A CASE OF MISTAKEN IDENTITY: PULMONARY BLASTOMYCOSIS DIAGNOSED AS PULMONARY CRYPTOCOCCOSIS

Abstract

TOPIC: Chest Infections TYPE: Medical Student/Resident Case Reports INTRODUCTION: Community acquired pneumonia (CAP) has a wide range of differential diagnosis with high potential for misdiagnosis. We report a case of Blastomycosis in an Appalachian hunter who was misdiagnosed with bacterial and Cryptococcal pneumonia. This case highlights the importance of evaluating CAP etiologies based on patients' epidemiological risks. CASE PRESENTATION: A 32-year-old West Virginian man with a history of recurrent sinusitis, body-mass index of 18, current smoker, and avid hunter presented with dyspnea and dry cough. Initially, at an outside facility 3 weeks prior, chest x-ray showed a left upper lobe consolidation. He was prescribed a 10-day course of levofloxacin and steroid taper, but his symptoms did not improve. Further evaluation with computed tomography (CT) chest showed a 1.6-centimeter necrotic lymph node in the subcarinal area and consolidation in the left upper lobe and lingula. He was admitted and received empiric intravenous vancomycin, piperacillin-tazobactam, and azithromycin. Severe acute respiratory syndrome coronavirus 2 and human immunodeficiency virus tests were negative. Initial pathology read of lingula biopsy was stratified squamous epithelia with enmeshed clusters of cysts with double walls and inclusion bodies suggestive of Cryptococcus neoformans. Antibiotics were discontinued and fluconazole was started, but he developed a fever of 103⁰ Fahrenheit. Then, he was transferred to our hospital for further management. Serum Blastomyces and Histoplasma antigens were positive. Silver staining of the original biopsy specimen showed a thick-walled yeast and broad-based budding forms suggestive of Blastomyces. Fluconazole was changed to itraconazole. The patient improved and resumed daily activities. DISCUSSION: It is important to consider individual patients' risk factors to aid in narrowing the broad differential diagnosis for CAP to minimize morbidity. In this case, the patient was empirically treated for bacterial CAP despite having no improvement after taking levofloxacin, a broad-spectrum antibiotic. Differential diagnoses should include fungal etiology due to the patient's hunting history. Identifying the fungus is important, especially in Blastomycosis since it is often missed, which leads to delay in diagnosis, inappropriate treatment, and disease progression. CAP diagnosis is made with visualization of the fungus due to cross-reactivity in serologic tests. Treatment is specific to the organism. Cryptococci spp. are encapsulated, narrow-based budding yeasts, found in immunocompromised patients, and treated with fluconazole. However, Blastomyces are broad-based budding yeasts, found in areas surrounding the Ohio and Mississippi River valleys, and treated with itraconazole. CONCLUSIONS: It is important to consider individual patients' risk factors to aid in narrowing the broad differential diagnosis for CAP to minimize morbidity. REFERENCE #1: Guarner J, Brandt ME. Histopathologic diagnosis of fungal infections in the 21st century. Clin Microbiol Rev. 2011;24(2):247-280. doi:10.1128/CMR.00053-10 REFERENCE #2: Kanjanapradit K, Kosjerina Z, Tanomkiat W, Keeratichananont W, Panthuwong S. Pulmonary Cryptococcosis Presenting With Lung Mass: Report of 7 Cases and Review of Literature. Clin Med Insights Pathol. 2017;10:1179555717722962. Published 2017 Aug 4. doi:10.1177/1179555717722962 REFERENCE #3: Martynowicz MA, Prakash UB. Pulmonary blastomycosis: an appraisal of diagnostic techniques. Chest. 2002;121(3):768-773. doi:10.1378/chest.121.3.768 DISCLOSURES: No relevant relationships by Allison Lastinger, source=Web Response No relevant relationships by Shu Xian Lee, source=Web Response No relevant relationships by Yusra Shah, source=Web Response