PMC8091625_01
A technetium-99 m (99mTc)-labeled red blood cell (RBC) scintigraphy. A) Imaging during the first 30 minutes of injecting 99mTc-labeled RBCs shows a focal site of active gastrointestinal bleeding near the epigastric and left hypochondriac region (red arrow). B) Delayed imaging performed 18 hours after 99mTc-labeled RBCs injection shows tagged RBCs in the transverse colon (green arrow).
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However, delayed imaging (performed 18 hours later) showed tagged RBCs in the transverse colon, suggesting transit of tracer through the GI tract (Figure 1).
An irregular growth with oozing blood in the transverse colon as seen on colonoscopy.
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An irregular growth measuring 2.0 x 2.0 cm2 with oozing blood was identified in the transverse colon, approximately 8.0 cm proximal (considering anal verge as the reference point) to the ileocolic anastomosis site (Figure 2).
Histopathological appearance of colonoscopic biopsies taken from the growth in the transverse colon on hematoxylin and eosin staining under the light microscope. A) Tubular gland formation consistent with the tubular adenoma (white arrow) (40 x magnification). B) Areas of high-grade dysplasia (asterisk) with hyperchromasia, loss of nuclear polarity, and nuclear stratification (200 x magnification).
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Histopathology showed features of tubular adenoma with focal areas of high-grade dysplasia (Figure 3).
Histopathological appearance of 2.0 x 2.0 x 2.0 cm3 polypoid, moderately differentiated adenocarcinoma taken out from the surgically resected transverse colon on hematoxylin and eosin staining under the light microscope (40 x  magnification). A) Tumor cells invading the muscularis propria (white arrow). B) Adenomatous features showing multiple tubular glands suggestive of tumor arising in the background of a tubular adenoma.
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The histopathology of the 2.0 x 2.0 x 2.0 cm3 polypoid tumor confirmed the diagnosis of moderately differentiated adenocarcinoma arising in the background of an adenoma (Figure 4).