Large focal defect on liver/spleen scan caused by fatty liver and masquerading as neoplasm

Focal fatty infiltration of the liver may be mistaken for metastatic disease, primary tumor or other space-occupying lesions on CT or ultrasound. Usually, a 99mTc-sulfur colloid scan is sensitive in documenting the presence of Kupffer's cell in such a process. We present a case that was suggestive of focal fatty infiltrate on a CT scan, nondiagnostic on ultrasound, and seen as a large focal defect on the 99mTc-sulfur colloid liver/spleen scan. A 133Xe inhalation study, however, did show uptake in the area of fatty infiltration. A needle biopsy confirmed the diagnosis.