Not All Pulmonary Nodules in Smokers are Lung Cancer

Discussion

The differential diagnosis for new multiple pulmonary nodules on imaging studies is broad and includes infectious processes, such as tuberculosis, as well as other mycobacterial, fungal, and bacterial infections. Noninfectious causes of lung disease are an even broader category of consideration. Noninfectious pulmonary nodules differential includes sarcoidosis, granulomatous with polyangiitis, hypersensitivity pneumonitis, methotrexate drug reaction, pulmonary manifestations of systemic conditions, such as RA chronic granulomatous disease and malignancy. ⁸ Bronchogenic carcinoma was suspected in this patient due to her smoking history. Squamous cell carcinoma was also considered as the lesion was cavitary. AFB and GMS stains were negative for fungi. Langerhans cell histiocytosis were considered but ruled out as these lesions contain larger numbers of eosinophils than described in the pathology report. Histoplasma and coccidiosis laboratory tests were obtained as the patient lived in a region endemic to both these fungi but were negative (Table). A diagnosis of rheumatoid nodule was made based on the clinical setting, typical radiographic, histopathology features, and negative cultures.

This case is unique due to the quality and location of the rheumatoid nodules within the lungs. Pulmonary manifestations of RA are usually subcutaneous or subpleural, solid, and peripherally located ^.9 This patient’s nodules were necrobiotic and located within the lung parenchyma. There was significant cavitation. These factors are atypical features of pulmonary RA.

Pulmonary RA can have many associated symptoms and remains an important factor in patient mortality. Estimates demonstrate that 10 to 20% of RA-related deaths are secondary to pulmonary manifestations. ¹⁰ There are a wide array of symptoms and presentations to be aware of clinically. These symptoms are often nondescript, widely sensitive to many disease processes, and nonspecific to pulmonary RA. These symptoms include dyspnea, wheezing, and nonproductive cough. ¹⁰ Bronchiectasis is a common symptom as well as small airway obstruction. ¹⁰ Consolidated necrobiotic lesions are present in up to 20% of pulmonary RA cases. ¹⁰ Generally these lesions are asymptomatic but can also be associated with pneumothorax, hemoptysis, and airway obstruction.10 Awareness of these symptoms is important for diagnosis and monitoring clinical improvement in patients.

Further workup is necessary to differentiate malignancy-related pulmonary nodules and other causes; if the index of suspicion is high for malignancy as in our case, the workup should be more aggressive. Biopsy is mandatory in such cases to rule out infections and malignancy, as it is highly sensitive and specific. The main problem hindering management is when a clinician fails to include this in their differential diagnosis. This further elucidates the importance of awareness of this diagnosis. Suspicious lesions in a proper clinical setting should be followed up by imaging studies and confirmatory histopathological diagnosis. Typical follow-up is 3 months after initial presentation to assess stability and possibly 18 to 24 months as well based on Fleischer guidelines.

Various treatment modalities have been tried as per literature, including tocilizumab and rituximab. ^11,12 Our patient is currently being treated with golimumab based on outpatient rheumatologist recommendations.

Conclusions

This case demonstrates the importance of a careful workup to narrow a broad differential. Medical diagnosis of pulmonary nodules requires an in-depth workup, including clinical evaluation, laboratory and pulmonary functions tests, as well as various imaging studies.