Pathology - Primary ​Hyperparathyroidism

Pathology - Primary ​Hyperparathyroidism
Resulting from PTH adenoma, PTH hyperplasia, PTH carcinoma, or the secretion of PTH-like hormone by malignancies, particularly squamous cell bronchogenic carcinoma.
Linked to Multiple Endocrine Neoplasia Type I and Type IIA.

Pathology 
Parathyroid gland: Parathyroid adenoma is a well-defined nodule consisting of homogeneous polygonal chief cells and a small number of bigger oxyphil cells.
Osseous tissue: Osteitis fibrosa cystica is characterized by cystic areas filled with fibrous tissue, known as brown tumors, due to heightened osteoclast activity.

Clinical Symptoms and Signs 

Symptoms include bone discomfort from osteitis fibrosa cystica, nephrocalcinosis, peptic ulcers, constipation, weakness, altered mental status, and polyuria.
Laboratory results: Hypercalcemia, elevated PTH levels, elevated blood alkaline phosphatase, reduced serum phosphate.

Surgical excision of aberrant glands is recommended for individuals with renal failure, osteoporosis, or substantial hypercalcemia.

Additional causes of hypercalcemia include bone cancer, multiple myeloma, sarcoidosis, milk alkali syndrome, Paget disease of the bone, hyperthyroidism, and vitamin D toxicity.