case_images: PMC9845517_01
case_images: Physical examination of the patient's abdomen. Patient's distended abdomen with a protruding mass measuring about 10 cm x 10 cm (A) with superficially visible engorged veins (B)
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case_images: PMC9845517_01_cureus-0015-00000033799-i01.jpg
case_images: FIG1
case_images: The patient's abdomen was distended (Figure 1 A) with a protruding mass measuring about 10 cm x 10 cm with engorged veins visible superficially (Figure 1 B).
case_images: Abdominal CT scan of the patient. Seen is a large intraperitoneal multilobulated mass with a fat component in the anterior of the left kidney
case_images: cureus-0015-00000033799-i02.jpg
case_images: PMC9845517_01_cureus-0015-00000033799-i02.jpg
case_images: FIG2
case_images: Radiologic examination revealed the finding of a large intraperitoneal multilobulated mass with a fat component in the anterior of the left kidney measuring anteroposterior (AP) 11.9 cm   latero-lateral (LL) 11.3   craniocaudal (CC) 12.5 cm that is enlarging to the contralateral side, compressing the left kidney to the posterior, spleen to craniolateral, pancreas and bowel system to the right side (Figure 2).
case_images: Cytopathology photomicrograph from fine needle aspiration biopsy. A: Adipocytes and lipoblasts on low magnification, 40x; B: Mature adipocytes (red arrow) and lipoblasts, both with uni-vacuolated and multi-vacuolated features (black arrow), 100x
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case_images: PMC9845517_01_cureus-0015-00000033799-i03.jpg
case_images: FIG3
case_images: Cytopathology showed mature adipocytes and lipoblasts, both uni-vacuolated and multi-vacuolated lipoblasts (Figure 3).
case_images: Cytopathology photomicrograph examination from the cell block. A: Immature lipid cells known as lipoblast arranged as lobules with a myxoid background (white arrow), H&E, 40x; B: Large lipid cells with clear cytoplasm with their nucleus located at the edge of the cell, H&E, 100x. H&E: Hematoxylin and eosin
case_images: cureus-0015-00000033799-i04.jpg
case_images: PMC9845517_01_cureus-0015-00000033799-i04.jpg
case_images: FIG4
case_images: Cytopathology examination from the cell block (Figure 4) revealed immature lipid cells known as lipoblast that arranged as lobules with a myxoid background.
case_images: Immunohistochemistry (IHC) analysis with anti-S100 antibody. The lipoblast nuclei are strongly positive for anti-S100 antibody staining
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case_images: PMC9845517_01_cureus-0015-00000033799-i05.jpg
case_images: FIG5
case_images: In immunohistochemistry (IHC) analysis (Figure 5), the lipoblast nuclei are strongly positive for anti-S100 antibody staining.
case_images: Resected mass. The mass was soft and measured 16.5 cm x 11.2 cm x 6.5 cm grossly
case_images: cureus-0015-00000033799-i06.jpg
case_images: PMC9845517_01_cureus-0015-00000033799-i06.jpg
case_images: FIG6
case_images: The pediatric surgeon decided to do a laparotomy and radical resection on the suspected benign mass (Figure 6).
case_images: Histopathology examination from the resected mass. A: Lipid tissues arranged in lobules separated by fibrous tissue (white arrow) with a scattered myxoid background. Some fields (black arrow) consist of mature adipocytes, and the other contains lipoblasts (yellow arrow); B: Higher magnification of lipoblasts which shows no presence of malignant cells
case_images: cureus-0015-00000033799-i07.jpg
case_images: PMC9845517_01_cureus-0015-00000033799-i07.jpg
case_images: FIG7
case_images: Microscopically, there were lipid tissues arranged in lobules separated by fibrous tissue with some fields showing myxoid background (Figure 7).