Section: Endocrine Sub-section: Parathyroid

Overview

Very rare
Can present with extreme hypercalcaemia, severe bone disease, or renal stones.
Other symptoms include weakness, extreme tiredness, confusion, nausea and vomiting, weight loss, polyuria
50% of patients will present with a palpable neck mass (which never occurs with an adenoma).

Causes

Association Hyperparathyroidism-Jaw Tumour syndrome
- Germline CDC73 mutations
  - Encode a protein parafibromin which is a tumour suppressor gene - many sporadic cancers also exhibit mutations in this gene.
- Parafibromin is stained for on histology - as malignant tumours generally have loss of parafibromin.

Appear as greyish-white, and adherent to adjacent structures, like the thyroid, trachea, and neck muscles.
Histology
- Bizarre nuclear atypia
- Mitotic figures
- Capsular invasion
Only definitive criteria for malignancy
- Local invasion
- Metastatic disease
  - Lung, liver, LNs

Must be prepared to do oncologic resection if required on exploration
- Classically find adherence to surrounding structures or invasion intra-operatively, with dense scarring
If suspected pre-op
- “At risk group”
- Severe hypercalcaemia, very high PTH, and palpable tumour
Perform En-bloc resection of parathyroid tumour, ipsilateral thyroid lobe, ipsilateral parathyroid, and adjacent nodes
- May have to sacrifice RLN if invaded
Routinely explore contralateral parathyroids
If diagnosis made post-op after parathyroidectomy
- Re-operate and remove ipsilateral thyroid and parathyroid, and LNs