Laryngotracheal presentation of anaplastic thyroid carcinoma with squamous differentiation: seven cases demonstrating an under-recognized diagnostic pitfall
Abstract
Aims
To describe a series of anaplastic thyroid carcinomas that mimicked primary head and neck squamous cell carcinoma (HNSCC) by virtue of both morphology and clinical presentation.
Methods and results
Seven cases were identified in a 15-year period where a biopsy of an airway lesion that appeared to be squamous cell carcinoma was, in fact, anaplastic thyroid carcinoma. The tumours had squamous and/or spindle cell morphology, with only the squamous component being apparent in the airway biopsy. Some tumours arose within metaplastic (n = 3) or atypical (n = 3) epithelium, supporting the diagnosis of a primary mucosal tumour. Positive PAX8 (n = 5) and TTF-1 (n = 4) staining was identified.
Conclusions
An endotracheal presentation of anaplastic thyroid carcinoma with squamous morphology may be misdiagnosed as a primary head and neck squamous cell carcinoma. PAX8 and TTF-1 expression are helpful in making the distinction, but the problem lies in suspecting a thyroid carcinoma in what appears to be a straightforward diagnosis of HNSCC.
