Abstract:

A 26-year-old male with a history of acute lymphocytic leukemia in remission after chemotherapy and allogenic stem cell transplant presented for an asymptomatic growth on the left index finger of two years duration. Physical examination demonstrated a pink papule with a collarette of scale on the dorsal left index finger. A shave biopsy demonstrated a hyperorthokeratotic and hyperplastic epidermis overlying an oblong fibrous core. There were numerous lesional fibroblasts which demonstrated pleomorphism, hyperchromatic nuclei, and floret shapes. These cells were negative for CD34 and highlighted with Factor XIIIa. Lesional mitotic figures were absent. The patient was diagnosed with an acquired digital fibrokeratomas (ADFK) with pleomorphic fibroma changes. ADFKs are acquired acral lesions often arising in the setting of trauma or inflammation. Histopathologically, they typically demonstrate a fibrous core with bland stellate spindled cells. The lesional cells typically highlight with factor XIIIa. The aforementioned pleomorphic fibroma-like changes have not been described before to our knowledge and through a comprehensive literature search. In pleomorphic fibromas, the atypical giant cells are highlighted with CD34 and variably positive for FXIIIa. Similar pleomorphic changes have been reported in other lesions including giant cell fibroblastomas, dermatofibromas, sclerotic fibromas, lipomas, and angiofibromas. The presence of pleomorphic fibroma-like changes documented in this ADFK are unique. The atypical features prompt consideration of more atypical neoplasms, however the lack of mitotic activity, bland architecture, and appropriate clinical appearance supports the diagnosis. Considering the clinical and histopathologic features together, we propose this lesion to be a new clinicopathologic entity: the pleomorphic acquired digital fibrokeratoma.

Financial Disclosure:
No current or relevant financial relationships exist.

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Leo Wang, MD, PhD