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[Inflammatory pseudotumor of the lung]
1First Department of Internal Medicine, Kagawa Medical University, Japan.
Summary
A rare inflammatory pseudotumor mimicking organizing pneumonia was diagnosed after initial steroid-resistant treatment. This lymphoplasmacytic lesion highlights the need to consider pseudotumors in refractory organizing pneumonia cases.
Area of Science:
- Pulmonology
- Pathology
- Oncology
Background:
- Organizing pneumonia (OP) is a clinicopathological pattern of lung injury.
- Steroid therapy is the mainstay treatment for OP.
Observation:
- A 76-year-old man presented with a dry cough and a left upper lobe lung mass.
- Initial transbronchial lung biopsies (TBLBs) suggested OP, but the lesion enlarged despite steroid treatment.
- Repeated TBLBs and eventual lobectomy were required for definitive diagnosis.
Findings:
- Histopathology revealed a lymphoplasmacytic inflammatory pseudotumor with organizing pneumonia.
- Immunohistochemistry confirmed polyclonal plasma cell proliferation, ruling out malignancy.
- The resected lesion showed features of inflammatory pseudotumor, not solely OP.
Implications:
- Inflammatory pseudotumors should be considered in the differential diagnosis of steroid-resistant organizing pneumonia.
- Persistent or enlarging lung lesions despite standard OP treatment warrant further investigation.
- Accurate diagnosis is crucial for appropriate management and to exclude neoplastic processes.