A 52-year-old woman presented with a painless right thyroid mass of 4 months duration, with a recent increase in size in the last few weeks. The neoplasm was characterized by bland spindle cells with a low mitotic rate arranged around vascular elements of variable shape and caliber. Multiple immunohistochemical stains failed to show evidence of epithelial. neuroendocrine, or specific mesenchymal differentiation. Electron microscopic studies revealed spindle cells with micropinocytotic vesicles, surrounded by variable but sometimes abundant basement lamina-like material. To the authors' knowledge, this is the first report of a typical hemangiopericytoma of the thyroid gland. This lesion must be distinguished from epithelial and neuroendocrine tumors with spindle cells and from other mesenchymal neoplasms that may occur in the thyroid.
- Electron microscopy
ASJC Scopus subject areas
- Pathology and Forensic Medicine