Verrucous carcinoma of the axilla: case report and review

Background: Verrucous carcinoma, a variant of squamous cell carcinoma, is distinct from squamous cell carcinoma in morphology and behavior. It preferentially occurs on the oropharyngeal mucosa, the urogenital mucosa, and the soles. In contrast to its malignant clinical picture, the tumor grows locally invasive but is histologically benign and metastasizes rarely. Methods: We report the uncommon occurrence of a large verrucous carcinoma on apparently uninvolved skin in the right axilla in a 47-year-old male. Results: Histologic examination reveals a cauliflower-like tumor consisting of deep invaginated epidermal proliferation with rabbit burrow-like, keratin-filled sinus formations; the basement membrane, however, remains intact. Immunohistology showed positivity for pancytokeratin (KL-1) and cytokeratin (CK) 18 and negativity for CK7, and assessment of the proliferative activity of the tumor cells revealed low percentage of Ki-67 expression. Furthermore, there were only scattered cells expressing p53 or bcl-2. Polymerase chain reaction excluded the presence of human papillomavirus. After complete excision, no signs of recurrence occurred over a follow-up period of three years. Conclusion: Verrucous carcinoma should be distinguished from typical squamous cell carcinoma. The clinicopathological features, differential diagnosis, and therapy are discussed here together with the molecular biologic aspects of the tumor.