The most common underlying aetiology of primary hyperparathyroidism is
The underlying aetiology of PHPT is usually a solitary parathyroid adenoma, however, in a small number of patient (2-4%), there are double adenomas. It may occur in a sporadic fashion or it can be familial (MEN type 1 or type 2A, hyperparathyroidism-jaw tumour syndrome (HPT-JT)Ref: Bailey and Love 27e pg: 826
Parathyroid adenoma
MEN-1
MEN-2A
Parathyroid adenocarcinoma
Endocrinology and breast