Colonic metastases from primary lung adenocarcinoma are rare and represent a diagnostic and management dilemma. This clinical presentation often mimics primary colonic cancer or non-malignant bowel pathology. The reported incidence of this entity is postulated to rise with the improvement in diagnostic imaging and histopathology testing. Colonic metastases from primary lung adenocarcinoma are associated with poor overall survival, as they represent an advanced pathological process with associated morbidity due to complications from the metastases. Though there is limited data on this pathological entity, if feasible, surgical resection is thought to be associated with survival benefits. We report a case of a woman in her 60s diagnosed with an isolated descending colon metastasis from a known primary lung adenocarcinoma on interval imaging. While asymptomatic at the time, the patient underwent a palliative left hemicolectomy due to the risk of luminal obstruction and perforation from the lesion if left untreated.

Lung cancer (LC) mortality exceeds 20%, and detecting metastases from LC is becoming a challenging step in understanding the real prognostic role of specific localization. We report a case of a patient with lung metastasis to the colon with local recurrence at the anastomosis after radical resection for metastasis. In both cases, the diagnosis was on oncological follow-up, and surgery was offered in consideration of reasonable life expectancy, good control of LC, and high risk of intestinal occlusion. A 67-year-old male, with a history of LC 18 months ago, was referred to our surgical unit after a positron emission tomography CT total body, where an area of intense glucose metabolism (SUV max: 35.6) at the hepatic colic flexure was reported. A colonoscopy revealed an ulcerated, bleeding large neoplasm distally to hepatic flexure, almost causing resulting total occlusion. Histologic examination revealed a tumor with complete wall thickness infiltration, which appears extensively ulcerated, from poorly differentiated squamous carcinoma (G3), not keratinizing, with growth in large solid nests, often centered by central necrosis. Two of the 30 isolated lymph nodes were metastatic. The omental flap and resection margins were free from infiltration. The malignant cells exhibited strong positive immunoreactivity only for p40. The features supported metastatic squamous carcinoma of lung origin rather than primary colorectal adenocarcinoma. After 8 months from surgery, intense Fluorodeoxyglucose (FDG) uptake of tissue was confirmed in the transverse colon. Colonoscopy evidenced an ulcerated substenotic area that involved ileocolic anastomosis on both sides. Reoperation consisted of radical resection of ileocolic anastomosis with local lymphadenectomy and ileotransverse anastomosis. The second histologic examination also revealed poorly differentiated squamous carcinoma (G3), not keratinizing, with positive immunoreactivity only for p40, suggesting the origin of LC. This case report confirmed that the possibility of colonic secondary disease should be part of the differential diagnosis in asymptomatic patients and those with a history of LC diagnosis. In addition, relapse of colonic metastasis is infrequent but should be considered during follow-up of LC. More studies on colonic metastasis of LC are required to better understand the clinical features and outcomes.

Lung cancer is the leading cause of cancer deaths worldwide. Although lung cancer can metastasize to various organs such as the liver, lymph nodes, adrenal gland, bone, and brain, metastases to the digestive organs, especially the colon, are rare.

An 83-year-old man diagnosed with lung cancer received radiation and chemoimmunotherapy, resulting in a complete clinical response. One year after the initial lung cancer diagnosis, the patient presented with obstructive ileus caused by a tumor in the descending colon. An elective left hemicolectomy was successfully performed after the endoscopic placement of a self-expandable metallic stent (SEMS). Pathologically, the tumor of the descending colon was diagnosed as lung cancer metastasis. The postoperative course was uneventful, and the patient is in good condition 13 mo after surgery, with no signs of recurrence. The previous 23 cases of surgical resection of colonic metastasis from lung cancer were reviewed using PubMed to characterize their clinicopathological features and outcomes.

SEMS is useful for obstructive colonic metastasis as a bridge to surgery to avoid emergency operations.