Adenoid cystic carcinoma-like pattern in spiradenoma and spiradenocylindroma: a rare feature in sporadic neoplasms and those associated with Brooke-Spiegler syndrome

Am J Dermatopathol. 2009 Oct;31(7):642-8. doi: 10.1097/DAD.0b013e3181a1573e.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoma, Sweat Gland / pathology*
  • Aged
  • Carcinoma, Adenoid Cystic / pathology*
  • Diagnosis, Differential
  • Female
  • Humans
  • Male
  • Middle Aged
  • Sweat Gland Neoplasms / pathology*
  • Syndrome