma, although this has not been definitively stated. Exceptions to this are the malignant chondroid syringoma and primary cutaneous adenoid cystic eccrine carcinoma, both of which occur more commonly in females than in males. Eccrine carcinomas most commonly are diagnosed in patients in their fifth through eighth decades of life. Here we describe a unique and a rare case of malignant eccrine spiradenoma which mimicked like a basal cell carcinoma, squamous cell carcinoma or a malignant melanoma.