Abstract

OBJECTIVES: Organizing pneumonia (OP) is an interstitial lung disease characterized by granulation tissue buds in alveoli and alveolar ductus, possibly accompanied by bronchiolar involvement. Histopathologically, OP may signify a primary disease and be observed as a contiguous disease or as a minor component of other diseases. In this study, the clinical significance of histopathological OP lesions and clinical and radiological features of patients with primary OP were examined.

MATERIAL AND METHODS: Between January 2011 and January 2015, of 6,346 lung pathology reports, 138 patients with OP lesions were retrospectively evaluated. According to the final diagnoses, patients were grouped as reactive OP (those with final diagnosis other than OP) and primary OP (those with OP). Patients with primary OP were classified according to etiology as cryptogenic and secondary OP. Radiological evaluation was conducted within a categorization of “typical,” “focal,” and “infiltrative.”

RESULTS: Of 138 patients, 25% were males and the mean age was 54±14 years. Pathologically, 61% of patients had reactive OP and 39% had primary OP. All reactive OP lesions were reported using surgical specimens, and the most frequent primary diagnoses were malignancy (65%), infection (15%), interstitial lung diseases other than OP (7%), and bronchiectasis (5%). Other diagnoses included bullae, foreign body, hamartoma, bronchogenic cyst, and bronchopleural fistula. Of all the primary OP patients, 48  had cryptogenic OP and six had secondary OP. Radiological involvement was consistent with typical OP in 30%, focal OP in 63%, and infiltrative OP in 7% of the patients. All focal OP lesions were defined using surgical resections. Positron emission computed tomography (PET-CT) was recorded in 28 patients. In 11 patients, lymphadenomegaly was comorbid. The mean widest diameter of focal opacity was 2.7±1.2 (1.2-4.9) cm, and the mean the maximum standardized uptake value (SUVmax was 6.1±3.9 (1.7-16.7).

CONCLUSION: OP lesions generally present as a minor component of other diseases. In patients with OP, cryptogenic OP and radiological focal OP is more frequently observed. Most focal OP lesions are detected using surgical resections because of malignant prediagnosis owing to elevated SUVmax. 

Cite this article as: Tokgöz Akyıl F, Ağca M, Mısırlıoğlu A, et al. Organizing Pneumonia as a Histopathological Term. Turk Thorac J 2017;18:82-7.