Extensive histiocytosis masking anaplastic large-cell lymphoma (ALCL).

Abstract

HLH represents a severely uncontrolled hyperinflammatory reaction with numerous aetiologies including genetics, infection, autoimmune and malignancy. HLH is not itself a standalone pathological diagnosis, but rather a diagnosis based on integration of clinical and histological examination. Although malignancy-associated HLH (M-HLH) is seen commonly with lymphomas, HLH associated with ALCL is extremely rare. Diligent assessment of the histological tissue should be performed to identify the aetiology and not be distracted by the histiocytosis, likely caused by cytokines released from tumour cells.