“Onycholemmal Carcinoma.” An Unusual Case With Apocrine and Sebaceous Differentiation. Are These Tumors a Microcystic Nail Bed Carcinoma
The American Journal of Dermatopathology, 07/05/2012
Perrin C et al. – The authors report an additional case of a slow growing OC occurring on the middle finger of a 58–year–old man, which was unusual as it showed sebaceous–apocrine differentiation, in addition to a nail bed carcinoma with tricholemmal microcysts. The authors therefore consider the descriptive term of microcystic nail bed carcinoma more appropriate than OC. It is recognized that none of the rare cases of OC meet the classical additional criteria proposed by Headington for tricholemmal carcinoma, that is, lobular arrangement, peripheral palisading, thickened basement membrane, and glycogen–positive tumors cells. On the other hand, the authors suggest that the term follicular microcysts of the nail bed should be retained to describe the true nature of subungual epidermoid inclusions, which show usually a limited differentiation toward the follicular isthmus.