case_images: PMC11253908_01
case_images: Left submandibular swelling, 4 x 3 cm in size, ill-defined, tender, firm in consistency with restricted mobility.
case_images: autopsy-14-e2024499-g01.jpg
case_images: PMC11253908_01_autopsy-14-e2024499-g01.jpg
case_images: gf01
case_images: On examination, the submandibular swelling was a 4 x 3 cm size single lesion, tender, firm in consistency with restricted mobility, and the overlying skin was unremarkable as shown in Figure 1.
case_images: Photomicrographs of the FNAC. A - Hypercellular cytological smears showing malignant cells dispersed singly as well as in small loosely cohesive clusters with the formation of occasional rosette-like structures (May Grunwald-Giemsa (MGG) stain x100); B - Malignant cells present in a characteristic tigroid background, (MGG stain x400); C - Two cell populations can be appreciated with small round blue cells having high nuclear to cytoplasmic ratio interspersed with large pale cells with abundant finely vacuolated cytoplasm, (MGG stain x400); D - Small round blue cells with dense nuclei with slightly irregular nuclear membranes, coarse chromatin, and inconspicuous nucleoli. Larger cells have fine granular chromatin with 1-2 small nucleoli, (Papanicolaou stain x400).
case_images: autopsy-14-e2024499-g02.jpg
case_images: PMC11253908_01_autopsy-14-e2024499-g02.jpg
case_images: gf02
case_images: Occasional rosette-like structures without a fibrillar center were present, shown in Figures 2A and 2B. Figures 2C and 2D. Frequent atypical mitoses were identified as well.
case_images: Photomicrographs of the cellblock slices. A - Cell block preparation showing malignant cells with similar morphology as seen on smear (H&E x400); B - Tumor cells showing strong nuclear positivity for NKX2.2 (x400); C - Tumor cells showing strong and diffuse membranous positivity for CD 99, (x400); D - Tumor cells showing around 40% Ki-67 proliferation index, (x400); E - Periodic acid-Schiff (PAS) special stain highlighting glycogen present in the larger pale cells with abundant cytoplasm and fine vacuoles, (PAS x400); F - Fluorescence in-situ hybridization (FISH) performed using break-apart probe for EWSR1 gene, showing split green and red signals in the cells, indicating EWSR1 gene rearrangement.
case_images: autopsy-14-e2024499-g03.jpg
case_images: PMC11253908_01_autopsy-14-e2024499-g03.jpg
case_images: gf03
case_images: On IHC, the tumor cells showed strong nuclear positivity for NKX2.2, as shown in Figure 3B, a highly sensitive and specific marker for ES, and strong diffuse membranous positivity for CD 99, as shown in Figure 3C. Ki-67 proliferation index was around 40%, as shown in Figure 3D. Periodic acid-Schiff (PAS) special staining was performed, highlighting the cytoplasmic glycogen in the larger cells with abundant pale cytoplasm with fine vacuoles, as shown in Figure 3E. Additionally, a confirmatory molecular cytogenetic study of fluorescence in-situ hybridization (FISH) was performed on the section from cell block preparation using a break-apart probe for the EWSR1 gene, which revealed split green and red signals in the cells, indicating EWSR1 gene rearrangement as shown in Figure 3F.