Unusual Thyroid Nodule: A Case of Symptomatic Thyroid Schwannoma.

Primary thyroid schwannoma is a sporadic non-epithelial tumor of the thyroid gland. Most previous cases reported in the literature presented it as an asymptomatic neck mass. In this report, we describe a rare case of thyroid schwannoma in a 33-year-old female, presented as a left-side neck swelling, accompanied by a change in voice and difficulty swallowing. An ultrasound of the mass showed a large heterogeneous, predominantly cystic, nodule; in contrast to the usual predominantly solid nodule described in the literature. After several pre-operative diagnostic tests, including fine needle aspiration (FNA), the diagnosis remained unclear. In the end, the patient underwent a successful surgical excision of the mass, and the diagnosis of schwannoma was confirmed based on the histopathologic examination which revealed both type A and B Antoni cells as well as positive staining for S-100 protein.