Human pulmonary dirofilariasis coexisting with intercostal neurilemmoma: a case report and literature review.

Human pulmonary dirofilariasis (HPD) is a rare zoonotic infection caused by Dirofilaria immitis. Dogs are the definite hosts and humans are infected occasionally via a vector, generally a mosquito. Most thoracic neurilemmoma arise in the mediastinum and fewer tumors originate peripherally from the intercostal nerves. Most patients with HPD or thoracic neurilemmoma are asymptomatic and these diseases are often discovered incidentally. We present a 53-year-old female who was found to have a pulmonary nodule and a chest wall nodule during a routine health examination. She underwent a video-assisted thoracoscopic surgery (VATS) with partial lung resection and local excision of the chest wall. The pathological examination revealed a coiled, degenerating Dirofilariasis immitis worm surrounded by granulomatous inflammation with caseous necrosis and a neurilemmoma composed of S-100 protein immunoreactive but smooth muscle actin negative spindle cells. Because these diseases are self-limiting and make further treatment unnecessary, video-assisted thoracoscopic surgery (VATS) is considered preferable and less invasive for definitive diagnosis and management.