患儿男，12岁，因咳嗽、发热1月余入院，起病来体重减轻2 kg。外院抗感染治疗无效，胸部影像学检查提示右肺弥漫性间质性肺水肿伴淋巴回流受阻改变，结合组织病理学等检查，诊断为肺癌合并肺癌性淋巴管炎，予多西他赛+卡铂化疗，病情仍进展，于确诊后3个月死亡。该病例提示对于持续存在呼吸道症状且病因不明的患者，不应忽视肺癌可能，同时应早期完善影像学检查，必要时进行病理检查，以实现早期发现和诊断。一旦发现肺癌性淋巴管炎表现，往往提示已进入肿瘤晚期，预后不良。

A 12-year-old boy was admitted with symptoms of cough and fever lasting over a month, accompanied by weight loss 2 kg. Prior anti-infective treatments proved ineffective in alleviating the symptoms. Chest imaging revealed diffuse interstitial pulmonary edema in the right lung with obstructed lymphatic drainage. Combined with histopathological examinations, the diagnosis was confirmed as lung cancer with pulmonary lymphangitic carcinomatosis. The patient underwent chemotherapy with docetaxel and carboplatin, yet the disease progressively worsened, resulting in death three months after diagnosis. This case highlights lung cancer should not be overlooked in patients with persistent respiratory symptoms of unknown etiology. Early imaging examinations, along with necessary pathological evaluations, are crucial for timely detection and diagnosis. The presence of pulmonary lymphangitic carcinomatosis often indicates an advanced-stage of cancer, associated with a poor prognosis.