Single symptomatic colonic metastasis as first presentation of a pulmonary mucoepidermoid carcinoma

Metastatic lesions in the large bowel are rare. A case of single symptomatic colonic metastasis as first presentation of pulmonary mucoepidermoid carcinoma (MEC) is described. A 62-year-old male was admitted with constipation and rectal bleeding. Colonoscopy revealed extrinsic compression at sigmoid colon, and microscopy suggested a secondary origin. Subsequent chest computed tomography confirmed a right perihilar mass invading posterior mediastinum, carina and esophagus, and also a second consolidation on right lower lobe and ipsilateral mediastinal and subcarinal lymph nodes. After pathologic evaluation of a transthoracic biopsy specimen, the diagnosis of pulmonary high-grade MEC, stage IV (T4, N3, M1b - 7th ed. TNM), was established. Chemotherapy with carboplatin and paclitaxel was initiated, and disease progression occurred after two cycles with increasing colonic mass. Palliative surgery was rejected because of advanced stage, and the patient was submitted to palliative pelvic radiotherapy. Second-line chemotherapy with gemcitabine was initiated, but clinical status worsened and the patient died because of severe lung failure. Clinical, pathological and therapeutic aspects of this uncommon site of extrathoracic metastatic disease are discussed, emphasizing the important contribution of special stains and immunohistochemistry to the diagnosis.