Splenic Infarction Mimicking a Necrotizing Metastasis of Malignant Melanoma on F-18 FDG PET/CT

FDG PET/CT Findings in Multiple Splenic Amebomas (Amebic Granulomas)

Splenic ameboma (amebic granuloma) is rare. A 38-year-old man with a severe pneumonia due to inhalation of swimming pool water 18 months ago complained of night sweat, tiredness, and anorexia for 1 month. Abdominal ultrasound showed multiple nodules in the spleen. These nodules showed slight enhancement on enhanced CT and intense FDG uptake on PET/CT. Splenectomy was performed. Multiple splenic amebomas were confirmed by pathology. Free-living amoebae were also detected in samples of pleural effusion and blood. Splenic ameboma, although rare, should be included in the differential diagnosis with isolated focally increased FDG activity in the spleen.

Enhanced CT and FDG PET/CT findings of splenic hamartoma

Splenic hamartomas are very rare benign vascular tumors. A 67-year-old man was referred after an incidental detection of a splenic lesion. Abdominal-enhanced CT showed a splenic lesion with progressive enhancement. This lesion showed intense FDG uptake with an SUVmax of 9.2. The patient underwent splenectomy. Splenic hamartoma was confirmed by pathologic evaluation. In this tumor, the disorganized splenic sinus contained a large amount of lymphocytes and plasma cells, which may contribute to the intense FDG uptake. This case indicates that splenic hamartoma should be included in the differential diagnosis of focal FDG accumulation along with tumor and nontumor conditions.

FDG uptake in splenic epidermoid cyst with hemorrhage

Splenic epidermoid cyst is a rare entity and rarely becomes complicated by hemorrhage. We present a case of splenic epidermoid cyst with old hemorrhage showing strong FDG uptake in the cyst wall. Histopathology revealed granulation tissue with abundant inflammatory cells, including many hemosiderin-laden macrophages, in the inner layer of the cyst wall. The abundant inflammatory cells in the granulation tissue may contribute to the strong FDG uptake of the cyst wall. This case highlights that a benign lesion with hemorrhage should be included in the differential diagnosis of abnormal splenic FDG uptake along with tumor and inflammatory processes.