title: Thymoma and parathyroid adenoma: false-positive imaging and intriguing laboratory test results.
abstract: OBJECTIVE
  Parathyroid hormone (PTH)-secreting thymomas are an exceedingly rare entity. A PTH-secreting thymoma was discovered in the workup of a patient with primary hyperparathyroidism. A concomitant parathyroid adenoma was removed from the same patient. We present the intriguing clinical course and review the literature on this rare entity. In addition, we discuss the use of scanning with technetium Tc 99m sestamibi, the PTH assay, and cervical ultrasonography in the workup of a parathyroid adenoma.
  
  
  METHODS
  Scanning with technetium Tc 99m sestamibi demonstrated false-positive uptake of the mediastinal thymoma and false-negative uptake of the true cervical parathyroid adenoma. After removal of the thymoma, the parathyroid adenoma demonstrated appropriate uptake on a follow-up scan. After removal of the parathyroid adenoma, the hyperparathyroidism was cured.
  
  
  CONCLUSIONS
  Given the extremely rare incidence of a PTH-secreting thymoma with a concurrent parathyroid adenoma, we do not recommend alterations in the diagnostic algorithm for primary hyperparathyroidism. However, in this case, the need for 2 separate operations may have been avoided by obtaining an ultrasonogram to further explore the findings on the technetium Tc 99m sestamibi scan. We recommend that both studies be considered in unclear cases of primary hyperparathyroidism.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Wexner Medical Center, The Ohio State University, Columbus.
authors.forename: Lauren C
authors.initials: LC
authors.lastname: Cunningham
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Wexner Medical Center, The Ohio State University, Columbus.
authors.forename: Jun-Ge
authors.initials: JG
authors.lastname: Yu
authors.affiliation: Department of Pathology, Wexner Medical Center, The Ohio State University, Columbus.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Shilo
authors.affiliation: Department of Radiology, Wexner Medical Center, The Ohio State University, Columbus.
authors.forename: Bingfeng
authors.initials: B
authors.lastname: Tang
authors.affiliation: Division of Endocrinology, Department of Internal Medicine, Diabetes, and Metabolism, Wexner Medical Center, The Ohio State University, Columbus.
authors.forename: Lekshmi
authors.initials: L
authors.lastname: Nair
authors.affiliation: Division of Thoracic Surgery, Department of Surgery, Wexner Medical Center, The Ohio State University, Columbus.
authors.forename: Vincent C
authors.initials: VC
authors.lastname: Daniel
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Wexner Medical Center, The Ohio State University, Columbus.
authors.forename: Matthew O
authors.initials: MO
authors.lastname: Old
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging / Q000378:metabolism / Q000601:surgery*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D010281:Parathyroid Hormone / Q000378:metabolism; D010282:Parathyroid Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism / Q000601:surgery*; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi; D013945:Thymoma / Q000000981:diagnostic imaging / Q000378:metabolism / Q000601:surgery*; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D010281:Parathyroid Hormone; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi