A case of solitary nodular pulmonary amyloidosis]

A 64-year-old man without respiratory symptoms was introduced to our hospital because of a nodule of 20 mm in diameter found in the left lung in a periodic health examination. The chest radiograph and CT scan showed a well-defined nodule in the middle of the left lung field, and enlarged mediastinal lymph nodes. Lung cancer was suspected, and transbronchial and CT guided biopsies were performed, but did not lead to a definitive diagnosis. Since the patient refused further examinations, we carefully followed up the nodule in the chest radiograph. After a year and a half, the nodule and the lymph nodes became enlarged, and the patient was admitted to the hospital for a surgical biopsy. Video-assisted thoracoscopic surgery followed by thoracotomy was performed for both a biopsy and nodule resection. Histologically, the nodule tissue was rich in amorphous substances positively stained with Congo Red, which was consistent with amyloidosis. No findings of systemic amyloidosis or secondary amyloidosis were demonstrated.