title: Thyroid cancer presenting as a PET incidentaloma in a patient with concomitant breast cancer metastases to the thyroid.
abstract: BACKGROUND
  Metastases to the thyroid gland are considered a rare cause of thyroid tumor. Furthermore, a relationship between breast and thyroid carcinoma has been previously proposed.
  
  
  METHODS
  We describe the case of a 59-year-old woman who presented with simultaneous papillary and breast carcinoma within the thyroid gland. F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) done for the evaluation of her metastatic breast cancer revealed a thyroid incidentaloma with a high metabolic rate (standardized uptake value [SUV] of 13). She underwent thyroidectomy and the pathology revealed papillary thyroid carcinoma corresponding to the lesion visualized on FDG PET. However, small metastatic implants of breast carcinoma were seen within the opposite thyroid lobe.
  
  
  CONCLUSIONS
  This is a rare description of a concomitant papillary thyroid carcinoma presenting as an FDG PET incidentaloma alongside breast cancer metastases to the thyroid gland. Thyroid and breast cancer sometimes occur in the same patient. However, no explanation has been found to link these 2 cancers. Although uncommon, FDG PET thyroid incidentalomas seem to harbor a higher rate of malignancy than incidentalomas found on conventional imaging. In the appropriate clinical setting, it is therefore suggested to investigate these lesions thoroughly.
authors.affiliation: Division of Endocrinology, Department of Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada.
authors.forename: Rébecca
authors.initials: R
authors.lastname: Leboeuf
authors.forename: François
authors.initials: F
authors.lastname: Bénard
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Langlois
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000556:secondary; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000532:radiotherapy / Q000556:secondary* / Q000601:surgery; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy; D018450:Disease Progression; D004967:Estrogens; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D033162:Incidental Findings; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008175:Lung Neoplasms / Q000188:drug therapy / Q000556:secondary; D015412:Mastectomy, Segmental; D008479:Mediastinal Neoplasms / Q000188:drug therapy / Q000556:secondary; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis; D009376:Neoplasms, Hormone-Dependent / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000532:radiotherapy / Q000556:secondary* / Q000601:surgery; D009381:Neoplasms, Radiation-Induced / Q000000981:diagnostic imaging / Q000209:etiology; D016609:Neoplasms, Second Primary / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000627:therapeutic use; D018714:Radiotherapy, Adjuvant; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D013629:Tamoxifen / Q000627:therapeutic use; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000532:radiotherapy / Q000556:secondary*; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
chemical_list: D018931:Antineoplastic Agents, Hormonal; D004967:Estrogens; D007457:Iodine Radioisotopes; D009363:Neoplasm Proteins; D019275:Radiopharmaceuticals; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D013629:Tamoxifen; D019788:Fluorodeoxyglucose F18