One was found to have intraductal breast carcinoma underlying fibroepithelioma of Pinkus and the other was found to have a perianal fibroepithelioma harboring Paget cells. The lesion is typically pink to red but may be pigmented. This tumor can clinically resemble seborrheic keratosis, pedunculated fibroma, nevus sebaceus of Jadassohn, papillomatous melanocytic nevus, amelanotic melanoma and neurofibroma. Whether any of these predisposing factors is a relevant cause of fibroepithelioma of Pinkus is unproven. The classic fibroepithelioma of Pinkus typically shows long, thin, branching, anastomosing strands of basal cell carcinoma embedded in a fibrovascular stroma.
Many strands show connection with the epidermis.
The basaloid strands show two distinct-appearing cells. There is a lighter staining cell comprising the bulk of the strand. The tumor is quite superficial and well demarcated at its lower border. It bears strong histologic resemblance to reticulated seborrheic keratosis but lacks typical horn and pseudohorn pearls. Hyperkeratosis is rarely present.