Splenic defect on 99mTc-sulfur colloid scintigraphy but not on CT in a patient with pancreatic carcinoma.

A 99mTc-sulfur colloid (99mTc-SC) scintigraphic study of a patient with pancreatic carcinoma invading the splenic hilum demonstrated a discrete focal defect of the spleen, while computed tomography (CT) showed a normal spleen. The patient underwent splenectomy and no pathology was found in the spleen. The tumor invasion into the splenic hilum may have caused the defect shown in the 99mTC-SC study, reflecting splenic reticuloendothelial (RE) cell dysfunction, while CT might well represent anatomic structures only. This discrepant finding between functional (99mTc-SC) and anatomic (CT) imaging modalities may be explained by the fact that the impairment of the phagocytic function of the spleen apparently was not severe enough to cause structural changes detected by CT or gross and microscope examination.