PMC9800427_01
Imaging at the time of the first visit.. (a) Ultrasonography showed an accessory spleen caudal to the spleen, appearing as a round mass approximately 26 mm in diameter (arrows). (b) The accessory spleen with no blood flow signal (arrows). (c) Contrast-enhanced computed tomography scan showed that the accessory spleen had slight dark staining at the margins, but other areas were poorly contrasted and showed evidence of accessory splenic infarction (arrows). (d) The accessory spleen showed a whirlpool sign with a continuous vascular structure from the splenic hilum (arrowhead). (e) Gadolinium magnetic resonance imaging showed no contrast effect in the accessory spleen. (f) Gadolinium magnetic resonance imaging showed low signal on T2-weighted imaging, indicating hemorrhagic necrosis.
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There was also an increase in the fatty tissue hyperechoic region around the accessory spleen area, suggesting inflammation (Fig. 1a, b). The accessory spleen vascular structure was associated with the splenic hilum, showing a whirlpool sign (Fig. 1c, d). T2-weighted imaging (T2WI) with no contrast effect in the accessory spleen, indicating hemorrhagic necrosis (Fig. 1e, f). This patient was diagnosed as having accessory spleen torsion.
Ultrasound follow-up. (a) The accessory spleen shrunk to 24.6 mm (94 %) and blood flow signals ceased at 16 days after the first visit.. (b) The accessory spleen shrunk to 17.9 mm (96 %) at 32 days after the first visit.. (c) The accessory spleen shrunk to 12.8 mm (49 %) at 60 days after the first visit.
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Sixteen days after admission, the abdominal findings had resolved, blood tests normalized, and the accessory spleen had shrunk (Fig. 2).
Computed tomography (CT) and magnetic resonance imaging (MRI) at 60 days from the first visit.. (a, b) Gadolinium magnetic resonance imaging showed a contrast effect on a part of the accessory spleen and findings of restored blood flow to the accessory spleen (arrows).. (c, d) Computed tomography scans showed that the whirlpool sign (arrowheads), observed two months earlier (e; arrowhead), had disappeared.
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Two months later, Gd-MRI scans showed a contrast effect in a portion of the tortuous accessory spleen and findings of restored blood flow to the accessory spleen (Fig. 3a, b). The whirlpool sign had disappeared from the CT scans, and the torsion had resolved (Fig. 3c, d, e).
(a, b) Arrows: the accessory spleen; arrowhead: the vascular pedicle.. (c) Dotted line: infarction with central necrotic tissue and granulation tissue formation.
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The adhesions were dissected, the vascular pattern was clipped, and the accessory spleen was removed (Fig. 4a, b). The yellowish nodule had a central necrotic tissue area with granulation tissue formation, a finding suggestive of infarction (Fig. 4c).