A Case of Metastasis from Rectal Carcinoma to the Thyroid Gland in which FDG-PET was Useful in Diagnosis

Tomonori Miyazawa¹⁾²⁾, Haruhiko Makino²⁾, Hiroshi Tomita²⁾, and Katsuyoshi Hatakeyama¹⁾

Division of Digestive and General Surgery, Niigata Graduate School of Medical and Dental Science¹⁾
Department of Surgery, Niigata Prefectural Sakamachi Hospital²⁾

We report a case of metastasis from rectal carcinoma to the thyroid gland in which fluorodeoxyglucose-positron emission tomography was useful in diagnosis. A 60-year-old woman who had undergone abdominoperineal resection of the rectum for rectal cancer in September 2001 was subsequently found to have lung metastasis necessitating wedge resection of the left lung in January 2002. She then underwent 7 courses of l-LV/5FU chemotherapy, but CEA gradually increased. We examined the patient for metastasis using systemic computed tomography and scintigraphy, but found no definite metastatic focus or local recurrence. In December 2003, FDG-PET indicated FDG accumulation in the left neck and the patient was diagnosed with metastasis to the thyroid gland from rectal carcinoma, undergoing left hemithyroidectomy in January 2004. Pathological finding showed adenocarcinoma metastasis to the thyroid gland-a very rare metastasis, with 5 cases, including ours reported in Japan. We found FDG-PET useful for detecting metastasis in patients with rectal cancer whose tumor markers increased after surgery despite normal results from conventional examination modalities.

Key words
rectal carcinoma, metastasis to the thyroid gland, FDG-PET

Reprint requests
Tomonori Miyazawa Division of Digestive and General Surgery, Niigata Graduate School of Medical and Dental Science
1-757 Asahimachidori, Niigata, 951-8510 JAPAN

Accepted
February 22, 2006

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