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

Abstract

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.

Keywords: parathyroid disorder; parathyroid gland adenoma; parathyroid neoplasms; parathyroid pathology; water clear cell parathyroid adenoma.

Figure 1. An ultrasound of the neck shows a solid area located lateral and inferior to the left thyroid gland.

Figure 2. Technetium-99m Sestamibi (MIBI) scan showed a significant increase in uptake after 3 hours.

Figure 3. A low-power view outlining the parathyroid adenoma composed of predominantly clear cells; a small portion of residual non-neoplastic parathyroid tissue is seen, consisting predominately of chief cells (10×).

Figure 4. High-power view demonstrating water-clear cells with abundant clear cytoplasm and an overall bland architecture (40×).

Figure 5. High-power view illustrating characteristic features of large cells with optically clear cytoplasm and sharply outlined cell membranes with no significant pleomorphism or mitotic activity (60×).