C-cell hyperplasia in sporadic and familial medullary thyroid carcinoma

C-cell hyperplasia (CCH) is characterized by increased mass of C-cells and has been identified as a precursor condition for medullary thyroid carcinoma (MTC). Varying proportion of MTCs is associated with CCH in different studies. This could be due to the lack of uniformity of the definitions and techniques used to identify CCH in these studies.

This study aims to study the occurrence, clinicopathological, and immunohistochemical features of CCH in MTC diagnosed during a 22-year period at a tertiary care center in North India and to review the available literature on CCH.

Eighty-seven consecutive cases of MTC were included in the study. Histological evaluation for the presence of CCH and neoplastic CCH was performed. Confirmation of CCH was done by immunohistochemistry for calcitonin and chromogranin. The presence of neoplastic CCH was correlated with clinical factors and prognostic factors.

Of 87 cases of MTC included in the study, 71 (82%) patients were sporadic and 16 (18%) had familial MTC. Neoplastic CCH was seen in 12 (75%) familial and in 9 (13%) sporadic MTC. Patients with familial MTC were more frequently associated with neoplastic CCH than sporadic MTC (P < 0.001), were younger (P < 0.001), and had more often bilateral and multifocal tumors (P < 0.001). However, there was no significant difference in mean survival time and progression-free survival in patients with and without CCH.

CCH, though more common in familial MTC, can also be seen in sporadic tumors. CCH is not associated with patient survival and disease progression.