Tubular apocrine adenoma with perineural invasion.

A tumor is reported that had remarkable pathologic changes showing with light microscopy a pattern in some portions consistent with tubular apocrine adenoma, while other areas were suggestive of syringoid eccrine carcinoma. Perineural invasion, commonly seen in syringoid eccrine carcinoma and never before reported in tubular apocrine adenoma, was found. Electron microscopy revealed the true apocrine nature of the tumor even though the tissue had been stored for 2 months in buffered formalin prior to processing.