Cold Splenic Lesion on Tc-99m Colloid and Denatured RBC Scintigraphy

A 35-year-old man presented with a history of G6PD deficiency and thalassemia intermedia. Ultrasound, CT, and magnetic resonance imaging were done because of splenomegaly, which showed a 7-cm splenic mass of indeterminate nature. Tc-99m tin colloid liver–spleen and denatured RBC scans were performed. The mass showed photopenia in both scans. Ultrasound-guided biopsy confirmed a diagnosis of extramedullary splenic hematopoiesis. In contrast to other reported cases, this case was unusual in that a focal “cold” splenic defect was noted in extramedullary hematopoietic tissue. Extramedullary hematopoiesis should be included in the differential diagnoses of a cold splenic defect on colloid and denatured red cell scans.