Primary mediastinal lymph node malignancy with features suggestive of dendritic cell sarcoma.

A 56-year-old man underwent preoperative chest computed tomography to further evaluate a well denned mass in the middle lobe with subcarinal lymph node swelling. There was no pathological diagnosis established by either bronchoscopic biopsy specimens or computed tomography-guided percutaneous needle biopsy. The middle lobe and mediastinal lymph nodes were excised, then postoperative radiotherapy (60 Gy) was administered to the mediastinum. Results of histological and immunohistochemical study showed that the lung mass consisted of completely necrotic tissue and that the subcarinal lymph node was involved by malignant cells suggestive of dendritic cell sarcoma. Primary dendritic cell sarcoma of the mediastinal lymph node is extremely rare. Dendritic cell sarcoma is a neoplasm of reticular dendritic origin and includes both follicular dendritic cell sarcoma and interdigitating reticulum (or dendritic) cell sarcoma. These rare neoplasms may pose difficulty in pathologic diagnosis and treatment. Although our patient died of hepatic rupture due to dendritic cell sarcoma or gastric cancer metastases one year after surgery, complete surgical resection with or without postoperative radiotherapy may be an acceptable therapeutic option for localized dendritic cell sarcoma.