Atypical parathyroid adenoma: Series of two consecutive cases from a tertiary care hospital in Qatar

Introduction: Atypical parathyroid adenomas (APA) are an uncommon cause of hypercalcemia and comprise a minority of parathyroid adenomas. Presentation of cases: Case 1 - Egyptian male, 48 years old with history of type 2 diabetes mellitus, incidentally discovered increased serum of calcium level on routine investigation, was diagnosed as PHPT, US and MIBI scan showed large left inferior parathyroid adenoma, focused exploration and excision of the APA was undertaken, histopathology confirmed APA. Case 2 - Egyptian male, 60 years old, cardiac patient with history of diabetes, hypertension and multiple cardiac interventions, had nausea, vomiting, constipation abdominal pain, polyuria, polydipsia, and history of passing renal stones, hypercalcemia workup showed primary hyperparathyroidism (PHPT), MIBI was negative and SPECT scan suggested right inferior parathyroid adenoma, focused exploration and excision of the APA was undertaken, histopathology confirmed APA. Discussion: APA are an uncommon cause of hypercalcemia and are responsible for a minority of parathyroid adenomas. Combined US and MIBI and SPECT scans can detect APA. Focused exploration and excision of the APA under general anaesthesia can completely remove the APA. Conclusion: Awareness of the physician and a high index of suspicion to symptoms or signs that could reflect an underlying PHPT is essential. Yearly biochemical and neck US follow up are required to detect any risk of recurrence or malignancy in the long term.