Myoepithelial differentiation in benign sweat gland tumors

Abstract

One hundred and two cases of benign sweat gland tumors of the skin were studied for the presence of myoepithelial cells specifically identified by a monoclonal antibody to alpha-smooth muscle actin on paraffin-embedded tissues. The monoclonal antibody gave a positive result in 12 of 12 cases of cylindroma, 14 of 16 cases of spiradenoma, 2 of 2 cases of apocrine tubular adenoma (papillary eccrine adenoma), 5 of 5 cases of apocrine hidrocystoma, 5 of 5 cases of hidradenoma papilliferum, and in 10 of 10 cases of syringocystadenoma papilliferum. Rare myoepithelial cells were detected in only 1 of 10 cases of mixed tumor, apocrine type. There was no immunoreactivity for alpha-smooth muscle actin in eccrine hidrocystoma (2 cases), mixed tumor of eccrine type (2 cases), syringoma (7 cases), hidroacanthoma simplex (1 case), eccrine poroma (14 cases), clear cell hidradenoma (15 cases), and in 1 case of eccrine syringofibroadenoma. Our data support the concept that myoepithelial cells are seen in most sweat gland tumors considered to differentiate toward the secretory coil of the normal sweat gland. In contrast, myoepithelial cells are absent in tumors showing differentiation toward the excretory (ductal) component of the gland.

Expression of Stem-Cell Markers (Cytokeratin 15 and Nestin) in Primary Adnexal Neoplasms-Clues to Etiopathogenesis

“…Their series also confirmed the observation that myoepithelial cells are seen in the CK15+ and/or nestin+ benign adnexal neoplasm in our study. 33 Evidence of myoepithelial differentiation in cutaneous mixed tumor, 34 hidradenoma papilliferum, 35 apocrine hidrocystoma, 36 spiradenoma, 33,37-39 and cylindroma 38,40 has been documented by either smooth muscle actin/S-100 protein immunohistochemical stains or ultrastructural studies and definitively speaks in favor of an apocrine origin in these studies. Nestin has been shown to be expressed in the basal/myoepithelial layer of the mammary gland.…”

Skin type spiradenoma of the parotid gland with malignant transformation

“…The latter variant is noteworthy because spiradenocarcinomas with an adenocarcinomatous component display highly atypical glands, some surrounded by an intact myoepithelial layer [45]. Myoepithelial differentiation in cutaneous spiradenoma is often detected immunohistochemically [46,47], but authentic glands with well-developed myoepithelial cells are extremely rare [48,45]. Malignant transformation of spiradenoma has also been reported in the breast [49,50].…”

Adenoid Cystic Carcinoma-Like Pattern in Spiradenoma and Spiradenocylindroma: A Rare Feature in Sporadic Neoplasms and Those Associated With Brooke-Spiegler Syndrome

“…3,4 Myoepithelial cells, although commonly encountered in classical spiradenoma and spiradenocylindroma, are not evident at the light microscopic level, but they are convincingly demonstrated by electron microscopy and immunohistochemistry. [5][6][7][8][9] Further morphologic variations include squamous, mucinous, and clear cell differentiation. Malignant transformation results in distinctive appearances including patterns resembling basal cell adenocarcinoma of the salivary gland, either low grade or high grade, infiltrating adenocarcinoma, or sarcomatoid (metaplastic) carcinoma.…”