45 8 Unusual Computed Tomographic Presentation of Cerebral Toxoplasmosis Sergio Mazer ,' Joao Candido Araujo, 2 Raul Correia Ribeiro,3 and Gilda Kasting4 The computed tomog r aphic appearance of three cases of cerebral toxoplasmosis is described. Two of the patients were children with Hodgkin disease and the third was an adult with syst emic lupus erythematosus . All patients were severely im- munosuppressed . Computed tomography showed single or mul- tiple hypodense rounded areas with peripheral annular contrast enhancement , suggesting pyogenic cerebral abscesses . Patho- logic correlation is presented. The importance of di agnosis and early treatment is emphasized . Toxoplasmosis is a protozoan infection produ ced by Toxoplasma gondii , which may be eith er co ngenital or acquired. Acute infec tion of th e ce ntr al nervous system has been report ed with in creas in g frequency in immunosuppressed pati ent s [ 1-4], particula rl y in those with neop lasms of the hematopoietic system [5, 6]. Several types of lesions of the central nervous system have been desc ribed un de r these c ircumstances, including " mass lesions" demonstr ated by co mputed tomography (CT) [ 7-9]. This paper reports two cases with similar eT findings diagnosed postmortem and a thir d case successfully tr eated. Case Reports Ca se 1 A 9-year-old boy with a hard mass in his right axilla and several small cervica l and inguinal lymph nodes had a diagnosis of Hodgkin disease established by biopsy of one of the cervica l lesions. Tr eat- ment with mechl ore thamine, Onco vin , proca rbazine, and predni- sone (MOPP) was started. Nine months later he returned with headache, do uble vision, vomiting, and drowsiness. Ne urologic examination showed papilledema, right VI nerve palsy, and left central f acial weak ness. Routine laboratory tests were unremarka- ble. eT showed two round lesions with ringlike co ntrast enhancement surrounded by edema, one in each ce rebral hemisphere (fi gs . 1 A and 1 B). Ten days later ano th er eT stu dy revealed enlar ge men t of both lesions and a small left thalami c nodule. IgM and IgG immu- nofluorescence antib ody tests f or toxoplasmosis were nega ti ve. Biop sy of the right parietal lesion showed nonspecific inflammatory ti ssue. Neurologic status progre ssively de teriorated, and the patient died. At autopsy, a right parietal hematoma was found at the site of biopsy. Posteri or to the hematoma a nodular gray lesion was iden- tified. Microsco pic examination revealed a mononuclear infiltrate and pseud ocysts co ntaining Toxoplasma gondii tro phozoites (fig. 1 e). Another similar lesion was found in the left occ ipital lobe, in addition to multiple punctate similar lesions elsewhere in the brain . Case 2 A 22-year-old man was admitt ed with progressive left hemi- paresis, headache, and somnolence . A diagnosi s of systemic lupus erythematosus had been made 4 years earlier, and he had been tr eated with prednison e, cyclophosphamid e, and mercapt opurine. A diagnosis of pulmonary tuber culosis 2 years before admission led to succ essful tr eatment with str eptomycin, rifamycin, and Myam- butol over a period of 1 year. Physica l examination was normal exc ept for left hemiparesis and hyperreflexia. Laboratory tests were normal. Lupus erythemato sus ce lls we re not found, and cerebro- spinal fluid examination revealed only abnormally elevated protein levels. eT (fig. 2A) showed a 3 cm round lesion involving the basal ga nglia on the right with a ce ntral zone of low density s urrounded by an enc ircling ring of co nt rast enhance ment. There was edema in th e s urrounding white matter. Bi opsy of the lesion demonstr ated only nonspec ific inflammatory changes. The patient died on post- operative day 25 due to respiratory complications. At autopsy, a Single brain lesion was found, measuring 3 x 4 cm, involving the right basal ganglia , thalamus, and internal capsul e (fig. 2B), formed by granulomatous and nec rotic tissues cont aining many encysted microorganisms charac terized as Toxoplasma g ondii. Ca se 3 A 5-year-old boy was admitted with an 8 month hist ory of fever and weig ht loss. On examination, enlar ge ment of the cervica l lymph nodes, li ve r, and spleen were noted. A diagnosis of Hodgkin dis- ease, mixed cellularity, st age IIIB, was made by lymph node bi opsy and laparo tomy, and treatment with MOPP was begun. Fi ve months later he returned with right hemiplegia and bilateral Babinski signs. eT showe d a round lesion 12 mm in diameter in the posterior po rtion of the basal ga ng li a on the ri ght with ringlike co ntrast enhance ment (fig. 3 A) , and several small irregul ar enhancing nod- ules involving the right pa ri etal and bo th occi pital lobes. , Department of Radiology, Hospital Nossa Senhora das Gra<;as and Hospital de Clinicas of the Federal University of Parana, Curitiba, Brazil. Address reprint requests to S. Mazer, Benjamin Constant. 90 / 113, 80.000 Curitiba, Brazil. 2 Department of Neuros urgery, Hospital Nossa Senhora das Gra<;as and Hos pital de Clinicas of the Federal University of Parand, Curitiba, Brazi l. 3 Department of Pediatrics, Hospital Nossa Senhora das Gra<;as and Hospital de Clinicas of th e Federal University of Parana, Curitiba, Brazi l. , Department of Pathology, Hospital Nossa Senhora das Gra<; as and Hos pital de Clinicas of the Federal University of Parana. Curitiba, Brazil. AJNR 4 :458-460, May / June 1983 0195-6 108 / 83 / 0403 -045 8 $00 .00 © Ameri ca n Roent gen Ray Society