PMC8141978_01
Unenhanced CT scan revealed a large retroperitoneal cystic mass. Both ureters were compressed by the homogeneous tumor with consecutive obstructive uropathy.. Images in axial (a) and coronary (b) axis.
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An unenhanced CT scan demonstrated a large, cystic homogeneous tumor with compression of both ureters and consecutive obstructive uropathy (Figure 1).
Preoperative retrograde ureteropyelography revealing lateralization and compression of both ureters as reason of acute renal failure. The examination showed the space-consuming character of the cyst and clarified its impact with consecutive obstructive hydronephrosis grade 3 on both sides. There was no connection between the upper urinary tract and the giant cyst. Ureteral stents were placed on both sides due to acute renal failure during the intervention.. Shown is the upper urinary tract on the right (a, c) and left (b, d) side.
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Communication between the ureters and the tumor was excluded and ureter stents were placed on both sides (Figure 2).
Contrast agent enhanced abdominal CT scan. The retroperitoneal cyst is large (19 cm x 17 cm x 14 cm), non-septated and walled irregularly. While the liquid content is homogeneous (10-15 HU, number sign), the wall appears suspiciously enhanced (60-70 HU, asterisk). The cyst is in close contact with the spinal column (sacral vertebra, S1).. Arrows indicate the ureteral stents. CT scan is enhanced by oral, rectal and intravenous applicated contrast agent (iodine based). Images in coronary (a), axial (b) and sagittal (c) axis.
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An enhanced CT showed the consistently sized (19 cm x 17 cm x 14 cm), non-septated, homogeneous (10-15 HU), suspiciously thick-walled retroperitoneal cyst with a close relationship to both ureters, the sacral vertebra S1 and the duodenum (Figure 3).
Pathological examination demonstrating characteristics of lymphangioma and IgG4+ fibrosis. The wide and slit-like cystic lumen is lined by flat endothelial cells (a, see inlay, arrow). In immunohistochemistry, these cells were D2-40 positive (b). Note the spotted lymphoplasmacellular infiltrates in proximity to the cystic lumina (a, asterisk). Retroperitoneal fibrosis involves the adipose tissue with numerous plasma cells (c). The proportion of IgG4+ plasma cells was extremely high (>50 IgG4+ plasma cells/high power field) in hotspot regions (d).. Length of lower image border: 2.33 mm (a, b) or 0.23 mm c, d).
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These cells expressed podoplanin (positive reaction with antibody clone D2-40, Figure 4) and consequently led to the diagnosis of a lymphangioma.
Follow-up MRI revealed a small cystic residuum and no signs of spacious retroperitoneal fibrosis. Close to the left A. iliaca communis a small fluid structure was detected (a). The wall was enhanced by contrast agent (b, arrow). The presumed residual lymphangioma extended up to the left M. psoas. The ureter wall was enhanced by contrast agent (right > left; arrow head, c, d); however, no relevant uropathy was observed. In addition, no spacious fibrosis was detected in the retroperitoneum.. Sequence protocol: T2 weighted, turbo spin echo, fat saturated (a); T1 weighted, turbo spin echo, fat saturated, gadolinium enhanced (b-d).
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An abdominal MRI showed a small Gadolinium-enhancing lesion with residual fluid in the area of the previous R2 resection (Figure 5).