ULTRASONOGRAPHIC FEATURES OF ABDOMINAL ECTOPIC SPLENIC TISSUE

Ectopic splenic tissue may be congenital (an accessory spleen) or a re sult of traumatic autotransplantation (splenosis). The purpose of this study was to identify the features of ectopic splenic tissue in ultra sonography (US) scans. Selective spleen scintigraphy (with heat-denatu red erythrocytes labelled with technetium 99m) was performed on 33 pat ients who had undergone splenectomy after trauma; the 25 (76%) for who m the results were positive subsequently underwent US. Of the 25 patie nts, 23 (92%) had one to five foci of ectopic splenic tissue; 62 of th e 68 foci (91%) were in the left upper quadrant. US identified splenic tissue in 17 of the 25 patients (68%). All 44 foci visible with US we re hypoechoic, and 33 of them (75%) exhibited acoustic enhancement or an incomplete hyperechoic rim or both. Nineteen of the foci revealed b y US (43%) were smaller than 1 cm2. No criteria were found to permit d ifferentiation of accessory spleens from splenosis. In three of every four patients who undergo splenectomy after trauma, ectopic splenic ti ssue eventually develops. Radiologists should be aware of this conditi on to avoid incorrectly diagnosing this ectopic tissue as metastasis, adenopathy or another solid tumour. US, in combination with selective spleen scintigraphy, permits a specific diagnosis without invasive pro cedures.