PMC7505754_01
Preoperative examination.. a. Visual inspection revealed flat, elevated lesions and surrounding inflammation on the left side of the anus.. b. Colonoscopy revealed an elevated lesion continuing from the anal skin lesion in the 3 o'clock direction of the anal canal, going toward, but not reaching, the pectinate line.. c. There was not any abnormal accumulation in the anus or rectum through a CT scan and 18F-FDG PET/CT scans.
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The patient was a 70-year-old woman who had developed red and flat elevated lesions, with surrounding inflammation on the left side of the anus that persisted for one year before treatment (Fig. 1a). Colorectal endoscopy confirmed an elevated lesion continuing from the anal skin lesion in the 3 o'clock direction toward, but not reaching, the pectinate line (Fig. 1b). MRI and 18F-FDG PET/CT scans (Fig. 1c). Moreover, there was no metastasis in groin lymph node on preoperative examinations.
The schema showed resection line and lymph node metastasis (*). Photomicrograph of resected specimen showed lymph node metastasis. Blue line transanal resection line, and red line is resection line of ISR.
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On immunohistochemical testing, the samples stained positive for cytokeratin-7 (CK7) and cytokeratin-20 (CK20), but not for gross cystic disease fluid protein-15 (GCDFP15; Fig. 2).
The figures showed HE staining and immunohistochemical staining of the skin biopsy. They revealed that the signal for GCDFP15 was negative, whereas those for CK7 and CK20 were positive (x10, x100).
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Thus, the external anal sphincter was preserved (Fig. 3).