Neutrophil-rich anaplastic large cell lymphoma of the skull presenting after head trauma

The presentation of anaplastic large cell lymphoma in bone is uncommon. We report a case of anaplastic large cell lymphoma of the skull that was diagnosed after head trauma. Biopsy revealed significant destruction of the outer table of the frontal bone. Histopathologically, the initial evaluation suggested osteomyelitis because of a mixed inflammatory infiltrate with large numbers of neutrophils. However, several clusters and individual mononuclear cells were atypical. The tumor cells had large, pleomorphic nuclei; these cells stained positively with antibodies to Ki-1 (CD 30), ALK-1, and EMA. Fluorescence in situ hybridization (FISH) showed rearrangement of the ALK gene, which usually results from the t(2;5) translocation, present in most anaplastic large cell lymphomas. There was no evidence of systemic disease. The patient has tolerated chemotherapy and is free of disease 12 months later.