Atypical/bizarre spindle-cell epithelial metaplasia in nodular goiter: a potential diagnostic pitfall

Excerpt

Sir, Primitive spindle-cell tumor or tumor-like lesions of the thyroid are an uncommon finding. As far as thyroid tumors are concerned, apart from the well-known possibility that hyalinizing trabecular adenoma and anaplastic carcinomas may contain epithelial spindle cells, more rarely other tumors, such as follicular adenoma and papillary carcinoma, exhibit a metaplastic spindle-cell epithelial component [4]. In some primitive thyroid lesions, the spindle-cell component may be mesenchymal rather than epithelial in nature; this is the case of the solitary fibrous tumor and reactive lesions, such as the nodular fasciitis-like stroma of the papillary carcinoma and post-fine-needle aspiration spindle-cell nodules [1]. …