Benign tumor behaves malignantly: a case report of bilateral multiple pulmonary sclerosing pneumocytoma

A 66 year old was woman admitted to our respiratory department after being diagnosed with intrapulmonary metastasis of lung cancer. For further evaluation, we performed a CT guided percutaneous pulmonary puncture biopsy following the thorax-computed tomography, which revealed multiple nodules in the lung field. Histological analysis suggested that it was pulmonary sclerosing pneumocytoma. It's really hard to distinguish whether a lung lesion is malignant or benign using only a thorax-computed tomography, and an accurate diagnosis leads to the right medical decision-making. Pulmonary sclerosing pneumocytoma (PSP) is a unique, uncommon carcinoid tumor, which dominantly appears among the middle-aged women, especially the Asian women. Only a handful literature has reported PSP with lymph nodes metastasis and multicentric PSP. It has proven that it has the potential to metastasize. That is why this rare case merits our attention when we handle similar situations.