A comparison of the pathological, clinical and radiographical, features of cryptogenic organising pneumonia, acute fibrinous and organising pneumonia and granulomatous organising pneumonia.

AIMS

Cryptogenic organising pneumonia (COP) and acute fibrinous and organising pneumonia (AFOP) are recognised patterns of organising pneumonia (OP), a condition that resembles pneumonia but is not caused by infection. We have recognised granulomatous organising pneumonia (GOP) to be a similar histopathological entity where non-necrotising granulomata are intimately associated with the organising connective tissue. To what degree COP, AFOP and GOP represent distinct clinical and pathological disorders is unknown. This cross-sectional study sought to compare the pathological, clinical, and radiographical features of these OP patterns.

METHODS

Surgical lung biopsy specimens were reviewed for consecutive patients referred with OP to a metropolitan cancer centre. Clinical information and CT images were acquired from the hospital electronic medical record to determine the clinical and CT characteristics of each OP pattern.

RESULTS

Sixty-one patients (35 men, 26 women), mean age 61.5 years (range 8-85 years), were available for analysis. Of these, 43 patients (70%) had at least one prior cancer; 27 (44%) had received chemotherapy and 18 (30%) had received radiation. Approximately, half (32 patients) had respiratory symptoms, most commonly cough, dyspnoea and/or wheezing. While symptoms and mortality rates were not different among OP groups, AFOP patients more commonly had fever (p=0.04). GOP patients less commonly had received chemotherapy (p=0.03) and were more likely to present as masses/nodules (p=0.04).

CONCLUSIONS

AFOP and GOP, a newly described OP form, possess clinical and pathological findings that set it apart from a COP, suggesting an emerging spectrum of OP.