What is the cause of this synchronous palpable abdominal mass in a woman recently diagnosed with lung cancer as demonstrated in Figure 1?

Key Clinical Message Colonic metastases from lung cancer are rare [1, 2]. Presentation of an abdominal mass in the setting of a new lung cancer diagnosis should prompt complete evaluation including endoscopic and CT imaging. This case also highlights the need for immunohistochemical analysis of unusual tumor deposits facilitating appropriate treatment.