Bone marrow involvement in systemic ALK+ anaplastic large cell lymphoma: morphological resemblance with Hodgkin's lymphoma.

A 21 years old male presented with enlarged cervical lymph nodes. Diagnosis of anaplastic large cell lymphoma was made on lymph node biopsy and confirmed by immunohistochemistry using a panel of monoclonal antibodies including ALK-1. Bone marrow aspiration revealed the presence of large lymphoma cells and trephine biopsy showed interstitial involvement. In addition, there was presence of binucleate cells, lymphocytes, plasma cells and eosinophils. All these features resulted in a strong resemblance of the morphology with Hodgkin's lymphoma.