case_images: PMC11033401_01
case_images: Preoperative findings: the lesion showed anechoic cysts with no obvious blood flow signal in the cyst wall in the left abdomen on an ultrasonogram (A). Contrast-enhanced abdominal-pelvic CT scanning showed a huge, slightly low-density lesion (blue star) with some septations (white arrow) in the retroperitoneum, which compressed the neighboring organs, pushing the left kidney downward (green arrow), pancreas upward (red arrow), and intestine rightward (orange arrow) (B,C: axial view, D,E: coronal view, F: sagittal view).
case_images: fped-12-1369787-g001.jpg
case_images: PMC11033401_01_fped-12-1369787-g001.jpg
case_images: F1
case_images: The abdominal ultrasound indicated a large hypoechoic mass characterized by a thick wall, septations dividing cystic spaces, absence of mural nodules, and no blood flow signals on color Doppler flow imaging (Figure 1A). Intravenous contrast-enhanced abdominal-pelvic computed tomography (CT) imaging revealed a retroperitoneal cystic lesion measuring 135 mm x 117 mm x 186 mm (Figures 1C,D,F) without invading adjacent structures but displacing the left kidney downward (Figure 1E), pancreas upward (Figure 1D), and intestine rightward (Figures 1B,C). The capsule and septa showed slight enhancement, while the cystic components lacked enhancement (Figures 1B,C).
case_images: Intraoperative findings: (A) huge cystic lesion (blue star). (B,C) Retroperitoneal lesion located in the left anterior pararenal space. (D,E) Lesion adhered to the left renal vein, left renal artery, inferior vena cava, and aorta ventralis. (F) Lesion was removed completely.
case_images: fped-12-1369787-g002.jpg
case_images: PMC11033401_01_fped-12-1369787-g002.jpg
case_images: F2
case_images: During laparoscopic observation, a large thick-walled retroperitoneal cyst was identified (Figure 2A), extending toward the spleen, adrenal gland, cauda pancreatis, and down to the left ovarian appendage. Notably, significant adhesions were observed between the lesion in the left anterior pararenal space (Figures 2B,C) and the aorta ventralis (Figure 2E), inferior vena cava (Figure 2E), and left renal pedicle (Figure 2D). Consequently, complete resection with cystectomy was performed (Figure 2F).
case_images: Postoperative pathology: (A) glial tissue (H&E, x200). (B) Nerve bundle tissue (H&E, x200). (C) Ganglia tissue (H&E, x200). (D) Glial tissue was strongly positive for GFAP (IHC, x200). (E) Glial tissue and nerve bundles were positive for S100 (IHC, x200). (F) Glial tissue was weakly positive for NSE (IHC, x200).
case_images: fped-12-1369787-g003.jpg
case_images: PMC11033401_01_fped-12-1369787-g003.jpg
case_images: F3
case_images: Histologically, the cyst wall consisted of fibrous connective tissue, mature central neuroepithelium (Figure 3A), nerve bundles (Figure 3B), and ganglia (Figure 3C). Immunohistochemistry (IHC) confirmed strong positive expression of glial tissue using glial fibrillary acidic protein (GFAP) (Figure 3D). S100 also exhibited positivity in both the glial tissue and nerve bundles (Figure 3E). NSE was observed in the glial tissue, while positive expression was seen in the nerve bundles and ganglia (Figure 3F). No other embryonic derivatives or indications of malignancy were detected.