Significance of Chromogranin A and Synaptophysin in Parathyroid Proliferative Lesions: Immunohistochemical Study on Parathyroid Adenoma, Atypical Adenoma, Carcinoma and Hyperplasia

Abstract

By immunostaining for chromogranin A, synaptophysin and parathyroid hormone, parathyroid proliferative lesions were compared by immunostaining patterns from normal parathyroid glands. Immunohistochemical staining for chromogranin A, synaptophysin and parathormone was performed with normal glands and proliferative lesions including 13 parathyroid adenomas, one atypical adenoma, two carcinoma and eight hyperplasia cases. Proliferating parathyroid lesions including adenoma, atypical adenoma and hyperplasia were less immunosatained for parathyroid hormone and chromogranin A than normal parathyroids. Two carcinoma cases were diffusely positive for parathyroid hormone but weakly positive for chromogranin. All normal parathyroid glands and the majority of parathyroid proliferative lesions were negatively immunostained for synaptophysin. This weakly immunostained CgA in parathyroid proliferative lesions supports autonomous parathormone and chromogranin A secretion, resulted in lesser stored parathormone in chromogranin A-containing secretory granules. Atypical adenoma case was less immunostained for parathyroid hormone and chromogranin A like the other adenomas while two carcinomas were diffusely positive for parathyroid hormone and weakly positive for chromogranin A. This different parathormone immunosataining patterns may distinguish between atypical adenoma and carcinoma. Normal glands and the majority of proliferative lesions were negative for synaptophysin and synaptophysin may not be directly involved in synthesis and secretion of parathormone in normal and proliferative parathyroid lesions.