Abstract:

Objective To improve the clinical understanding for pulmonary Langerhans cell histiocytosis (PLCH), including their clinical, radiological and pathological features and prognosis. Methods Retrospective analysis of 36 patients diagnosed with PLCH and hospitalized in The First Affiliated Hospital of Guangzhou Medical University between September 2009 and August 2019 was conducted. HRCT scores (using the Muller scoring method) of nodular lesions, cystic lesions and pulmonary interstitial lesions were compared. According to results of transbronchial lung biopsy (TBLB) at the first time,the patients were divided into two groups: positive TBLB result group (11 patients) and negative TBLB result group (8 patients). According to the level of eosinophilic infiltration in lung pathology,the patients were divided into two groups:higher eosinophilic infiltration group (18 patients) and lower eosinophilic infiltration group (13 patients). According to the prognosis, PLCH patients were divided into two groups: survival group (32 patients) and death group (4 patients).The clinical characteristics of those groups were compared. Results The median age of 36 patients with PLCH was 27.50 (19.50,36.75) years old. 55.56% (20/36) patients had spontaneous pneumothorax. The median HRCT total score of 36 patients was (6.71±2.84). The median HRCT scores of nodular lesions, cystic lesions and pulmonary interstitial lesions were 2.67 (0.67,4.33), 3.67 (1.75,4.33) and 0.00 (0.00,1.92), respectively, and the difference between them was statistically significant (χ²=18.000,P<0.001). HRCT score of cystic lesions was negatively correlated with the percentage of predicted value of forced expiratory volume in 1 second (FEV₁%pred) and forced expiratory volume in 1 second/forced vital capacity (FEV₁/FVC) (r_s=-0.527,P=0.008;r_s=-0.440,P=0.032, respectively). Nineteen patients underwent TBLB, and 57.89% (11/19) patients obtained positive pathological results of PLCH at the first time of TBLB. The average percentage of predicted value of diffusion capacity for carbon monoxide of lung-single breath method (DLCO SB%pred) among this positive TBLB result group was (75.19±11.91) %, significantly higher than that of the negative group ((55.43±17.10) %, t=2.449, P=0.032). The average HRCT score of pulmonary interstitial lesions in the positive group was 0.00, significantly lower than that in the negative group (4.50 (0.00, 4.92),P=0.020). In the lung pathological tissues of PLCH, 61.11% (11/18) of the patients with higher eosinophilic infiltration had nodular lesions, significantly higher than those with lower eosinophilic infiltration (15.38% (2/13),P=0.025). 4 (11.11%, 4/36) patients died and all the dead patients (100.00%) were diagnosed as multi-system PLCH, which was significantly higher than that in the survival group (31.25% (10/32),P=0.017). Conclusion For patients with pneumothorax as the main clinical manifestation, cystic and nodular lesions as the main radiological findings, with/without multi-system involvement, the possibility of PLCH should be considered. TBLB was recommended for suspected PLCH patients with better diffusion function and no interstitial lesions in HRCT. Multi-system involvement was the adverse factor of prognosis.

Key words: Lung, Pulmonary langerhans cell histiocytosis, Pneumothorax, Eosinophilia, Pathology, Respiratory Function Tests