This 60 y/o female presented with right upper quadrant pain. An ultrasound exam (not shown) was initially performed. Findings on this exam led to an abdominal CT. Selected post contrast images are shown above. Surgical excision of the lesion was performed. There was invasion of the adjacent rib and musculature by a focal tumor mass. Immunohistochemical studies and consultation with the Armed Forces Institute of Pathology (AFIP) led to the diagnosis of a focally invasive malignant mesothelioma.