This case highlights a potentially underrecognised complication – acute rectal calcinosis with ulceration in the context of parathyroidectomy due to primary hyperparathyroidism (PHPT), which is a common endocrine disorder characterised by excessive secretion of parathyroid hormone (PTH), most often due to a solitary adenoma of the parathyroid gland. Here, PTH is linked to primary hyperparathyroidism.