Quiz page answers April 2005

What do you observe on this computed tomographic image (with contrast) of the brain? What are your differential diagnoses?

This scan of the brain reveals a nonenhancing hypodense lesion occupying the right frontoparietal, internal capsule and basal ganglia region, with surrounding cerebral edema, and a 2-cm contrast-enhancing lesion in the left periventricular region. Differential diagnoses: pyogenic brain abscess, toxoplasmosis, and neoplasm. Histology of brain biopsy showed diffuse large B-cell lymphoma.

The patient then complained of graft tenderness. What do you observe on this computed tomographic image (with contrast) of the graft kidney? What is your final diagnosis?

This scan of the graft kidney shows a 4-cm nonenhancing mass lesion at its inferolateral aspect. Intralesional needle aspirate and biopsy under ultrasound guidance revealed lymphoid cells that expressed B-cell but not T-cell markers. In situ hybridization demonstrated the presence of Epstein-Barr virus-encoded RNA (EBER).