An unusual case of sarcomatoid alk negative anaplastic large cell lymphoma

Abstract

Anaplastic large cell lymphoma (ALCL) has a number of morphological variants that can pose diagnostic challenges. One of the rarest variants is the sarcomatoid variant, with the literature on this neoplasm limited to sporadic case reports. Sarcomatoid ALCL consists of large, often spindled neoplastic cells that can mimic a soft tissue sarcoma, anaplastic carcinoma or melanoma. This confusion may be confounded by the fact that many cases are anaplastic lymphoma kinase (ALK) negative. We report the case of a 66-year-old male presenting with multiple right axillary masses. A core biopsy of one of these revealed the normal nodal architecture to be effaced by a population of large, anaplastic epithelioid and spindled cells arranged in a vaguely fascicular and storiform architecture. Immunohistochemistry revealed the lesion to be strongly positive for CD30, as well as CD45. Positive staining was also seen with the T cell markers CD4 and CD7, as well as a number of cytotoxic markers. Following an expert opinion being sought, a diagnosis of ALK negative anaplastic large cell lymphoma with sarcomatoid morphology was rendered.