A unique case of squamous cell carcinoma showing adenocarcinomatous features with focal apocrine differentiation

We report an 85-year-old man with squamous cell carcinoma on the right pinna. Two years after the excision of the lesion, metastatic foci were found extending from the right retromandibular to the mastoid region and into the parapharyngeal space. Histopathologically, the primary tumor showed interconnecting nests of atypical cells invading into the dermis from multiple epidermal and infundibular foci. The tumor had both squamous and glandular differentiation. A peculiar finding was the presence of decapitation secretion in the glandular foci. To our knowledge, definite apocrine differentiation in squamous cell carcinoma has not previously been reported.