A80-3-43 A Fungal Facade: Pulmonary Mucinous Adenocarcinoma Masquerading as Infection

Abstract Pulmonary mucinous adenocarcinoma of the lung is a rare and distinct type of adenocarcinoma with computed tomography (CT) chest findings of ground glass opacities (GGOs) and eventually progress to consolidation without treatmen. Due to their unique presentation, it often mimics pneumonia. We present a 30-year-old male, former smoker with 2 pack years, with medical history including drug overdose anoxic brain injury with previous tracheostomy complicated by esophageal stenosis requiring esophageal dilation every six months, vocal cord paralysis, high risk for aspiration initially presented to a community pulmonologist with incidental finding of right middle lobe (RML) opacity on chest x ray. Follow up CT chest showed interval progression with suspicious cavitation. Bronchoscopy was discussed with patient, but he declined due to high risk for general anesthesia. Continued surveillance imaging over the next 2 years noted progressions of GGOs and tree-in-buds in right lower lobe (RLL) and enlargement of the RML consolidation. Due to progression despite multiple antibiotic courses for pneumonia and development of dyspnea on exertion, he was referred to us for bronchoscopy. Patient underwent bronchoscopy with Bronchoalveolar lavage (BAL) which grew Candida dubliniensis. Patient started on amoxicillin-clavulanate, prednisone, sulfamethoxazole-trimethoprim and voriconazole, however, he did not improve. Due to concern for malignancy, repeated bronchoscopy with transbronchial biopsy was performed, which showed atypical papillary proliferation. Case was presented to tumor board and recommend to repeat biopsy. Repeated third bronchoscopy with cryobiopsy which resulted atypical type 2 pneumocyte compatible with adenocarcinoma. Attempt at starting patient on treatment was pursued, but due to significant deterioration of patient’s respiratory status, effective treatment was not able to be performed, and patient ultimately passed away. This case notes a clinically difficult patient where obtaining a tissue diagnosis was the major difficulty due to patient’s history and anatomy. On progression of radiographic findings, there is a noted discrepancy between tissue and radiographic diagnosis, or fungal versus malignant. CT imaging more suggested a fungal etiology, compatible with initial culture diagnosis of C. dubliniensis, and patient had initial improvement with fungal treatment. Final tissue pathology identified atypical type 2 pneumocytes, compatible with adenocarcinoma. This discrepancy in a young person with minimal smoking history highlights another challenge presented in this case. Mucinous adenocarcinoma often presents with consolidations, ground glass opacities and multifocal nodular lesions, often mimicking pneumonia. In the literature, there is little comparable cases of young patients without significant smoking or environmental exposure, only 2 similar cases of adolescent patients This abstract is funded by: None