Sarcomatoid variant of anaplastic large cell lymphoma mimicking a primary breast cancer: A challenging diagnosis

Abstract

The sarcomatoid variant of anaplastic large cell lymphoma is one of the rarest histologic variants of this neoplasm. Due to its sarcomatoid features, it is frequently misdiagnosed as a poorly differentiated sarcoma, anaplastic carcinoma, or melanoma. We report the case of a 92-year-old woman with a sarcomatoid anaplastic large cell lymphoma mimicking a primary breast neoplasm. The patient presented with a rapidly enlarging lump in the left breast and nodules in the right axilla. The immunohistochemical profile showed reactivity for leukocyte common antigen, UCHL-1, vimentin, and CD30, but immunoexpression of anaplastic lymphoma kinase was lacking. Anaplastic large cell lymphomas are lymphoid neoplasms of T-cell/null-cell lineage that consistently express the activation marker CD30 and usually carry a gene rearrangement of the anaplastic lymphoma kinase gene. To the best of our knowledge, this is the first reported case of sarcomatoid anaplastic large cell lymphoma presenting as a primary breast neoplasm in which anaplastic lymphoma kinase expression was assessed.