Organizing Pneumonia as a Histopathological Term.

Area of Science:

• Pulmonology
• Pathology
• Radiology

Background:

• Organizing pneumonia (OP) is an interstitial lung disease characterized by granulation tissue in lung tissue.
• OP can be a primary condition or a secondary finding in various lung diseases.
• Understanding the clinical significance of OP lesions is crucial for accurate diagnosis and management.

Purpose of the Study:

• To examine the clinical significance of histopathological organizing pneumonia (OP) lesions.
• To analyze the clinical and radiological features of patients with primary OP.
• To differentiate between reactive OP and primary OP, including cryptogenic and secondary forms.

Main Methods:

• Retrospective evaluation of 138 patients with OP lesions from lung pathology reports (2011-2015).
• Classification of patients into reactive OP and primary OP groups based on final diagnoses.
• Radiological assessment categorized as typical, focal, or infiltrative OP; PET-CT data analyzed where available.

Main Results:

• 39% of patients had primary OP, while 61% had reactive OP, often associated with malignancy (65%) or infection (15%).
• Cryptogenic OP was more frequent than secondary OP among primary cases.
• Radiologically, focal OP (63%) was most common, often requiring surgical resection due to high SUVmax on PET-CT, suggesting malignancy.

Conclusions:

• Organizing pneumonia (OP) lesions are frequently a minor component of other underlying lung diseases.
• Cryptogenic organizing pneumonia and focal radiological patterns are common presentations.
• Focal OP lesions often necessitate surgical resection due to pre-diagnostic suspicion of malignancy, indicated by elevated PET-CT SUVmax.