title: Fine-needle thyroid aspiration-induced hemorrhage of an unsuspected parathyroid adenoma misdiagnosed as a thyroid nodule: remission and relapse of hyperparathyroidism.
abstract: BACKGROUND
  Temporary remission of primary hyperparathyroidism (PHPT) following fine-needle aspiration (FNA)-induced hemorrhage of a parathyroid adenoma is extremely rare. The purpose of this report was to illustrate that parathyroid adenomas can masquerade as thyroid nodules and that these patients must be monitored closely following remission as their hyperparathyroidism may recur.
  
  
  METHODS
  This report describes a patient who presented with a neck mass and was incidentally found to have PHPT. Ultrasound (US) evaluation revealed a lesion that was diagnosed as a thyroid nodule. After a nondiagnostic FNA, she developed a large neck hematoma and her PHPT went into remission. Soon thereafter, her hyperparathyroidism recurred, and she underwent parathyroidectomy and thyroid lobectomy, which confirmed a large parathyroid adenoma.
  
  
  CONCLUSIONS
  This report illustrates that remission of PHPT can occur because of FNA-induced hemorrhage leading to autoinfarction of a parathyroid adenoma. Following autoinfarction, the patient's parathyroid hormone and calcium levels must be monitored closely as the remission of PHPT may be temporary. Further, although US is a fast, inexpensive, often reliable modality for diagnosing neck masses, it does not always accurately identify parathyroid adenomas.
  
  
  CONCLUSIONS
  Clinicians must be cognizant of the possibility that parathyroid adenomas can masquerade as thyroid nodules on US, especially as most patients with parathyroid adenomas are asymptomatic at presentation.
authors: Department of Otolaryngology/Head and Neck Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15213, USA. hootonjm@upmc.edu
authors: Jessica H
authors: JH
authors: Maxwell
authors: Louise
authors: L
authors: Giroux
authors: Julie
authors: J
authors: Bunner
authors: Umamaheswar
authors: U
authors: Duvvuri