Pleural amyloidosis does not present with specific imaging findings and is difficult to diagnose unless pleural biopsy is performed. However, distinguishing pleural amyloidosis from malignant disease is important and biopsy should be performed wherever possible to establish a treatment plan as early as possible.

Amyloidosis is caused by abnormal protein deposition in various tissues, including the lungs. Pulmonary manifestations of amyloidosis may be categorized by areas of involvement, such as parenchymal, large airway and pleural involvement. We describe four distinct manifestations of amyloidosis involving the lung and review their clinical, radiological and pathological features and summarize the evidence for treatment in each of these presentations. We describe alveolar-septal amyloidosis, cystic amyloid lung disease, endobronchial amyloidosis and pleural amyloidosis.

A 76-year-old male was admitted to our hospital for progressive bilateral pleural effusion. Because of typical echocardiographic findings such as left ventricular (LV) hypertrophy, thickness of the mitral valve, and a granular sparkling appearance of the LV wall, amyloid cardiomyopathy was suspected. Regardless of up-titration of several diuretic agents, the bilateral pleural effusion did not improve. Because the histological findings of the right ventricular septum (direct-fast-scarlet staining) obtained by biopsy that demonstrated amyloid deposits in perivascular and pericellular lesions, amyloid cardiomyopathy was diagnosed. However, cardiac catheterization revealed normal right and left atrial pressure and normal right and left ventricular end-diastolic pressure. Therefore, hemodynamic deterioration was less likely to be the cause of persistent pleural effusion. Amyloid deposits were also detected in the pleural biopsy specimen, so pleural amyloidosis was diagnosed and may have played an important role in the refractoriness of the pleural effusion. .

We herein report an asymptomatic 65-year-old male with localized pleural amyloidosis mimicking malignant pleural mesothelioma. He had a history of exposure to asbestos and was admitted for investigation of an abnormal pleural thickness detected by chest radiography. Positron emission tomography showed elevation of standardized uptake value corresponding to the pleural thickness. Partial pleurectomy including the tumor was performed for the purpose of diagnosis and local disease control. The pathological examination showed that the tumor was pleural amyloidosis. The tumor was diagnosed as localized primary amyloidosis, because serum monoclonal protein concentration did not increase. Pleural amyloidosis should be considered as a differential diagnosis from pleural mesothelioma.

Amyloidosis may involve the respiratory system with different clinical-radiological-functional patterns which are not always easy to be recognized. A good level of knowledge of the disease, an active integration of the pulmonologist within a multidisciplinary setting and a high level of clinical suspicion are necessary for an early diagnosis of respiratory amyloidosis. The aim of this retrospective study was to evaluate the number and the patterns of amyloidosis involving the respiratory system. We searched the cases of amyloidosis among patients attending the multidisciplinary rare and diffuse lung disease outpatients\' clinic of Pulmonology Unit of the Hospital of Arezzo from 2007 to 2012. Among the 298 patients evaluated during the study period, we identified three cases of amyloidosis with involvement of the respiratory system, associated or not with other extra-thoracic localizations, whose diagnosis was histo-pathologically confirmed after the pulmonologist, the radiologist, and the pathologist evaluation. Our experience of a multidisciplinary team confirms that intra-thoracic amyloidosis is an uncommon disorder, representing 1.0% of the cases of rare and diffuse lung diseases referred to our center. The diagnosis of the disease is not always easy and quick as the amyloidosis may involve different parts of the respiratory system (airways, pleura, parenchyma). It is therefore recommended to remind this orphan disease in the differential diagnosis of the wide clinical scenarios the pulmonologist may intercept in clinical practice.