Nitrofurantoin-related organizing pneumonia

Differential diagnoses include early fibrotic changes (e.g., idiopathic or connective tissue disease- or drug-induced), metastasis, adenocarcinoma (formerly bronchoalveolar carcinoma), and others.

Lung biopsy was done with a histopathologic study revealed features that are consistent with cryptogenic organising pneumonia (including an interstitial lung tissue with patchy areas of scattered fibroblastic plugs in air spaces "Masson bodies" and mild chronic surrounding inflammation) and small reactive intraparenchymal lymph nodes.

Some authors prefer to preserve the term "cryptogenic organising pneumonia" for conditions with an unknown underlying cause, and call that with an identified cause "bronchiolitis obliterans organising pneumonia". however, it may be easier and more favourable to use the term "cryptogenic or "secondary organising pneumonia" (COP) for both. Nevertheless, with the advantage of preventing confusionit must be not confused with another separate entity called "obliterative bronchiolitis". 

So, along with the history of previous recent nitrofurantoin antibiotic treatment, and in the absence of definite evidence of other known aetiology, it is appropriate to state this condition as nitrofurantoin-related COP.

The patient clinically started to improve with treatments including steroids. She was instructed not to use nitrofurantoin anymore in general. A follow-up high-resolution CT scan was advised.

Regarding the incidental tiny hepatic lesions, the differential diagnosis would include small haemangiomas among others. Follow-up would be recommended. 

Nitrofurantoin has multiple potential pathological implications types for the lungs.