Malignant histiocytosis in childhood. Clinicopathological study of 4 cases.

Clinicopathological features of four paediatric cases of malignant histiocytosis (MH) are described. The patients all presented with fever, lymphadenopathy and anaemia. Two died from widespread disease within one month. Two patients, who received combination chemotherapy, were brought into remission and are currently without disease after 30 and 60 months, respectively. Diagnosis was made on the basis of infiltration by a mixture of anaplastic and well-differentiated phagocytic histiocytes in skin, lymph node, bone marrow and spleen. Immunohistochemical studies showed variable presence of lysozyme, alpha 1-antitrypsin (AT), and alpha 1-antichymotrypsin (ACT). Concanavalin A (Con A) receptors, recently suggested as a histiocyte marker, were found in the proliferating cells in all cases. S-100 protein was absent. The findings suggest that the prognosis in childhood MH remains guarded but not hopeless with aggressive combination chemotherapy. The presence of Con A receptors in paediatric MH cells with a more constant occurrence than lysozome, AT and ACT seems promising as an additional diagnostic tool although further studies are needed to examine the specificity of Con A receptors in relation to various other disorders of histiocytic proliferation.