# A Rare Case of Hypercalcemia from Mediastinal Ectopic Hyperparathyroidism

## TL;DR

A rare case of high blood calcium was caused by a parathyroid tumor in an unusual location in the chest, requiring urgent surgery for recovery.

## Contribution

Presents a rare clinical case of mediastinal ectopic parathyroid adenoma causing hypercalcemia.

## Key findings

- Hypercalcemia was caused by a mediastinal ectopic parathyroid adenoma between the left atrium and pulmonary artery.
- Surgical removal of the ectopic gland led to significant improvement in symptoms.
- The case highlights challenges in diagnosing and treating ectopic hyperparathyroidism.

## Abstract

Hypercalcemia is frequently attributed to primary hyperparathyroidism, commonly a result of parathyroid adenomas. Ectopic hyperparathyroidism is characterized by hyperfunctioning parathyroid tissue located outside of expected anatomical locations of endocrine tissue. In this report, we present a rare case of hypercalcemia secondary to a mediastinal ectopic parathyroid adenoma, located between the left atrium and pulmonary artery. Given the unique location of the ectopic gland, diagnosis was delayed with additional complications that followed due to difficulty accessing the gland surgically. Despite this, urgent surgical removal of the ectopic gland allowed for remarkable improvement in presenting symptoms. This clinical case highlights diagnostic and therapeutic challenges that present a unique situation worthy of clinical discussion.