Primary thoracic amyloidosis: Rare disease and hard diagnosis

Amyloidosis is a disease caused by extracellular deposition of complex protein-polysaccharide in a β-pleated configuration within soft tissues. Primary thoracic deposition of amyloid is scares. To explore the different thoracic manifestations of primary thoracic amyloidosis (PTA) and its diagnosis difficulty, we retrospectively analyzed cases of PTA hospitalized in our department between 2007 to 2009. PTA (AL type) diagnosis was confirmed by pathological study in all cases. All patients were investigated by chest x ray, fibrerbroncoscopy and chest and abdominal CT scan. Our study concerned 5, 63 years mean aged (34-77ans) men. PTA discovery was secondary to respiratory symptoms in 4 cases and fortuitous in 1 case. Amyloidosis was systemic in 1 case and localized to the thorax in 4 cases: 1 involved pleura, 2 involved mediastinal lymph nodes, 2 the bronchial tree and 2 the lung parenchyma. An association of 2 different thoracic localization was noted in 2 patients. The average time of diagnosis was 4 months, based on open lung biopsy in 2 cases, mediastinal lymph node biopsy in 2 cases and transthoracic lung biopsy in 1 case. Respiratory lung function was normal in 3 patients. Amyloidosis was complicated by chronic respiratory failure in 1 patient and severe obstructive disease in 1 patient. Treatment consisted in colchicin with a stable trend (1 case), systemic corticosteroids with clinical deterioration (2 cases), lung resection (2 cases). One patient disappeared during follow up. PTA diagnosis is often delayed. This is due in part to the localized feautures of amyloidosis, non specific symptoms and frequent misdiagnosis.