Granulomatous lesions of the bone marrow in non-Hodgkin's lymphoma.

Granulomatous lesions were found in histologic sections of aspirated bone marrow in nine patients with non-Hodgkin's lymphoma. The lesions fell into three distinct histologic types. Type I, present in four patients, consisted of focal-to-diffuse lesions showing small lymphocytes intermingled with abundant benign epithelioid cells, occasionally forming discrete granulomas. Giant cells were prominent, some of which showed cytoplasmic inclusions of bony fragments. Many eosinophils and a few plasma cells were present. Type II, present in three patients, consisted of foci of malignant lymphoma containing collections of benign-appearing epithelioid cells forming discrete granulomas. Eosinophils and plasma cells were not prominent. Type III, found in two patients, showed discrete collections of small lymphocytes and histiocytes with an increased number of plasma cells, eosinophils, and megakaryocytes at the periphery. The significance of these lesions is discussed.