Recurrent granular cell tumor of the thyroid: a case report and literature review

BACKGROUND: Granular cell tumor (GCT) of the thyroid is a rare benign tumor of Schwann cell origin with a favorable prognosis and only 10 cases have been reported so far in scientific literature. The present case study describes the first case of recurrent thyroid GCT. CASE PRESENTATION: Our case describes a 20-year-old woman who had undergone lobectomy for GCT of the thyroid 4 years ago. Hematoxylin-eosin (HE) staining revealed that the lesion was composed of epithelioid cells with an abundance of eosinophilic granular cytoplasm. Immunohistochemical analysis showed that tumor cells tested positive for S-100 protein and negative for desmin. Both histological and immunohistochemical analyses supported the diagnosis of recurrent GCT of the thyroid. CONCLUSIONS: Our case suggested that a tumor-free margin excision and post-operative follow-up are necessary for the treatment of GCT of the thyroid.