Diagnostic Fine-Needle Aspiration Biopsy of an Intrathyroidal Parathyroid Gland and Subsequent Eucalcemia in a Patient with Primary Hyperparathyroidism

Remission of primary hyperparathyroidism after fine needle aspiration of a parathyroid nodule mistaken for a thyroid nodule

Primary hyperparathyroidism (PHPT) is an endocrine disorder characterized by hypercalcaemia and elevated or inappropriately normal concentrations of parathyroid hormone. Remission of PHPT caused by infarction or hemorrhage of a parathyroid adenoma rarely occurs, either spontaneously or induced, not always leading to a definitive cure. We report a case of 72-year-old women with primary hyperparathyroidism who underwent fine-needle aspiration cytology (FNAC) of a parathyroid adenoma mistaken for a thyroid nodule followed by normalization of parathyroid hormone (PTH) and serum calcium levels. Parathyroid origin was confirmed by immunohistochemistry. PTH levels began to rise at 4 months after FNAC demonstrating recurrence of the PHPT. This report shows that FNAC induced hemorrhage may cause remission of PHPT. Nevertheless, patient´s levels of PTH and serum calcium should be monitored, as remission may only be transitory.

Transient remission of hyperparathyroidism after fine-needle aspiration biopsy

Primary hyperparathyroidism (PHPT) is the unregulated overproduction of parathyroid hormone (PTH), resulting in abnormal calcium homeostasis. PHPT is most commonly caused by a single adenoma of the parathyroid gland, which can have an intrathyroid location in rare cases. The measurement of intact PTH in the washout fluid obtained by ultrasound (US)-guided fineneedle aspiration (FNA) can be useful in clarifying the aetiology of these lesions. This study presented a 48-year-old man with a background history of symptomatic renal stone disease who was diagnosed with PHPT and referred to our Endocrinology department. A neck US revealed a thyroid nodule with a size of 21 mm in the right lobe. The patient underwent US-guided FNA of the lesion. The measurement of PTH in the washout fluid was significantly elevated. Following the procedure, he reported neck pain and noticed distal paraesthesias in the upper limbs. Blood test results showed significant hypocalcaemia and supplementation with calcium and calcitriol was started. The patient was closely monitored. Recurrence of hypercalcaemia was later observed, and the patient was submitted to surgery. We present a case of FNAinduced transitory remission of PHPT in a patient with an intrathyroid parathyroid adenoma. We conjecture that intra-nodular haemorrhage might have occurred, which temporarily affected the viability of the autonomous parathyroid tissue. A few similar cases of spontaneous or induced remission of PHPT after FNA have been previously described in the literature. This remission can be transitory or permanent, depending on the degree of cellular damage thus follow-up of these patients is recommended.

Remission of Primary Hyperparathyroidism Following Fine-Needle Aspiration Biopsy: A Case Report and Review of the Literature

Background

Spontaneous or fine-needle aspiration biopsy (FNAB)-induced remission of primary hyperparathyroidism (PHPT) is an extremely rare and generally transient phenomenon.

Methods

A 40-year-old woman with a history of recurrent kidney stones was diagnosed with PHPT (serum calcium, 14.2 mg/dL; parathyroid hormone [PTH], 380 pg/mL). Ultrasonography and scintigraphy findings were consistent with a left enlarged parathyroid. Ultrasound-guided-FNAB cytology of the lesion did not confirm a parathyroid nature. However, levels of PTH within the needle-washing fluid were elevated.

Results

After few days, there was evidence of biochemical remission of the hypercalcemia (calcium, 8.1 mg/dL), and at subsequent follow-up visits, the enlarged parathyroid showed progressive shrinkage with eucalcemia and normalized PTH levels throughout 12 months of follow-up.

Conclusions

Rarely, remission of PHPT may occur after ultrasound-guided-FNAB performed on a hyperfunctioning parathyroid lesion.

A Functional Parathyroid Cyst from the Hemorrhagic Degeneration of a Parathyroid Adenoma

A 77-year-old man with a history of hypertension, prostate hyperplasia, and urolithiasis was admitted for acute kidney injury caused by hypercalcemia. Neck ultrasonography showed a large cyst adjacent to the right lower thyroid lobe. Although a ^99mtechnetium sestamibi scan was negative, an extremely high intracystic intact parathyroid hormone level suggested that the cyst had a parathyroid origin and that a functional parathyroid cyst was present. Immunohistochemical staining for the calcium-sensing receptor (CaSR) after right lower parathyroidectomy revealed CaSR-positive cells lining the cyst, indicating that the functional parathyroid cyst had originated from the hemorrhagic degeneration of a parathyroid adenoma.

Small nonfunctional parathyroid cysts: single institution experience

Parathyroid cysts (PCs) account for less than 1% of all parathyroid lesions and are most commonly located along thyroid lobes, rarely at ectopic sites. PCs are important because they can pose a differential diagnostic challenge against other cystic formations of the neck. PCs can be functional (elevated serum parathyroid hormone level) and nonfunctional. Four cases of nonfunctional PCs are presented. All four female patients underwent physical examination and ultrasonography of the neck with ultrasound-guided fine-needle aspiration biopsy (UG-FNA). The material thus obtained was stained by the standard May-Grünwald-Giemsa method. Parathyroid hormone level was determined in aspirate and serum, along with serum levels of total calcium, inorganic phosphates. In two asymptomatic patients, remission occurred after initial aspiration biopsy; one patient had compression syndrome with vocal cord paresis that required surgical treatment; and one patient had cyst recurrence that was surgically removed. Cystic neck masses can pose a major differential diagnostic problem considering different approach, treatment method, and preoperative and postoperative follow up. Surgical treatment is necessary in case of functional and large nonfunctional PCs (due to compression syndrome), whereas individualized therapeutic approach is used in case of small nonfunctional PCs. Ultrasonography with UG-FNA, cytologic analysis of the material obtained, and determination of parathyroid hormone level in aspirate and serum are crucial for making an accurate diagnosis.

Intrathyroidal parathyroid hyperplasia in tertiary hyperparathyroidism

We report herein a case of intrathyroidal parathyroid hyperplasia in a patient with tertiary hyperparathyroidism. The patient was recommended for parathyroidectomy due to sustained hypercalcemia after kidney transplantation. Preoperative radiologic evaluations showed a benign-looking thyroid mass and three enlarged parathyroid glands. Intraoperative intact parathyroid hormone (iPTH) level and frozen biopsy results indicated a missed parathyroid gland after immediate subtotal parathyroidectomy. Then, a secondary partial resection of thyroid including the thyroid nodule was performed. An excised intrathyroid nodule was diagnosed to be parathyroid hyperplasia by frozen biopsy, and intraoperative iPTH level abruptly decreased. A benign-looking thyroidal mass in patients with secondary or tertiary hyperparathyroidism should be carefully evaluated considering the possibility of an intrathyroidal parathyroid hyperplasia.

Intrathyroidal parathyroid glands: small, but mighty (a Napoleon phenomenon)

BACKGROUND

Intrathyroidal parathyroid adenomas (ITPAs) are a rare entity. The aim of this study is to describe the experience of 2 endocrine surgery centers and to distinguish characteristics of intrathyroidal parathyroid adenoma and nonintrathyroidal parathyroid adenomas.

METHODS

We included patients who had undergone operations for primary hyperparathyroidism who had intrathyroidal parathyroid adenomas. Patients with single intrathyroidal parathyroid adenomas were also compared to age- and sex-matched controls with nonintrathyroidal parathyroid adenomas.

RESULTS

Of 4,868 patients who underwent parathyroidectomy between January 2002 and June 2011, we identified 53 (1%) patients with intrathyroidal parathyroid adenoma. Sestamibi and ultrasound scans correctly identified the adenoma in 35 (70%) and 11 (61%) cases, respectively. Single adenomas were identified in 44 (83%) patients, double adenomas in 4 (8%) patients, and hyperplasia in 5 (9%) patients. Lobectomy was performed in 17 (32%) patients; enucleation was used in 36 (68%) patients. Cure was achieved in all patients and no patients experienced a recurrence. Patients with single intrathyroidal parathyroid adenomas had significantly smaller glands than patients with nonintrathyroidal parathyroid adenomas (325 ± 47 vs 772 ± 61 mg; P < .0001); however, no significant difference was identified between the groups with regard to demographics, symptoms, preoperative laboratory values, or outcomes.

CONCLUSION

Single intrathyroidal parathyroid adenomas are smaller than nonintrathyroidal parathyroid adenomas, but patients with intrathyroidal parathyroid adenomas present with similar laboratory values and symptoms. Recognition of this rare entity can lead to a successful surgical outcome.

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.