Benign schwannoma of posterior mediastinum accompanied by bloody pleural effusion misdiagnosed as solitary fibrous tumor: A case report

Difficulty Breathing or Just a Case of the Nerves? Incidental Finding of Primary Pleural Schwannoma in a COVID-19 Survivor

Schwannoma is a rare tumor that arises from the Schwann cells, which are specialized, myelin-producing cells of the peripheral nerve sheaths. As anatomic logic would dictate, these masses commonly occur in the skull base, cerebellopontine angle, and posterior spinal roots. Of this already rare entity, rarer still are the pleural schwannomas, representing approximately 1-2% of thoracic tumors. These tumors commonly affect adults with a propensity for the third and sixth decades of life and a comparative male predilection. Schwannomas are benign, indolent, and follow an asymptomatic course. As such, they often come to light incidentally. Here we report a case of primary pleural schwannomas in a 68-year-old female, found incidentally on a CT scan of the chest. To the best of our knowledge and literature review, no other similar case has been reported in our country, Pakistan. Around three weeks before her presentation, she was diagnosed with COVID-19. Her infection had run a mild course with quick recovery without the need for any hospitalization. Therefore, the manifestation of shortness of breath after resolution of all other symptoms prompted a further workup. Radiographic chest x-ray revealed an incidental finding of a large right upper lobe lung mass, slightly impinging on the trachea. This was followed by a chest CT scan at our radiological imaging facility, which showed a large, well-encapsulated, right upper lobe lung mass in the paraspinal apical location. She then underwent an image-guided biopsy of the aforementioned mass, pathological analysis of which was suggestive of a benign peripheral nerve sheath tumor (PNST) arising from the pleura (pleural schwannoma). She underwent right posterolateral thoracotomy with uneventful complete surgical removal of the pleural-based lung mass. Postoperative investigations included a chest x-ray that showed interval complete resection of the mass. Currently, she is asymptomatic and her clinical condition has improved with the successful resumption of her daily routine. Physicians thus need to keep pleural schwannomas in mind as a probable diagnosis of intrathoracic tumors. Indolent and asymptomatic, they are very amenable to surgical resection with little to no chances of recurrence in the long term. However, these patients should be closely followed with repeat imaging studies when symptomatic.