Unexpected Tumor: Primary Asymptomatic Schwannoma in Thyroid Gland

The discovery of a tumor as a primary schwannoma in the thyroid gland is rare (Andrion et al. in Virchows Arch 413:367-372, 1988). It represents less than 1 % of mesenchymal neoplasms of this gland. Therefore, few cases of this type are described in medical literature (Aron et al. in Cytopathology 16:206-209, 2005; Cashman et al. in Medscape J Med 10(8):201, 2008; Coleman et al. in AJR Am J Roentgenol 140:383-7, 1983). In this article, we introduce the clinical case of a 27-year-old female patient, who presented a nodular mass located in the neck region. This mass was not associated with other symptoms and during the imagistic investigation it appeared to be a thyroglossal duct cyst. A fine needle aspiration biopsy was performed which revealed benign mesenchymal cells. After a pathology study of the piece resected through a thyroidectomy, it was confirmed that the tumor had neural characteristics, the final diagnosis being a primary schwannoma. The importance of a cytology study is emphasized, since in this case, it made it possible to accurately diagnose a mesenchymal tumor, despite their low frequency. It constitutes a highly useful tool for diagnosing non-epithelial neoplasia of the thyroid gland.