title: False positive localisation of C-11 methionine in a colloid nodule.
abstract: A 45-year-old female diagnosed with carcinoma of the left breast on histopathological examination underwent both (18)F-flourodeoxyglucose (FDG) and 11C-methionine (MET) positron emission tomography/computed tomography (PET/CT) as part of a protocol comparing the utility of these tracers for predicting a response to neoadjuvant chemotherapy in breast carcinoma. Abnormal FDG and MET accumulation was noted in the left breast primary, left axillary lymph nodes, and also in a well-defined nodule present in the left lobe of the thyroid gland. Keeping in mind the possibility of thyroid neoplasm/metastasis, the patient was referred for fine needle aspiration cytology (FNAC) from the thyroid nodule that revealed features of a simple colloid nodule. Focal thyroid lesions incidentally found on (18)F-FDG PET/CT have a high risk of thyroid malignancy. Non-specific accumulation of FDG in thyroid adenomas is also known. This case highlights a potential cause for false positive on C-11 MET PET/CT in colloid adenomas, which should be kept in mind while using this tracer for oncological indications.
authors.affiliation: Division of PET Imaging, Molecular Imaging and Research Centre, New Delhi, India.
authors.forename: Sonia
authors.initials: S
authors.lastname: Mahajan
authors.forename: Madhavi
authors.initials: M
authors.lastname: Tripathi
authors.forename: Abhinav
authors.initials: A
authors.lastname: Jaimini
authors.forename: Anant
authors.initials: A
authors.lastname: Dinesh
keywords: Breast carcinoma; C-11 MET; F-18 flourodeoxyglucose; colloid adenoma
references.citation: J Clin Endocrinol Metab. 2002 Apr;87(4):1517-20
references.pmid: 11932274
references.citation: Br J Cancer. 1991 Dec;64(6):1121-4
references.pmid: 1662533
references.citation: Surgery. 2001 Dec;130(6):941-6
references.pmid: 11742321
references.citation: Eur J Nucl Med. 1999 Oct;26(10):1363-78
references.pmid: 10541839
references.citation: J Clin Endocrinol Metab. 2003 Sep;88(9):4100-4
references.pmid: 12970270
references.citation: Am Surg. 2006 Mar;72(3):272-5
references.pmid: 16553132
references.citation: Thyroid. 1997 Jun;7(3):363-7
references.pmid: 9226204
references.citation: Exp Clin Endocrinol Diabetes. 2000;108(3):191-6
references.pmid: 10926315
references.citation: J Clin Endocrinol Metab. 1999 Sep;84(9):3228-34
references.pmid: 10487692
references.citation: Clin Nucl Med. 2001 Mar;26(3):193-7
references.pmid: 11245108
references.citation: J Nucl Med. 1993 Nov;34(11):1886-91
references.pmid: 8229229
references.citation: Laryngoscope. 2005 Jun;115(6):1074-8
references.pmid: 15933524
references.citation: J Nucl Med. 1995 Mar;36(3):484-92
references.pmid: 7884515