title: Isolated skeletal muscle metastatic deposit in a patient with micropapillary carcinoma thyroid identified by 18F FDG PET CT.
abstract: Micropapillary carcinoma of thyroid is said to be low risk differentiated thyroid malignancy with excellent prognosis. We report the identification of an isolated FDG avid muscle deposit in a treated case of micropapillary carcinoma of the right lobe and widely invasive follicular carcinoma of the left lobe thyroid gland. Patient was found to have an elevated thyroglobulin level with negative iodine scan (TENIS syndrome) on follow up at 6 months. An 18F FDG PET CT (18 fluorine-fluorodeoxyglucose positron emission computed tomography) whole body study revealed a solitary FDG avid deltoid muscle deposit which was histopathologically confirmed to be metastatic papillary carcinoma. While follicular carcinoma is known to have distant metastases, this may be the first reported case of solitary skeletal metastases from micropapillary carcinoma of thyroid and probably the second reported skeletal muscle deposit from DTC detected on 18F FDG PET CT done following elevated thyroglobulin level and negative 131 iodine WB scan (TENIS). This case also assumes importance because it demonstrates possibility of metastases even from a micropapillary carcinoma in contrast to American Thyroid Association guidelines (2009) which suggests that micropapillary carcinoma of thyroid does not merit further treatment after a Total Thyroidectomy.
authors.affiliation: Deptt. of Nuclear Medicine & PET CT, Amrita Institute of Medical Sciences (Amrita Vishwa Vidyapeetham), Cochin, Kerala 682041, India. Electronic address: drmanjitsarma@gmail.com.
authors.forename: Manjit
authors.initials: M
authors.lastname: Sarma
authors.affiliation: Deptt. of Nuclear Medicine & PET CT, Amrita Institute of Medical Sciences (Amrita Vishwa Vidyapeetham), Cochin, Kerala 682041, India. Electronic address: sonik.bhavya@gmail.com.
authors.forename: Bhavya
authors.initials: B
authors.lastname: Sonik
authors.affiliation: Deptt. of Nuclear Medicine & PET CT, Amrita Institute of Medical Sciences (Amrita Vishwa Vidyapeetham), Cochin, Kerala 682041, India. Electronic address: padmas@aims.amrita.edu.
authors.forename: Padma
authors.initials: P
authors.lastname: Subramanyam
authors.affiliation: Deptt. of Nuclear Medicine & PET CT, Amrita Institute of Medical Sciences (Amrita Vishwa Vidyapeetham), Cochin, Kerala 682041, India. Electronic address: drpssundaram@gmail.com.
authors.forename: Palaniswamy Shanmuga
authors.initials: PS
authors.lastname: Sundaram
mesh_terms: D000368:Aged; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging* / Q000556:secondary; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D019042:Muscle Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000473:pathology; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: Dedifferentiated thyroid carcinoma; Micropapillary carcinoma thyroid; Solitary muscle metastasis; TENIS