SUSTENTACULAR CELLS OCCUR FREQUENTLY IN THE FAMILIAL FORM OF MEDULLARY-THYROID CARCINOMA

The presence and distribution of S-100-immunoreactive sustentacular ce lls were investigated by immunohistochemistry in 67 medullary thyroid carcinomas (MTCs). The familial or sporadic status of the tumours was assessed by clinical data and confirmed by the identification of RET g ermline mutations using the polymerase chain reaction-single-strand co nformation polymorphism (PCR-SSCP) and restriction analysis. Sustentac ular cells were detected in 19 tumours (28.3 per cent). They were foun d significantly more frequently in the familial (15/24, 62.5 per cent) than in the sporadic MTCs (4/43, 9.3 per cent). The results indicate that sustentacular cells are commonly found in familial MTC and their presence in any MTC may be regarded as an indirect indicator that the tumour might be of the familial type. (C) 1998 John Wiley & Sons, Ltd.