Distant recurrence from thymoma biopsy seeding: a case report

Although some evidence shows an increase in its incidence, epithelial thymic tumors that comprise thymomas, thymic neuroendocrine tumors and thymic carcinomas, are rare (ranging from 2.5-2.8 per million). Thymomas, as presented in this paper, although slow growing lesions are malignant tumors, as the potential to invade surrounding structures and metastasize has been proven. In this case report, we present another feature of these neoplasms, recurrence. Although local and regional are far more frequent, distant can also occur. We present a case of late extra-thoracic recurrence associated with seeding from a preoperative biopsy, a very rare, but real scenario, that needs to be taken into account when deciding the need for invasive staging.

We present a case of a 75-year-old woman who was sent for evaluation of painful palpable extra-thoracic nodules, 8 years after a type A thymoma excision. After image reconstruction, surgical exploration and detailed clinical history and record examination, it was considered as recurrence associated with seeding from preoperative biopsy. She had been followed with regular computed thoracic tomography imaging, with no signs of recurrence during the 5-year period, at the moment of oncological follow-up discharge.

This case is a statement for the changes that have been made in diagnosis, treatment and follow-up of epithelial thymic tumors in the last years. Nowadays, the biopsy is not proposed when a resectable epithelial tumor of the mediastinum is the probable diagnosis, as the case presented. We believe that a longer follow-up for these patients is needed as they can recur later than the initially considered 5-year period, and the absence of surgical excision of the biopsy tract or in the presence of a complex biopsy (involving, for example, pleural puncture), should possibly be considered a pseudo-R0.