case_images: PMC3999573_01
case_images: Inspection reveals an ulcerated tumor in the left lower gingiva.
case_images: cro-0007-0246-g01.jpg
case_images: PMC3999573_01_cro-0007-0246-g01.jpg
case_images: F1
case_images: On clinical examination, an ulcerative, circumferential tumor that arose in the left lower gingiva was visible (fig. 1).
case_images: Immunohistochemical examinations for adenocarcinoma are positive for CK20 (a) and CDX-2 (b), but negative for CK7 (c) and TTF-1 (d).
case_images: cro-0007-0246-g02.jpg
case_images: PMC3999573_01_cro-0007-0246-g02.jpg
case_images: F2
case_images: On the fifth day after the referral, the results of the immunohistochemical staining for adenocarcinoma turned out to be positive for CK20 and caudal-related homeobox transcription factor (CDX-2), and negative for CK7 and thyroid transcription factor-1 (TTF-1) (fig. 2).
case_images: a PET/CT with sagittal reconstruction reveals a large amount of FDG uptake behind the bladder. b Colonoscopy demonstrates a circular ulcerative tumor in the upper rectum.
case_images: cro-0007-0246-g03.jpg
case_images: PMC3999573_01_cro-0007-0246-g03.jpg
case_images: F3
case_images: Moreover, PET-CT showed an accumulation of 18F-fluorodeoxyglucose (FDG) with an SUVmax of 19.0 in the upper rectum (fig. 3a). Based on these additional findings, the patient was persuaded to undergo a colonoscopic examination, which then revealed advanced rectal cancer (fig. 3b).