A Rare Case of Isolated Chronic Cough Caused by Pulmonary Lymphangitic Carcinomatosis as a Primary Manifestation of Rectum Carcinoma

A 36-year old man was referred to our hospital due to isolated chronic cough that was refractory to anti-asthma medications, including inhaled corticosteroids/long-acting β(2) agonists. Chest X-ray showed diffuse nodular and enhanced vascular shadows with Kerley lines in both lungs. A blood analysis showed elevated serum carcinoembryonic antigen (CEA) and CA19-9 levels. A transbronchial biopsy revealed well to moderately differentiated adenocarcinoma, the origin of which was immunohistochemically suspected to be the gastrointestinal tract. Colonoscopy confirmed the diagnosis of primary rectum carcinoma. Pulmonary lymphangitic carcinomatosis was therefore regarded as the origin of the cough. Lymphangitic carcinomatosis is an uncommon diagnosis but important to consider in patients with persistent cough.