YOUNG FEMALE WITH CYSTIC LUNG LESIONS: LAM OR CANNABIS-INDUCED?

Abstract

SESSION TITLE: Medical Student/Resident Lung Pathology SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Lymphangioleiomyomatosis (LAM) is a rare condition of unknown etiology, which causes cystic lung lesions in young women and often presents with dyspnea and pneumothoraces (1). CASE PRESENTATION: A 39-year-old African American female with a past medical history of asthma, marijuana use, and tobacco use presented to the Emergency Room (ER) with non-specific abdominal pain. She underwent computed tomography (CT) of her chest, abdomen, and pelvis and was incidentally found to have bilateral cystic lung lesions. Her abdominal workup was negative and she was discharged with a referral to pulmonology due to concerns for LAM. On follow-up in pulmonology clinic, her history was significant for dyspnea on exertion for several years, as well as worsening dyspnea during a recent pregnancy. A few months later, the patient presented to the ER with chest pain and was found to have a primary spontaneous pneumothorax (PSP) and a chest tube was placed and removed prior to discharge. A few weeks later the patient developed worsening chest pain and dyspnea and was found to have a recurrent pneumothorax. She underwent repeat chest tube placement and her VEGF-D was negative at that time. She underwent pleurodesis with lobectomy of her lingula, and pathology showed smoking-related mild emphysematous changes, subpleural blebs, reactive mesothelium, and no evidence of LAM. Her cystic lesions, dyspnea, and recurrent pneumothoraces were attributed to her heavy cannabis use. DISCUSSION: Our patient had characteristic findings of LAM including dyspnea, recurrent pneumothoraces, and cystic lung disease. However, her VEGF-D was negative and her lingula biopsy results revealed no evidence of LAM; therefore, she was diagnosed with cannabis cystic lung disease. Young females with cystic lung disease are frequently suspected of having LAM, which is rare. When evaluating females with cystic lung disease, common etiologies such as emphysema and cannabis cystic lung disease should be ruled out. Many case reports have documented the appearance of PSP, dyspnea, and upper to middle lobe bullous emphysema in patients who use cannabis (1,2). These findings are heightened in patients who are users of both cannabis and tobacco, such as our patient (1). The mechanism of bullae formation in cannabis users is unknown, but has been attributed to prolonged breath holding during marijuana smoking, which leads to extended exposure to inhaled toxins and subsequent loss of elastic recoil in lung tissue. The mechanism of pneumothoraces has been attributed to repeated Muller’s and Valsalva maneuvers, in addition to high inspiratory pressures causing barotrauma (3). CONCLUSIONS: Common etiologies such as emphysema and cannabis cystic lung disease should be ruled out when evaluating young females with cystic lung lesions. Reference #1: Martinasek MP, McGrogan JB, Maysonet A. A Systematic Review of the Respiratory Effects of Inhalational Marijuana. Respir Care. 2016 Nov;61(11):1543-1551. Reference #2: Underner M, Urban T, Perriot J, Peiffer G, Harika-Germaneau G, Jaafari N. Spontaneous pneumothorax and lung emphysema in cannabis users. Rev Pneumol Clin. 2018 Dec;74(6):400-415 Reference #3: Mishra R, Patel R, Khaja M. Cannabis-induced bullous lung disease leading to pneumothorax. Medicine (Baltimore). 2017 May; 96(19): e6917. DISCLOSURES: No relevant relationships by Nelly Bellamy, source=Web Response Speaker/Speaker's Bureau relationship with Theravance Please note: $1001 - $5000 Added 06/12/2020 by Edward Charbek, source=Web Response, value=Honoraria No relevant relationships by Joseph Cumming, source=Admin input no disclosure on file for Elizabeth Davaro