Case reports in infectious diseases · 2026
Pulmonary Nocardia paucivorans Infection Mimicking Lung Cancer in an Immunocompetent Patient: A Case Report.
СтатьяНазвание и аннотация: Перевод в очереди
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Mekhail Mario, Shiah Kevin, Aravagiri Arunmozhi, Weng Bruce, Sutjita Made
Аннотация
BACKGROUND: Pulmonary nocardiosis is uncommon and usually affects immunocompromised hosts, but it can occur in immunocompetent patients and mimic primary lung malignancy clinically and radiographically.
CASE PRESENTATION: A 52-year-old immunocompetent woman presented with one month of cough, hemoptysis, and mild shortness of breath after repeated hiking exposures in Mexico and Central California. Chest CT showed bilateral apical ground-glass opacities and a spiculated, pleural-based mass involving the right upper and lower lobes, raising concern for primary lung cancer. HIV testing was negative; HbA1c was 5.1%; and initial sputum, blood, and acid-fast bacilli studies were negative. CT-guided biopsy showed acute and chronic inflammation, necrosis, and stromal fibrosis without well-formed granulomas. Gram stain identified Gram-positive rods. Tissue culture grew Nocardia paucivorans, identified by MALDI-TOF MS and confirmed by DNA sequencing. Susceptibility testing showed TMP-SMX susceptibility. She received prolonged oral TMP-SMX from November 2022 through December 2024, with resolution of cough and hemoptysis. Serum creatinine rose mildly during therapy but normalized without interruption. Follow-up CT showed improvement in the dominant mass, with residual bilateral upper-lobe abnormalities favored to represent postinflammatory fibrosis.
CONCLUSION: Pulmonary Nocardia paucivorans infection can closely mimic lung cancer, even in immunocompetent hosts. When noninvasive testing is unrevealing, tissue biopsy may be necessary for diagnosis. Radiological follow-up after treatment is warranted to exclude occult malignancy masked by infection.
CASE PRESENTATION: A 52-year-old immunocompetent woman presented with one month of cough, hemoptysis, and mild shortness of breath after repeated hiking exposures in Mexico and Central California. Chest CT showed bilateral apical ground-glass opacities and a spiculated, pleural-based mass involving the right upper and lower lobes, raising concern for primary lung cancer. HIV testing was negative; HbA1c was 5.1%; and initial sputum, blood, and acid-fast bacilli studies were negative. CT-guided biopsy showed acute and chronic inflammation, necrosis, and stromal fibrosis without well-formed granulomas. Gram stain identified Gram-positive rods. Tissue culture grew Nocardia paucivorans, identified by MALDI-TOF MS and confirmed by DNA sequencing. Susceptibility testing showed TMP-SMX susceptibility. She received prolonged oral TMP-SMX from November 2022 through December 2024, with resolution of cough and hemoptysis. Serum creatinine rose mildly during therapy but normalized without interruption. Follow-up CT showed improvement in the dominant mass, with residual bilateral upper-lobe abnormalities favored to represent postinflammatory fibrosis.
CONCLUSION: Pulmonary Nocardia paucivorans infection can closely mimic lung cancer, even in immunocompetent hosts. When noninvasive testing is unrevealing, tissue biopsy may be necessary for diagnosis. Radiological follow-up after treatment is warranted to exclude occult malignancy masked by infection.