Cancer of unknown primary site in which tumor marker-oriented chemotherapy was effective and pancreatic cancer was finally confirmed at autopsy

Sequential mediastinal lymphadenectomy of an unknown primary tumor

An 83-year-old woman was admitted for lower mediastinal lymphadenopathy, detected by computed tomography; preoperative examinations did not detect a primary lesion. Fifteen months after tumor resection, a new mediastinal lymphadenopathy located 4 cm from the site of the first lesion was resected. Histopathologic and immunohistochemical examinations of both tumors revealed metastatic, poorly differentiated, adenocarcinomas with identical findings; however, the primary site could not be identified based on these examinations. The patient has remained disease-free for 23 months since the last surgery. Thus, sequential resections of metachronous mediastinal lymph node metastases from an unknown primary cancer yielded beneficial disease control.