An interesting case of mucinous lung adenocarcinoma complicated by cryptococcal pneumonia

SESSION TITLE: Chest Infections Case Report Posters 14 SESSION TYPE: Case Report Posters PRESENTED ON: 10/09/2023 02:10 pm - 02:55 pm INTRODUCTION: Among the rarest of pulmonary malignancies is mucinous adenocarcinoma, making up less than 2% of lung cancer diagnoses.1 Equally uncommon is Cryptococcus neoformans pneumonia in non-HIV patients without other underlying immunodeficiency.2 Both can present similarly and behave aggressively. Unfortunately, nonspecific symptoms and radiologic mimicry can lead to delayed diagnosis. We present a case of this exceedingly rare dual diagnosis. CASE PRESENTATION: A 69-year-old male with past medical history of hypertension, hyperlipidemia, and benign prostatic hyperplasia presented to the emergency department from a pulmonologist's office for a lung biopsy for evaluation of possible cryptogenic organizing pneumonia (COP). He had persistent productive cough, exertional dyspnea, and weight loss of 28 kg over one year. Multiple empiric courses of antibiotics were unsuccessful. The patient is a non-smoker, without recent travel, and works at a local grocery store. He reported minimal exposure to birds and mold, but no other exposures. He required 2L oxygen to maintain a normal oxygen saturation. Lung exam was significant for inspiratory crackles and expiratory wheezes bilaterally. Chest x-ray showed dense bilateral mass-like consolidations with mid and lower lobe preponderance. He was started on methylprednisolone given ongoing hypoxemia potentially due to inflammatory process. He underwent bronchoscopy and transbronchial biopsy, identifying mucinous pulmonary adenocarcinoma of right lower lobe, positive for CK7 and Napsin-A. His hypoxemia improved and was discharged on oral steroids. After discharge, culture grew Cryptococcus neoformans, so he was started on fluconazole 400 mg daily as an outpatient. His serum cryptococcal antigen level was 1:27. Work up for neurologic cryptococcal infection was negative. DISCUSSION: Pulmonary cryptococcus superimposed on mucinous adenocarcinoma is particularly uncommon. Literature review reveals only a few documented case reports. Specifically, cryptococcus in non-HIV and non-solid organ transplant patients is very uncommon, and so was a difficult diagnosis to anticipate in this patient. Additionally, the imaging findings were atypical for pulmonary cryptococcosis, usually presenting as pulmonary nodules5, but was seen as multifocal consolidations and ground glass opacities in this case. Advanced malignancy appeared to be the only potential risk factor for cryptococcal infection as the patient was not on long-standing immunosuppressive medications on presentation. CONCLUSIONS: Difficulty arises in this case due to the rarity of both diseases. A high level of suspicion and workup is required for one of the presenting processes let alone both, making this patient's presentation more difficult. REFERENCE #1: Benesch, M. G. K., & Mathieson, A. (2020). Epidemiology of Mucinous Adenocarcinomas. Cancers (Basel), 12(11). doi:10.3390/cancers12113193 REFERENCE #2: Pappas, P. G. (2013). Cryptococcal infections in non-HIV-infected patients. Trans Am Clin Climatol Assoc, 124, 61-79. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/23874010 REFERENCE #3: Harada, T., Hakuma, N., Kamimura, A., Ito, K., & Okamoto, K. (2006). Pulmonary cryptococcosis within a pulmonary carcinoma-review of reported cases. Intern Med, 45(6), 369-372. doi:10.2169/internalmedicine.45.1571 DISCLOSURES: No relevant relationships by Valerie Cluzet No relevant relationships by Michael Gwiazdowski No relevant relationships by Sarah Loftus No relevant relationships by Richard Merrill No relevant relationships by David Michael No relevant relationships by Hector Ojeda-Martinez