Pneumocystis pneumonia with multiple nodules on computed tomography.

Area of Science:

• Medical Imaging
• Infectious Diseases
• Hematology

Background:

• Pneumocystis pneumonia (PCP) is a significant opportunistic infection.
• Multiple nodules on computed tomography (CT) are atypical findings for PCP, particularly in non-human immunodeficiency virus (HIV) cases.
• Patients undergoing hematopoietic stem cell transplantation (HSCT) are at increased risk for opportunistic infections like PCP.

Purpose of the Study:

• To report a unique case of PCP presenting with multiple pulmonary nodules in a patient post-HSCT.
• To emphasize the importance of considering PCP in the differential diagnosis of multiple pulmonary nodules in immunocompromised patients.
• To illustrate the radiological resolution of atypical PCP findings following appropriate treatment.

Main Methods:

• Case report of a 47-year-old female with acute myeloid leukemia post-HSCT.
• Diagnostic workup included computed tomography (CT), serological markers (elevated β-d glucan), and molecular testing (PCP PCR on bronchial lavage fluid).
• Clinical diagnosis of PCP was made based on symptoms, imaging, and laboratory findings, despite atypical nodular presentation.

Main Results:

• CT revealed multiple nodules and segmental consolidation with subpleural sparing.
• The patient's condition was refractory to levofloxacin.
• PCP was confirmed by positive PCR on bronchial lavage fluid.
• Treatment with trimethoprim/sulfamethoxazole led to the resolution of both nodules and consolidation on follow-up CT.

Conclusions:

• Pneumocystis pneumonia (PCP) should be considered in the differential diagnosis of multiple pulmonary nodules detected on CT in patients who have undergone hematopoietic stem cell transplantation (HSCT).
• Atypical presentations of PCP, such as multiple nodules, can occur and resolve with appropriate antimicrobial therapy.
• This case underscores the need for a high index of suspicion for PCP in immunocompromised patients presenting with unusual radiological findings.