case_images: PMC8437670_01
case_images: Patient's initial presentation of left lower extremity edema.
case_images: CRIM2021-3526071.001.jpg
case_images: PMC8437670_01_CRIM2021-3526071.001.jpg
case_images: fig1
case_images: On physical examination, the presence of pitting edema of her left lower extremity was noted (Figure 1).
case_images: Computed tomography of the abdomen reveals 8.7 x 6.9 x 8.5 cm mass (red arrow) in the retroperitoneal space.
case_images: CRIM2021-3526071.002.jpg
case_images: PMC8437670_01_CRIM2021-3526071.002.jpg
case_images: fig2
case_images: A computed tomography (CT) angiography of the abdomen/pelvis was then performed and revealed a large heterogeneous left pelvic retroperitoneal mass centered at the left iliac chain region spanning 8.7 x 6.9 x 8.5 cm with probable compression/occlusion of the adjacent iliac vein (Figure 2).
case_images: (a) Nest of tumor cells showing areas of necrosis (H&E, original magnification x100). (b) Immunohistochemical stain positive for SOX10 (H&E, original magnification x100). (c) Immunohistochemical stain positive for S100 (H&E, original magnification x100).
case_images: CRIM2021-3526071.003.jpg
case_images: PMC8437670_01_CRIM2021-3526071.003.jpg
case_images: fig3
case_images: A CT-guided abdominal mass needle core biopsy was performed, and the sample was sent for H&E staining (Figure 3(a)) as well as immunohistochemical (IHC) staining. Immunostaining showed that the tumor cells were diffusely and strongly positive for SOX10 (Figure 3(b)) but were negative for CK7, CK20, GATA3, and PAX8. The tumor cells were also positive for S100 immunostaining (Figure 3(c)) and BRAF V600E mutation, thereby further confirming the diagnosis.