Acantholytic variant of squamous cell carcinoma of the breast

Acantholytic variant of squamous cell carcinoma (AVSCC) of the breast typically has pseudoglandular or pseudoangiosarcomatous histopathologic features due to marked dyscohesiveness of tumor cells which have dense squamoid cytoplasm. Tumor cells show immunoexpression for cytokeratin AE1/AE3, high molecular weight cytokeratin and p63, thus pertaining squamous characteristics. We present a typical case of AVSCC of the breast with preoperative metastasis to a sentinel lymph node and one-time recurrence. The tumor was predominantly composed of acantholytic component with minor contribution of patternless spindle cell component. Multifocal intraductal carcinomas were found within the tumor. Although some reports had mentioned about other breast cancers focally showing these characteristic features in usual invasive ductal carcinomas or metaplastic carcinomas, only nine cases have been collected as this recently defined entity since 1986. It is suggested that this tumor would be more aggressive than usual invasive ductal carcinomas based on the original report of three cases. However, additional cases of AVSCC often did not show dismal prognostic outcome. We present a typical case of AVSCC of the breast without critical progression of the disease for 38 months.