A case of thymoma mimicking an intra-thoracic thyroid nodule

Thymomas are rare tumours, comprising about 0,2-1,5% of all malignancies and occurring mostly in the fourth-sixth decade of life1,2. They are slow growing tumours usually located in the anterior mediastinum, typically composed by a mix of neoplastic epithelial cells originating from thymic tissue and non-neoplastic immature T-lymphocytes. Thymomas are frequently associated with neuromuscular disorders such as myastenia gravis, or with symptoms due to compression or invasion of adjacent structures (shortness of breath, wheezing, superior vena cava syndrome, etc.), but they can be asymptomatic and incidentally detected during imaging work-up. Due to the rarity and localization of these tumours, differential diagnosis between thymomas and other lesions of this region can be difficult, and their identification and staging can be particularly challenging. Imaging and histological examination are fundamental tools for an accurate diagnosis and the assessment of the extent and invasion of these tumours play a central role for the prognosis of these patients3. We report a case of a thymoma extended to the lower neck region mimicking an intrathoracic thyroid nodule, in a patient with history of thyroid surgery for hyperplastic goiter.