A case of mediastinal hyperparathyromatosis

Area of Science:

• Endocrinology
• Surgical Pathology
• Oncology

Background:

• Recurrent hyperparathyroidism (HPT) post-parathyroidectomy is uncommon.
• Ectopic recurrence, particularly in the mediastinum, is exceptionally rare.
• Parathyromatosis, the diffuse spread of parathyroid tissue, is a potential cause.

Observation:

• A 59-year-old woman presented with recurrent HPT 13 years after a 3.5-gland parathyroidectomy.
• An incidental 1.5 x 1.3 cm pretracheal mass abutting the aortic arch was found.
• Fine-needle aspiration confirmed oncocytic cells positive for parathyroid hormone, indicating a mediastinal parathyroid nodule.

Findings:

• A sestamibi scan confirmed an avid parathyroid nodule in the mediastinum.
• The patient was asymptomatic despite multiple comorbidities.
• The lesion was located in a rare ectopic mediastinal site.

Implications:

• This case represents a unique presentation of recurrent hyperparathyroidism.
• It highlights the possibility of late ectopic recurrence due to parathyromatosis.
• The findings contribute to understanding atypical presentations of HPT and inform surveillance strategies.