In the presence of multiple pulmonary nodules (MPN), we must bear in mind some details regarding the differential diagnoses :
- According to patient's medical history, the semiology of the described nodules are compatible with metastatic lesions. Also the possibility of a primary pulmonary lesion could not be dismissed, although the x-ray presentation is not the typical one. According to pheochromocytoma antecedent, SPECT was made. It was negative, however it does not discard malignancy (Fig 3).
- Rheumatoid nodules, nodular sarcoidosis or other inflammatory diseases may cause MPN. Other less frequent entities include vasculitis, pneumoconiosis and amyloidosis. However, laboratory and clinical parameters were not suggestive of such entities.
- Granulomatous diseases (e.g. tuberculosis), septic embolism, lung abscess, fungal or viral infections and other parasites may cause MPN. However, radiological signs are not typical of any of them and the clinical and laboratory data were not suggestive of such possibilities.
- Vascular malformations should have been observed in previous studies. Pulmonary infarction may cause MPN but the patient did not presented pulmonary embolisms.
Due to lack of specificity of findings, multidisciplinary committee agreed to perform CT-guided pulmonary biopsy of the largest lesion (Fig. 2c).
First biopsy cylinder was successfully obtained. However immediately, the patient developed an intense cough associated with hemoptysis that required postural measures, oxygen therapy and aspiration of material accumulated in the bronchial tree. Procedure was then stopped.
Tissue obtained by fine needle aspiration biopsy shows typical findings in pulmonary amyloidosis (Fig. 4): normal lung is replaced by a mass of amorphous, eosinophilic, extracellular material Congo red-positive.
First control of pulmonary nodules 5 months after detection has shown no changes.
The most frequent form of pulmonary amyloidosis is nodular amyloidosis [2, 3] and it is usually a local process. Its x-ray appearance may be indistinguishable from neoplastic lesions. It may appear as solitary or multiple pulmonary nodules, which are rounded and well-defined. Cases of irregular edges are usually due to vascular involvement or to involvement of adjacent septa. Lesions generally grow slowly and have therefore a good prognosis.
Diffuse septal involvement (amyloid deposits in alveolar septa) is less frequent, although it is associated with higher clinical involvement due to a higher risk of pulmonary hypertension and respiratory insufficiency . In such cases, a much more varied semiology may be found: micronodules (2-4 mm), septal thickening, reticular opacity, basal peripheral consolidations that tend to converge, pleural effusion, pleural thickening, etc.