Premalignant Fibroepithelial Tumor (Pinkus Tumor) Workup

Updated: Feb 08, 2019
  • Author: Darius Mehregan, MD; Chief Editor: Dirk M Elston, MD  more...
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Workup

Procedures

The diagnosis can be easily confirmed by performing a skin biopsy.

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Histologic Findings

The classic fibroepithelioma of Pinkus typically shows long, thin, branching and anastomosing strands of basal cell carcinoma embedded in a loose fibrovascular stroma. Many strands show a connection with the epidermis. The basaloid strands show 2 distinct-appearing cells. A lighter staining cell comprises the bulk of the strand. Scattered, small groups of darker cells are seen tapering off the main trunk in a palisading arrangement like buds on a branch.

Nuclear pleomorphism may be present, and staining with proliferation markers such as Ki-67 shows an increased proliferative index. [16] Coexpression of androgen receptor, diffuse expression of Bcl-2, and the scattered presence of Merkel cells as marked by cytokeratin 20 may aid in the diagnosis of fibroepithelioma of Pinkus. [17] The tumor is superficial and well demarcated at its lower border. It bears strong histologic resemblance to reticulated seborrheic keratosis but lacks a typical horn and pseudohorn pearls. Hyperkeratosis is rarely present.

See the image below.

Basal cell fibroepithelioma (Pinkus tumor). Courte Basal cell fibroepithelioma (Pinkus tumor). Courtesy of L Wozniak & KW Zielinski (own work), via Wikimedia Commons.
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