Presentation of Lung Carcinoid Tumor as Post-obstructive Pneumonia

Carcinoid tumors consist of neuroendocrine cells that produce amines, polypeptides, and prostaglandins. The majority of carcinoid tumors are found in the gastrointestinal system while a minority originate as pulmonary neoplasms. Among lung cancers, carcinoid tumors are rare, compromising 1-2% of lung malignancies in the United States. Lung carcinoid tumors are characterized into typical and atypical classifications. Typical lung carcinoid tumors are often lower grade, slower growing, and more well-defined than atypical tumors. Atypical tumors are also more likely to metastasize than their typical counterparts. The patient presented in this article is a 35-year-old male with a history of recent hospital admission for pneumonia who presented with right chest pain. The patient was admitted eight days prior due to cough and acute hypoxemic respiratory failure secondary to post-obstructive pneumonia. During that admission, which totaled five days, he underwent a bronchoscopy and biopsy for a nodular right infrahilar opaque mass that appeared on computed tomography angiography of the chest. After the workup was negative, the patient was discharged. Three days later, he was re-admitted with continued chest pain. Biopsy results from the initial admission characterized the obstructing infrahilar mass as a carcinoid tumor with positive synaptophysin/ chromogranin stain and low proliferation (Mib1 < 2%). Following his discharge three days later, he was seen in follow-up by cardiothoracic surgery and underwent further imaging studies. Two months later, the patient underwent robotic right middle and lower bilobectomy. Pathologic analysis showed negative excised nodes and tumor margins. Often, patients presenting with post-obstructive pneumonia are thought to have an underlying etiology that is purely infectious. This can lead to a delay in the discovery of the primary cause of the obstruction, and the underlying malignancy. Fortunately for this case, a biopsy was performed during the initial hospitalization, which led to a modification of his treatment plan early on in his second hospital stay after the tumor was characterized.