Mediastinal lymph node carcinoma of an unknown primary site: clinicopathological examination

Purpose  We examined the clinicopathological features of four mediastinal lymph node carcinomas from an unknown primary site. Methods  Four patients with mediastinal lymph node carcinoma from an unknown primary site were treated at our hospital during the past 6 years. Results  All of the patients were men, with an average age of 74.0 years (range 70–78 years). Histologically, one lesion was poorly differentiated adenocarcinoma, two were poorly differentiated squamous cell carcinoma, and one was undifferentiated carcinoma. Radical resection of the mediastinal tumor and radiotherapy were performed in two patients, both of whom were still alive with no evidence of recurrence at 44 and 82 months, respectively, after the operation. Thoracoscopic biopsy was performed in two patients, and both underwent chemoradiotherapy. These two patients were alive at 24 and 33 months, respectively, after the biopsies. Conclusion  Radical resection of mediastinal lymph node carcinoma with an unknown primary site has the possibility of a good prognosis. In nonradical cases, it is important to perform a biopsy to make an accurate diagnosis and then administer radiotherapy and/or chemotherapy postoperatively.