Adenosquamous carcinoma of the skin: a case series.

BACKGROUND Adenosquamous carcinoma is an uncommon cutaneous malignant neoplasm with mixed glandular and squamous differentiation and a propensity for aggressive clinical behavior. OBSERVATIONS Of 27 patients diagnosed as having adenosquamous carcinoma, 19 were men and 5 were immunosuppressed. The mean age was 74 years. The majority of tumors were located on the face and scalp (19 of 27 [70%]) or upper extremity (4 of 27 [15%]). Squamous and glandular differentiation was characteristic. Thickness of the primary lesion ranged from 1.2 to 9.2 mm, with all tumors extensively invading the reticular dermis. Perineural invasion was seen in 4 of 27 primary cases (15%). Although 3 of 6 patients treated with Mohs micrographic surgery had subsequent locoregional recurrences, there was no evidence of distant metastasis after a mean of 2.3 years of patient follow-up. CONCLUSIONS Adenosquamous carcinoma is best considered as a locally aggressive high-risk subtype of cutaneous squamous cell carcinoma. Tumor thickness and perineural invasion are high-risk histopathological attributes, and immunosuppression is an important clinical risk factor. Although Mohs micrographic surgery may be the best initial treatment, locoregional recurrence is common.