A 83-year-old man was admitted to the hospital with complaints of cough and breathlessness for 68 days before, and the chest X-ray films showed a rather well-circumscribed round shadow, 11 by 9.5cm in size, in the middle field of the right lung. He died in pulmonary failure with downhill course. Retrospectively the chest X-ray film before nine and a half months had indicated the abnormal shadow suggesting a minute tumor in the same region.
On postmortem examination, an adult-fist sized, soft, fairly well-circumscribed and centrally necrotic tumor with pleural infiltration was found in S-6 of the right lung, and histologically this tumor was identified as the reticulosarcoma without metastasis anywhere.
This case may be the second case of the primary reticulosarcoma of the lung exactly described in Japan.