Prevalence and Clinical Spectrum of Nonsecretory Medullary Thyroid Carcinoma in a Series of 839 Patients with Sporadic Medullary Thyroid Carcinoma

Abstract

The prevalence of nonsecretory MTC was low (0.83% of patients with MTC). Diagnosis was often made at a clinically advanced tumor stage. The histological and immunohistological characteristics and the clinical course and prognosis of nonsecretory MTC are markedly heterogeneous. A high Ki-67 PI and a large proportion of cells with RET 918 mutations are associated with a poor prognosis.