Cover Illustration: Case of the Month—a Small Sigmoid Colon Cancer with Lymph Node Metastasis
A 58-year-old man with a sigmoid colon lesion was referred to our hospital. Colonoscopy revealed a 6 mm polypoid lesion (Cover Illustration A), and barium enema revealed an elevated lesion with shallow central depression (Cover Illustration B). The tangential view showed a slight wall deformity which suggested deep invasion (Figure C).
Tumor macroscopic type was defined by chromo colonoscopy with indigo carmine as IIa + IIc (Figure D). A close-up view showed an irregular pit pattern. Magnifying colonoscopy with crystal violet showed a typical invasive pattern on the surface of the depressed area (Figure E). These results suggested tumor invasion of the deep submucosal layer.
Laparoscopic sigmoidectomy was performed. The tumor size was 6 mm. Histopathologically, the tumor invaded the submucosal layer (4000 µm, “sm2”) and was classified as well differentiated adenocarcinoma, high grade atypia (Figure F). There was lymphatic infiltration but no venous infiltration. Metastasis was found in two of seven dissected lymph nodes, and the histological stage was pT1N1M0, IIIA.
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