title: Small-cell (basaloid) thyroid carcinoma: a neoplasm with a solid cell nest histogenesis?
abstract: In the past, undifferentiated (anaplastic) carcinoma of the thyroid included a small-cell variant with either a diffuse or a compact morphology. After the mid-1980s, with the advance of immunohistochemistry, almost all those rare tumors with the former characteristic were reclassified as low-grade lymphomas and those with the latter characteristic as small-cell variants of medullary carcinoma and poorly differentiated ("insular") carcinoma. Since then, no primary thyroid small-cell carcinoma has been reported in the literature, with the exception of a case of a small-cell (neuroendocrine) carcinoma, an exceedingly rare neoplasm akin to medullary carcinoma, with expression of neuroendocrine markers but lacking calcitonin immunoreactivity. Here, the authors report a primary small-cell carcinoma of the thyroid displaying a basaloid appearance and lacking any signs of neuroendocrine or C-cell differentiation.
authors.affiliation: Hospital CUF Descobertas, Lisbon, Portugal. joao.g.cruz@jmellosaude.pt
authors.forename: João
authors.initials: J
authors.lastname: Cruz
authors.forename: Catarina
authors.initials: C
authors.lastname: Eloy
authors.forename: José Maria
authors.initials: JM
authors.lastname: Aragüés
authors.forename: João
authors.initials: J
authors.lastname: Vinagre
authors.forename: Manuel
authors.initials: M
authors.lastname: Sobrinho-Simões
mesh_terms: D000328:Adult; D018288:Carcinoma, Small Cell / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D013964:Thyroid Neoplasms / Q000378:metabolism / Q000473:pathology*