Pseudometastasis secondary to histoplasmosis infection: false-positive PET/CT findings

Area of Science:

• Medical Imaging
• Infectious Diseases
• Oncology

Background:

• Positron emission computed tomography (PET)/CT is a standard imaging technique for evaluating neoplastic conditions.
• Infectious processes can sometimes lead to false-positive findings on PET/CT scans, complicating diagnosis.
• Differentiating between neoplastic and infectious etiologies is crucial for appropriate patient management.

Observation:

• Two cases are presented involving false-positive PET/CT studies in a pediatric and a young adult patient.
• The false-positive results were attributed to underlying histoplasmosis infections.
• Biopsy results in both patients confirmed the presence of fungal elements consistent with histoplasmosis.

Findings:

• Histoplasmosis infection can present as a false-positive finding on PET/CT scans, mimicking malignancy.
• One patient was managed with observation, while the other received a course of itraconazole.
• Both patients showed successful management with resolving infections, confirmed by follow-up titers.

Implications:

• Clinicians should consider infectious causes, such as histoplasmosis, when interpreting potentially false-positive PET/CT scans.
• Accurate diagnosis requires integration of imaging findings with clinical presentation and microbiological/histopathological data.
• This highlights the importance of considering non-neoplastic mimics in the differential diagnosis for PET/CT abnormalities.