Cannabinoids Identification in Lung Tissues of Young Cannabis Smokers Operated for Primary Spontaneous Pneumothorax and Correlation with Pathologic Findings

Background: Several studies suggested the association between tobacco and cannabis smoking and the risk of primary spontaneous pneumothorax (PSP), but none demonstrated cannabinoids in human lung tissues. Objectives: The aim of this study was to identify cannabinoids in lung specimens of young cannabis smokers, operated for PSP, and investigate on their pathologic findings, to determine the role of cannabis in PSP pathogenesis. Method: A prospective, multicenter study was conducted, enrolling patients admitted for PSP. Inclusion criteria were PSP requiring surgical treatment and history of cannabis smoking, associated or not to tobacco. Control cases were nonsmokers, and tobacco only smokers operated for PSP. Lung apex wedge resection by video-assisted thoracic surgery was performed. Two lung specimens, for pathological and toxicological examination, were taken from each patient. Results: Twenty-nine male patients were enrolled: 21 (72.4%) tobacco and cannabis smokers, 2 (7%) cannabis only smokers, 3 (10.3%) tobacco only smokers, 3 (10.3%) nonsmokers; all underwent lung apicectomy, 4 bilateral surgery, for a total of 33 procedures. Typical PSP pathologic findings were mainly detected in control cases, other alterations in cannabis users. Lung specimens resulted positive for cannabinoids on 22/33 cases (19/22 reported being, 3/22 not being cannabis smokers), negative on 11/33 (3/11 reported not being, 7/11 having been cannabis smokers, 1/11 cannabis smoker). Conclusions: Our study demonstrated the presence of cannabinoids and particular pathologic alterations in lung tissues of young cannabis smokers with PSP, supporting the correlation between this disease and marijuana abuse and suggesting spontaneous pneumothorax “secondary to marijuana” as a new nosological entity.