Silk suture granuloma with false-positive findings on PET/CT accompanied by peritoneal metastasis after colon cancer surgery.
BACKGROUND
Suture granuloma is a rare benign tumor caused by suture material, which usually appears several months or years after surgery.


METHODS
A 71-year-old man underwent sigmoidectomy and partial hepatectomy (S6) for sigmoid colon cancer and synchronous liver metastasis at a previous hospital. At 4 postoperative months, surveillance computed tomography (CT) revealed a suspicious tumor at the hepatic resection stump. He was referred to our hospital for further examinations and treatments. Positron emission tomography/CT (PET/CT) revealed abnormal hepatic F-18 fluorodeoxyglucose (FDG) uptake below the diaphragm at the S5/S8 surface. Peritoneal metastasis was suspected and surgery was performed. White nodules were found in the Douglas pouch. A diagnosis of adenocarcinoma was confirmed by frozen section analysis of the nodules. He underwent a partial hepatectomy (S5/S8) and partial resection of the diaphragm. Pathological examination showed that the liver tumor was a foreign body granuloma that included silk suture material.


CONCLUSIONS
Although postoperative PET/CT surveillance is useful following malignant tumor resection, it is important to note that PET/CT false-positive findings are possible. Furthermore, PET/CT cannot detect small peritoneal metastases, necessitating a thorough abdominal examination.


CONCLUSIONS
In cases of malignancy, the possibility of postoperative suture granuloma should be considered. In addition, a thorough surgical examination of the abdomen should be performed in cases of suspected recurrence.
Department of Surgery, Ibaraki Prefectural Central Hospital, 6528 Koibuchi, Kasama-shi, Ibaraki 309-1793, Japan. Electronic address: somatsuura-tky@umin.ac.jp.
Sohei
S
Matsuura
Department of Surgery, Ibaraki Prefectural Central Hospital, 6528 Koibuchi, Kasama-shi, Ibaraki 309-1793, Japan. Electronic address: sasakik-tky@umin.ac.jp.
Kazuhito
K
Sasaki
Department of Surgery, Ibaraki Prefectural Central Hospital, 6528 Koibuchi, Kasama-shi, Ibaraki 309-1793, Japan. Electronic address: hi-kawasaki@chubyoin.pref.ibaraki.jp.
Hiroshi
H
Kawasaki
Department of Surgery, Ibaraki Prefectural Central Hospital, 6528 Koibuchi, Kasama-shi, Ibaraki 309-1793, Japan. Electronic address: h-abe@chubyoin.pref.ibaraki.jp.
Hideki
H
Abe
Department of Surgery, Ibaraki Prefectural Central Hospital, 6528 Koibuchi, Kasama-shi, Ibaraki 309-1793, Japan. Electronic address: h-nagai@chubyoin.pref.ibaraki.jp.
Hideo
H
Nagai
Department of Surgery, Ibaraki Prefectural Central Hospital, 6528 Koibuchi, Kasama-shi, Ibaraki 309-1793, Japan. Electronic address: f-yoshimi@chubyoin.pref.ibaraki.jp.
Fuyo
F
Yoshimi
Colorectal cancer; Foreign body granuloma; Peritoneal metastasis; Positron emission tomography; Suture granuloma
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