Composite lymphoma with immunoblastic features and Langerhans' cell granulomatosis (histiocytosis X).

A 50-year-old male with a history of tonsillar and right axillary lymph node enlargement due to atypical lymphoid hyperplasia presented two years later with marked bilateral axillary and inguinal lymphadenopathy. The lymph node biopsy showed a composite lymphoma (follicular, mixed, small and large cell plus B-immunoblastic sarcoma) with associated focal Langerhans' cell granulomatosis (LCG) (Histiocytosis X). The diagnosis of composite lymphoma was supported by the immunohistochemical demonstration of two different monoclonal patterns in the follicular and diffuse areas. The typical Birbeck's granules were demonstrated ultrastructurally in LCG areas, which also stained with S-100 protein. LCG may coexist with malignant lymphoma, however, it appears to be confined to the neoplastic nodes with no tendency to systemic spread. It is important to recognize this association so that the impact of this apparently benign lesion (LCG) not be overestimated and that the subsequent management of the patient be directed according to the type of the coexisting malignant lymphoma.