Fine-needle thyroid aspiration-induced hemorrhage of an unsuspected parathyroid adenoma misdiagnosed as a thyroid nodule: remission and relapse of hyperparathyroidism.

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.

PATIENT FINDINGS: 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.

SUMMARY: 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.

CONCLUSION: 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.