Related Experiment Video
Updated: Jun 6, 2026

Microbiological Rapid On-Site Evaluation for Pulmonary Infectious Diseases
Published on: March 1, 2024
Reversed halo sign in pneumocystis pneumonia: a case report
Hiroshi Otera1, Kimihide Tada, Toshiyasu Sakurai
1Department of Respiratory Medicine, Nishi-Kobe Medical Center, Kojidai, Nishi-ku, Kobe, Japan. h.ohtera@nmc-kobe.org
Background:
The reversed halo sign may sometimes be seen in patients with cryptogenic organizing pneumonia, but is rarely associated with other diseases.
Case Presentation:
We present a case study of a 32-year-old male patient with acquired immunodeficiency syndrome, who had previously been treated with chemotherapy for non-Hodgkin's lymphoma. A chest X-ray showed bilateral patchy infiltrates. High-resolution computed tomography revealed the reversed halo sign in both upper lobes. The patient was diagnosed with pneumocystis pneumonia, which was successfully treated with sulfamethoxazole trimethoprim; the reversed halo sign disappeared, leaving cystic lesions. Cases such as this one are rare, but show that the reversed halo sign may occur in patients who do not have cryptogenic organizing pneumonia.
Conclusion:
Physicians can avoid making an incorrect diagnosis and prescribing the wrong treatment by carefully evaluating all clinical criteria rather than assuming that the reversed halo sign only occurs with cryptogenic organizing pneumonia.
Related Concept Videos
Pneumonia I: Introduction
Risk Factors
Various factors influence the likelihood of developing pneumonia. Age plays a crucial role, with infants, children under two, and individuals over 65 at increased risk due to their...
Pneumonia I: Introduction
Pneumonia III: Complications and Assessment
Cryptococcal Meningitis
Atypical Pneumonia
Pneumonia IV: Management
Bacterial Pneumonia Treatment
For bacterial pneumonia, antibiotics serve as the cornerstone of therapy. Initial treatment often begins with empirical antibiotics, tailored to the anticipated causative organism and adjusted based on culture results. Key antibiotic choices include: