eng Science and Education Publishing American Journal of Medical Sciences and Medicine 2327-6657 2022-05-18 10 2 40 43 10.12691/ajmsm-10-2-1 AJMSM20221021 article Luis M. Nieto dr_luismiguelnieto@hotmail.com 1 Sharon Narvaez 2 Sinetsehay Temesgen 2 Pooja Singh 2 Israel Orija 2 Department of Internal Medicine, WellStar Atlanta Medical Center, Atlanta, Georgia, USA Facultad de Ciencias Medicas, Universidad de Guayaquil, Ecuador Primary hyperparathyroidism is a common manifestation of parathyroid disease. Atypical parathyroid adenoma and parathyroid carcinoma are rare causes of primary hyperparathyroidism and pathologic differentiation is challenging. A 44-year-old Caucasian female presented with abdominal pain, nausea, and vomiting. Her serum calcium, intact PTH, and lipase levels were elevated at presentation. Radiological assessment revealed a parathyroid mass. After parathyroidectomy, pathology demonstrated an atypical parathyroid adenoma. We present a case of primary hyperparathyroidism due to an atypical parathyroid adenoma associated with acute pancreatitis. Concurrence of severe hypercalcemia in the setting of atypical parathyroid adenoma and acute pancreatitis is very uncommon, with a small number of reported cases. http://pubs.sciepub.com/ajmsm/10/2/1/ajmsm-10-2-1.pdf primary hyperparathyroidism atypical parathyroid adenoma acute pancreatitis