33.Parathyroid gland, carcinoma, immunoperoxidase with antibody to parathormone, microscopic
This is a parathyroid carcinoma with nests of neoplastic cells that are not very pleomorphic and that are demonstrating positive immunoperoxidase staining with antibody to parathormone. Note the bands of fibrous tissue between the nests. Parathyroid carcinomas infiltrate surrounding structures in the neck. The serum calcium can be quite high.