PMC9050271_01
Endoscopic image of the PEComa showing a submucosal polypoid mass with surface ulceration located in the sigmoid colon.
CRIPE2022-7519456.001.jpg
PMC9050271_01_CRIPE2022-7519456.001.jpg
fig1
A colonoscopy revealed a single large bleeding, pedunculated sigmoid polyp measuring 2 cm x 1.5 cm x 1.5 cm (Figure 1).
(a) TFE3 rearranged PECOma: low power. (b, c) High-power image of the polyp showing nested lesional cells (arrows) with clear cytoplasm and round nuclei in mucosa and submucosa of colon. (d, e) Lesional cells showed positive immunoreactivity for HMB-45 and TFE3, while (f) negative reactivity for Melan-A.
CRIPE2022-7519456.002.jpg
PMC9050271_01_CRIPE2022-7519456.002.jpg
fig2
The pathological and microscopic examination of the resected specimen from the sigmoid colon revealed a polypoid mass with a stalk measuring 2.0 x 1.5 x 1.3 cm (Figure 2(a)). Further evaluation showed lesional cells composed of nested pattern with clear to eosinophilic granular cytoplasm, well-defined cell borders, and round nuclei with prominent nucleoli involving the colonic mucosa and submucosa (Figures 2(b) and 2(c)). The immunohistochemical stains showed positive reactivity for HMB-45 (Figure 2(d)) and TFE3 (Figure 2(e)), with negative reactivity for pan-cytokeratin (AE1/AE3), PAX8, synaptophysin, chromogranin, SMA, desmin, CD117, CD68, CD34, and Melan-A (Figure 2(f)).