C80-52 Lung Adenocarcinoma Presenting as Large Granuloma: A Diagnostic Dilemma

Abstract Introduction Lung adenocarcinoma may mimic infectious diseases as both entities may present with cough, dyspnea and other constitutional symptoms such as fever, weight loss and body malaise. Pneumonic-type lung adenocarcinoma, although rare, may appear as lobar consolidations on chest radiographs posing a diagnostic challenge. Case Report We present a case of a 57-year old Filipino male, previous smoker, who presented with 3-month history of recurrent productive cough associated with intermittent fever and weight loss. On initial consult, chest radiograph showed presence of consolidation-atelectasis on the right mid lung. Chest CT scan revealed lobar consolidation of the right middle lobe with multiple calcifications and heterogenous enhancement. Primary consideration was a large granuloma formation from pulmonary tuberculosis. Scattered few fibrotic densities and parenchymal nodules on both lungs were noted as well. Sputum TB Gene Xpert was negative for Mycobacterium tuberculosis DNA. Patient was managed as Clinically Diagnosed Pulmonary Tuberculosis and was started on Isoniazid, Rifampicin, Pyrazinamide and Ethambutol. However after completion of the 2-month intensive phase of anti-Koch’s regimen, cough and dyspnea persisted. There was no significant change on the lobar consolidation on Xray as well. Bronchoscopy with bronchial washing was then performed. Bacterial culture studies showed heavy growth of Acinetobacter baumanii and Klebsiella pneumoniae. Antibiotics were given which provided temporary relief. AFB smears, TB Gene Xpert, and KOH yielded negative results. CT-guided biopsy of the mass was also performed and histopathologic result showed cytomorphologic features consistent with primary lung adenocarcinoma with neuroendocrine features; proliferation index using KI-67 was <5%. Metastatic workups were done and oncology referral was facilitated. Discussion In the Philippines, lung cancer is the second most prevalent type of cancer in the country, but it remains as the leading cause of cancer-related death. Lung adenocarcinoma is a relatively common subtype however it may present with different clinical and radiographic features causing a diagnostic challenge especially in resource-limited settings. Due to the high TB burden in the country, patients presenting with granuloma formation and other radiologic findings suggestive of tuberculosis are clinically managed as such. However high index of suspicion must be given in cases unresponsive to medications as lung cancer may present with benign features such as consolidations or calcifications as well. Delay in diagnosis may lead to disease progression and poor outcomes. This abstract is funded by: None