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IgG4 inflammatory pseudotumor mimicking primary lung cancer
Tomás Seip1, Francisco Calderón Novoa2, Melina Paula Valeo Chulvi3
1Hospital Italiano de Buenos Aires. tomas.seip@hospitalitaliano.org.ar.
Summary
Immunoglobulin G4-related disease (IgG4-RTD) can manifest as a lung pseudotumor, mimicking cancer. This rare condition requires consideration in differential diagnoses for lung masses.
Area of Science:
- Immunology
- Pathology
- Pulmonology
Background:
- Immunoglobulin G4-related disease (IgG4-RTD) is a rare fibroinflammatory condition.
- It can affect multiple organs and present with diverse clinical features.
- Diagnostic criteria for IgG4-RTD are still evolving due to its heterogeneity.
Observation:
- A 48-year-old smoker presented with symptoms suggestive of a lung tumor.
- Imaging revealed a right upper lobe mass with increased PET-scan SUV and mediastinal lymphadenopathy.
- A right upper lobectomy was performed, suspecting primary lung cancer.
Findings:
- Histopathological examination showed abundant IgG4 plasma cells (74% IgG4/IgG ratio).
- Absence of cellular atypia and intense plasmacytic activity led to the diagnosis of IgG4-related pseudotumor.
- Literature review revealed limited similar cases of IgG4-lung pseudotumor without systemic involvement.
Implications:
- IgG4-related pseudotumor is a benign condition that can mimic primary lung cancer.
- It should be included in the differential diagnosis of lung masses, especially in the absence of malignancy.
- Increased awareness and accurate diagnosis are crucial for appropriate patient management.
