A case of Warthin-like papillary thyroid carcinoma with diffuse sclerosing stroma and a novel RET mutation: a new entity or a combined tumour?

Activating mutations of the RET gene have been described for both papillary (chromosomal rearrangement) and medullary (missense mutations) thyroid carcinomas. Here, we describe a case of a Warthin-like variant of papillary thyroid carcinoma displaying some morphological aspects that mimic the diffuse sclerosing variant. The tumour harboured BRAF V600E mutation and a novel germline point mutation in the RET gene, with unknown clinical and pathological meaning.