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An official publication of the Middle-Eastern Association for Cancer Research
Clinical Cancer Investigation Journal
ISSN Print: 2278-1668, Online: 2278-0513
Year: 2015   |   Volume: 4   |   Issue: 2   |   Page: 289-290     View issue
Metachronous second primary of sigmoid colon presenting as an atypical extraluminal pedunculated polypoidal fluorodeoxyglucose-positron emission tomography-computed tomography incidentaloma
Sandip Basu, Abhishek Mahajan


In this communication, an atypical extraluminal fluorodeoxyglucose (FDG)-positron emission tomography-computed tomography (PET/CT) incidentaloma in the gut is illustrated in a patient of breast carcinoma, with emphasis on the importance of careful radiopathological correlation. A 50-year-old female, diagnosed patient of infiltrating ductal carcinoma grade II, had undergone left modified radical mastectomy, followed by 6 cycles of chemotherapy 4 years previously and was referred for FDG-PET/CT for whole body disease survey. A noncontrast low-dose FDG-PET/CT [Figure 1] demonstrated intense rounded focus of FDG activity just postero-superior to the urinary bladder that was adherent to bowel the wall, but was primarily extraluminal and abutted the uterus. The transverse pelvic ultrasonography of the abdomen demonstrated a well-defined round hypoechoic extraluminal lesion measuring 3.3 cm × 3.1 cm in close proximity to sigmoid loop. A correlative magnetic resonance imaging [Figure 2] demonstrated a heterogeneous hyperintense lesion (arrow) on axial T2-weighted images [Figure 2]a and sagittal T2-weighted images [Figure 2]b. The lesion was hypointense on precontrast T1-weighted images and demonstrated enhancement on postcontrast T1 weighted images and close to the sigmoid colon (X) with distinct plane between the two. The diagnosis was inconclusive, and a sigmoidoscopic biopsy correlation was called for. A sigmoidoscopy and biopsy revealed a moderately differentiated adenocarcinoma. During the surgery, a pedunculated polypoidal lesion measuring 3 cm × 2.1 cm × 2 cm was detected. The final histopathology report was moderately differentiated adenocarcinoma with a villous configuration. Extensive invasion of stalk of the tumor was noted going beyond muscularis mucosa.

Fluorodeoxyglucose-positron emission tomography-computed tomography incidentaloma indicating an unsuspected malignancy has been reported in multiple reports in different organ systems such as thyroid, parotid, breast, and so on. [1],[2],[3] The importance of the biopsy correlation of FDG-PET/CT incidentaloma in the gastrointestinal tract (even if they are atypical) cannot be overemphasized. This is particularly important for gut incidentaloma, which would warrant for an endoscopic biopsy correlation. The diagnostic challenge in the present case was related primarily to the extraluminal pedunculated nature of the mass. Frequently, as observed in this patient, this could detect unknown primary at its early stage and thereby could result in a favorable outcome if managed appropriately.{Figure 1}{Figure 2}


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Online since 01 December, 2011
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ISSN Print: 2278-1668, Online: 2278-0513