PMC8100383_01
Colonoscopy showing a 4 cm firm mass firm with a depressed central aspect.
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fig1
A colonoscopy was performed, and a mass was found in the ascending colon (Figure 1). The tumor was located in the ascending colon, 3 cm to the ileocecal valve, 2.3 cm in size, firm, red-tan, and with central umbilication (Figure 1).
Microphotograph (200x) of the mass showing a very distinctive appearance and consists of different patterns. There were smaller gland or duct-like structures as well as larger nests with cribriform pattern. Some glands or spaces showed mucin-like or basophilic material. The tumor cells were round to oval with fine chromatin, small inconspicuous nucleoli, indistinct cell borders, and light nongranular cytoplasm. Mitotic figures were rare.
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fig2
At higher magnification, the tumor cells showed minimal cytological atypia, scant cytoplasm, fine chromatin, small inconspicuous nucleoli, and rare mitotic figures (Figure 2).
(a) C-kit (100x), (b) CEA (400x), (c) SMA (200x), and (d) P63 (200x), respectively. The luminal epithelial cells of the tumor are positive for C-kit and CEA; the abluminal myoepithelial cells of the tumor are positive for SMA and P63.
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fig3
The luminal epithelial cells were positive for cytokeratin AE1/AE3, C-kit, and CEA, while the abluminal myoepithelial cells were positive for P63 and SMA (Figure 3).