Tumors of the skin composed of large cells with abundant eosinophilic cytoplasm.

Tumors of the skin composed of large epithelioid cells displaying abundant smooth or granular eosinophilic cytoplasm are relatively rare, yet may constitute a source of diagnostic difficulties for pathologists. Lesions derived from various skin elements are represented in this group, including tumors originating from adnexal structures and connective tissue elements of the dermis. The large, pink-cell or epithelioid appearance of the tumor cells may be the result of attempts to recapitulate the phenotype of a cell line normally characterized by such morphological appearance, such as apocrine epithelium, or may result from secondary changes in the cytoplasm of the tumor cells, such as accumulation of autophagosomes in granular cell tumors. The characteristic pathological features of this group of tumors is the subject of this review, with special emphasis on their differential diagnosis and the morphological features that may be of help for practicing pathologists to arrive at a correct diagnosis.