Hi there. The most common sites of cancer spread or metastasis of primary lung cancer are to the lymph nodes, liver, bones, brain and adrenal glands. so there is no distal mets to the colon. On the other hand, the most common types of cancers spreading to the lung are colon, breast, prostate and bladder. Symptoms of cancer metastatic to lungs are similar to primary lung cancer including, cough, coughing up blood, chest and back pain and shortness of breath. The differentiating symptom is with metastatic lung cancer patients have symptoms related to the primary cancer in addition to lung symptoms along with general symptoms of fatigue, weight loss and decreased appetite. this could be a primary in the colon causing a metastasis to lungs and symptoms need to be correlated. The lump on lung could be due to copd. Multiple pulmonary nodules are commonly encountered in metastatic disease of the lungs. The nodule could be both benign and malignant and based on studies a solitary pulmonary nodule measuring 11 to 20mm in diameter, prevalence of malignancy could be up to 60percent. The common causes and differentials for benign solitary pulmonary nodules are healed granulomas, active granulomatous infections like TB, hamartomas, lung fibrosis, lung abscesses,bronchogenic cysts, hemangiomas. Predictors of malignancy are old age, current or past history of smoking, history of extrathoracic cancer, or spiculation in the nodule and upper lung lobe location.
CT chest with thin sections through the nodule is recommended, with contrast enhancement if the renal function is intact, transthoracic needle biopsy or bronchoscopy to confirm the diagnosis unless contraindicated. All these findings need to be correlated clinically. Consult an oncologist with your concerns. Hope this helps. Take care.