Eccrine syringofibroadenoma associated with well-differentiated squamous cell carcinoma.

We report a case of an eccrine syringofibroadenoma (ESFA) associated with well-differentiated squamous cell carcinoma. The patient was an 85-year-old man, who had a 2.5x2.5-cm, brown-colored ulcerated nodule, with a fragile, flesh-colored bleeding surface located beyond the metacarpophalangeal joint of the second finger of his left hand. Histopathologically, there were areas of a well-differentiated squamous cell carcinoma, alternating with the typical area of ESFA characterized by anastomosing cords, strands, and columns of epithelial cells extending from the crusted epidermis into a thickened, edematous, myxoid vascular-rich dermis. Immunohistochemically, the areas with dysplastic epithelium were positive for p16, whereas the benign ESFA parts tested negative. Human papillomavirus was detected in the lesional tissue by polymerase chain reaction, and the subsequent sequencing analysis demonstrated that the virus was close to human papillomavirus type 107.