Large Water-Clear-Cell Parathyroid Adenoma: A Report of a Rare Case.

Water-clear-cell parathyroid adenomas are extremely rare tumors characterized by cells that contain clear, foamy cytoplasm. Here we report a case of a large water-clear-cell parathyroid adenoma in a 70-year-old male. The patient was presented to an outside hospital with severe abdominal pain and supporting CT imaging confirming a small bowel obstruction. Initial laboratory studies revealed hypercalcemia and elevated parathyroid hormone levels. Subsequent ultrasound imaging revealed a 2.7 × 2.1 cm neck mass suspicious for a parathyroid adenoma. A parathyroidectomy was performed, and microscopic evaluation revealed an expansile proliferation of cells with characteristic water-clear cell features. Although rare, water-clear-cell parathyroid adenomas are clinically indistinguishable from more common subtypes and should be considered in the differential diagnosis of an anterior neck mass.