Thallium imaging in cardiac lymphoma.

A clinicopathologic correlation was made of thallium-201 myocardial perfusion imaging in two patients with massive myocardial invasion by malignant lymphoma. Despite extensive tumor involvement, the thallium scintigram was normal in one patient, while the other had only a modest-sized region of reduced tracer uptake. The discrepancy between the results of thallium scans and postmortem observations in these patients is probably related to uptake of thallium by tumor cells. The ability of any cellular and well-perfused tissue to absorb potassium, and potassium analogs such as thallium, suggest that thallium-201 scintigraphy may not be a useful method to screen for cardiac involvement in patients with known malignant neoplasms.