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

Abstract

Spiradenoma is a benign, morphologically well-defined cutaneous adnexal neoplasm that is closely related to cylindroma. We present the rare occurrence of adenoid cystic carcinoma (ACC)-like areas in 7 spiradenomas and 1 spiradenocylindroma, not described in the English literature to date. The ACC-like areas were a minor but significant component in all lesions and were usually multifocal and blended with the conventionally appearing parts of the neoplasms. The ACC-like areas were typified by cribriform formations of epithelial cells concentrically arranged around gland-like spaces filled with mucin, homogeneous eosinophilic material, or granular basophilic material. In some neoplasms, only mucin occurred in these pseudoglandular structures, whereas in other cases, a combination of all 3 secretory products was encountered. Although well-developed bilayered glands with a demonstrable peripheral myoepithelial cell layer were not recognizable in the ACC-like areas, immunohistochemistry demonstrated myoepithelial differentiation in these portions of the tumors. When present in the ACC-like areas, ductal structures manifested a rather squamoid lining, without a recognizable peripheral myoepithelial cell layer. It is concluded that the ACC-like pattern, although a rare feature and of no clinical consequence, is a distinctive finding in a minority of cases and extends the morphological spectrum of spiradenoma and spiradenocylindroma occurring sporadically or in the setting of Brooke-Spiegler syndrome. It represents a potential diagnostic pitfall, particularly in a limited biopsy specimen where the changes may be misdiagnosed as ACC.

Multiple (Familial) Trichoepitheliomas: A Clinicopathological and Molecular Biological Study, Including CYLD and PTCH Gene Analysis, of a Series of 16 Patients

“…Spiradenoma manifests on occasion features of follicular differentiation. 53,54 Conversely, spiradenoma-like areas may be encountered in other neoplasms showing variable differentiation along the lines of the folliculosebaceous-apocrine unit. 55 Thus, minor spiradenoma-like features in some of our TE cases are not remarkable.…”

A primary cutaneous adenoid-cystic carcinoma in a young woman. Differential diagnosis and clinical implications

“…8 Spiradenoma and spiroadenocylindroma can also have an adenoid cystic like pattern, as reported by Petersson and colleagues. 8,13 However, in these tumours this feature is always focal (maximum of 2.5 mm). For this reason a single punch biopsy of such lesions may be not representative for a definitive histological diagnosis.…”

“…All the mentioned lesions closely mimic the PCACC at histology. 8,12–13 The lack of basalioid cells disposed in peripheral palisades in an adenoid-cystic lesion without connection to the overlying epidermis help the distinction between a PCACC and the more common BCC adenoid-cystic type. 8 An other helpful histological feature for this differential diagnosis is the presence of artefactual clefts between tumour cells and stroma in BCC.…”

Large Germline Deletions of the CYLD Gene in Patients With Brooke–Spiegler Syndrome and Multiple Familial Trichoepithelioma

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] These cutaneous adnexal neoplasms may infrequently undergo malignant transformation. [15][16][17][18][19] Morphologically similar neoplasms may rarely arise in the salivary glands [20][21][22][23] and exceptionally in the breast.…”