[Case of pulmonary dirofilariasis with cavity formation in a young woman].

A 22-year-old woman was referred to our hospital because of an abnormal shadow in her chest X-ray found on a medical examination. Chest CT showed a 16-mm nodule with cavity formation in the left lung. We did not reach a definitive diagnosis by blood test and bronchoscopy. Because we could not exclude the possibility of a malignancy, lung partial resection was performed by video-assisted thoracoscopic surgery for treatment and diagnosis. We recognized the Dirofilaria immitis by pathological diagnosis and we diagnosed this case as pulmonary dirofilariasis. It seemed to be a valuable case that the patient was young, at 22 years old, and there was, cavity formation, which is comparatively rare in pulmonary dirofilariasis.