Mediastinal recurrence after curative resection of colon cancer: A case report and review of literature.

Colorectal carcinoma is one of the most common and significant causes of cancer-related death. Metastasis to mediastinal lymph nodes and/or pleura without liver or lung involvement is an atypical pattern of colon cancer metastasis. A 70-year-old male underwent curative right side hemicolectomy and omentectomy for ascending colon cancer followed by adjuvant chemotherapy. Around nine months after surgery, the patient was noted to have bilateral large pleural effusions on the restaging computed tomography scan of the chest/abdomen/pelvis. No intraabdominal or intrathoracic mass/metastasis was seen on the imaging. Multiple thoracentesis performed over the course of next few months revealed exudative effusion but failed to demonstrate malignant cells. A few months later, new mediastinal and right hilar lymphadenopathy was noted on the repeat computed tomography scan. A subsequent positron-emission tomography scan revealed multiple sites of fluorodeoxyglucose (FDG)-avid mediastinal lymphadenopathy. The sites of pleural effusion were not fluorodeoxyglucose-avid. Endobronchial ultrasound and biopsy of mediastinal nodes showed adenocarcinoma with signet-ring features. Immunohistochemistry confirmed the diagnosis of metastatic colon cancer. Systemic treatment with chemotherapy was initiated. Our case highlights the importance of mediastinal evaluation by imaging during the follow-up of patients with colorectal carcinoma. The ideal management strategy for mediastinal metastasis of colorectal carcinoma remains a question, two major options being local metastasectomy or systemic chemotherapy.