Sir.—I read with interest the article "Second Malignancy in Acute Lymphocytic Leukemia: Review of 33 Cases" by Drs Mosijczuk and Ruymann in the Journal (1981;135:313-316). In their article, they discussed the occurrence of histiocytic medullary reticulosis (HMR) after the diagnosis of acute lymphocytic leukemia (ALL). Histiocytic medullary reticulosis is a pattern of response to infection by a number of organisms.1,2 Although originally identified by Robb-Smith as one of the causes of HMR,3 acquired toxoplasmosis has been omitted from the list of possible causes of HMR in recent articles.
In the immunocompetent host, toxoplasmosis is a benign, self-limited illness that frequently resembles infectious mononucleosis in its clinical manifestations. However, in the immunosuppressed host, toxoplasmosis occurs as an acute, fulminating illness, with prominent systemic symptoms, hepatosplenomegaly, and, occasionally, signs of CNS dysfunction.4 If this diagnosis is not considered in an immunocompromised host, and appropriate therapy with pyrimethamine and