Cutaneous clear cell neoplasms: a systematic review

Neoplasms of the skin with clear cell morphology consist of a broad variety of primary and metastatic lesions with epithelial, mesenchymal and melanocytic differentiation. The clear cell changes are attributable to a variety of causes from artifact to accumulation of intracellular substances such as glycogen, mucin, and/or lipids. The clear cell morphology is easily identified by the pathologist, however is it not specific. Additional salient histologic findings may be subtle and therefore ancillary studies such as immunohistochemistry and molecular studies may be necessary to help elucidate a diagnosis. This review features cutaneous neoplasms characterized by clear cell changes, organized by histogenesis. It discusses the differential diagnosis of these lesions with a focus on helpful immunohistochemical and molecular studies which may aid in the clinicopathologic evaluation of these challenging lesions.