“Onycholemmal Carcinoma.” An Unusual Case With Apocrine and Sebaceous Differentiation. Are These Tumors a Microcystic Nail Bed Carcinoma?

Abstract

Subungual malignant epithelial tumors with tricholemmal keratinization have rarely been described as "malignant proliferating onycholemmal cyst" and "onycholemmal carcinoma (OC)." We 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. We 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, we 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. Therefore, the previous cases of OC without sebaceous-apocrine differentiation could be best classified as a microcystic nail bed carcinoma arising from the follicular microcysts of the nail bed, with a limited differentiation toward the keratinization of the follicular isthmus.

Nail Unit Squamous Cell Carcinoma with Onycholemmal Features: Case Report and Review of the Literature

“…Herein, we report a case of SCC of the nail unit with distinct features of the previously described variant, OC, presenting as a very rare slow-growing malignant tumor arising from nail bed epithelium [4]. Since it was first described by Alessi et al [4] in 2004, there have only been 15 previously reported cases in the English literature, which are summarized in Table 1 [1][2][3][4][5][6][7][8][9][10]. Previously reported cases of OC have presented with varying clinical manifestations.…”

Onycholemmal carcinoma with prominent dystrophic calcification and review of the literature

“…Recognition of this entity is important to ensure that appropriate, but not excessively aggressive, management is pursued. Among Cases with reported treatments, nine of thirteen (69%) lesions were treated by amputation or distal interphalangeal joint disarticulation . One lesion was managed with radiation, one with Mohs surgery, and two with more conservative re‐excisions .…”

“…Among cases with reported treatments, nine of thirteen (69%) lesions were treated by amputation or distal interphalangeal joint disarticulation. [1][2][3][4][5]7,10 One lesion was managed with radiation, one with Mohs surgery, and two with more conservative re-excisions. 1 To date, none of the reported cases have recurred locally.…”

“…Since its initial description in 2004, approximately thirteen cases have been reported in the English‐language literature . These cases are summarized in Table .…”

Onycholemmal carcinoma: A case report with its molecular profiling

“…Onycholemmal carcinoma (OC), also called microcystic nail bed carcinoma, is a slow‐growing malignant epithelial tumor originating from the nail bed epithelium. Since the first description by Alessi et al only 12 other cases have been described in the English literature …”