Composite ALK-negative anaplastic large cell lymphoma and small lymphocytic lymphoma involving the right inguinal lymph node.

Anaplastic large cell lymphoma and small lymphocytic lymphoma are two lymphoid malignancies with completely distinct morphologies and natural histories. We present a rare case of composite anaplastic large cell lymphoma and small lymphocytic lymphoma in an inguinal lymph node of an otherwise healthy 47-year-old male patient. Immunohistochemical and molecular studies identified the two populations clearly. Their separation is imperative as anaplastic large cell lymphoma can be an aggressive neoplasm and easily overlooked in cases of small lymphocytic lymphoma with a small population of anaplastic large cell lymphoma cells.