Background. Mediastinal masses are relatively uncommon. For those which present as supraclavicular mass are often managed as tuberculosis or thymoma.
Case. We present a case of a 24 year old male who presented with mass at the left supraclavicular area for five years. He was initially treated as a case of PTB. A series of chest x-ray done showed an increasing soft tissue mass density extending from supraclavicular area down to the level of the aortic arch in the middle mediastinum. CT scan revealed multi loculated mass in the left infrahyoid and adjacent to the left carotid midline structure to the right; the left thyroid gland appears compressed; findings suggestive of thymic cyst. An excision of the mass was done and revealed mature cystic teratoma arising from the thymic tissue. Likewise, cell block and cytology revealed content of epithelial cyst with squamous and probable glandular elements.
Conclusion. In patients presenting with supraclavicular mass, one has to consider teratoma as one of the possible differential diagnosis. In such patients, additional work-ups, such as chest CT scan can help in the diagnosis. Surgical excision is often curative.