[Medullary thyroid carcinoma. Immunohistochemical markers in histopathology and research]

Medullary thyroid carcinoma, a tumour derived from the calcitonin-producing C cells, is a rare tumour. Nevertheless it has evoked considerable interest in the past two decades amongst pathologists, clinicians, and human geneticists. Medullary thyroid carcinoma occurs either sporadically or as part of the inherited MEN II syndromes. The introduction of sensitive biochemical screening tests for the detection of early, clinically occult disease, and the advent of specific immunohistochemical staining methods have proved ideally for the study of this tumour. Immunohistochemical confirmation of the diagnosis of medullary thyroid carcinoma and the demonstration or exclusion of concomitant C cell hyperplasia (which precedes medullary thyroid carcinoma) are regarded as mandatory. Immunohistochemical markers used in routine histopathology and/or research of medullary thyroid carcinoma are reviewed and briefly discussed in the present paper.