This case report presents a young female patient whose chief complaint was exertional dyspnea. Right heart catheterization confirmed severe pulmonary hypertension. Concurrently, chest CT showed atypical pulmonary parenchymal and interstitial lesions, and pulmonary function tests indicated severe impairment of diffusion capacity. To clarify whether an association existed between the lung disease and pulmonary hypertension, transbronchial lung cryobiopsy was performed, which revealed multinucleated giant cell aggregates within the alveolar spaces, with cholesterol clefts in the cytoplasm of some of them. Together with a 1-year history of pigeon exposure, the final pulmonary diagnosis was extrinsic allergic alveolitis (hypersensitivity pneumonitis).With respect to the pulmonary hypertension, genetic testing showed no significant abnormalities, thereby ruling out heritable pulmonary hypertension. After oral imatinib combined with macitentan was administered, the patient's pulmonary artery pressure gradually decreased and her symptoms recovered well; however, follow-up chest CT and pulmonary function tests showed no apparent improvement. Because the elevated pulmonary artery pressure was inconsistent with the pulmonary disease, the patient was ultimately diagnosed with idiopathic pulmonary hypertension complicated by allergic alveolitis. 本文报道1例青年女性患者，以活动后气短为主要临床表现。经右心导管检查证实存在重度肺动脉高压。同时，胸部CT存在不典型肺实质和间质病变，肺功能检查提示重度弥散功能减低。为明确肺部疾病与肺动脉高压是否存在关联，通过冷冻肺活检，提示肺泡腔内可见多核巨细胞聚集，部分多核巨细胞胞浆内见胆固醇裂隙，结合患者近1年来接触鸽子史，最终诊断为外源性过敏性肺泡炎。肺动脉高压方面，患者基因检测显示未见明显异常，排除了可遗传性肺动脉高压。给予口服伊马替尼联合马昔腾坦治疗后，患者肺动脉压力逐渐下降，症状恢复良好，但复查胸部CT及肺功能均未见明显改善，由于肺动脉压力升高与肺部疾病不相符，据此，该患者最终诊断为特发性肺动脉高压合并过敏性肺泡炎。.