Hereditary lysozyme amyloidosis with sicca syndrome, digestive, arterial, and tracheobronchial involvement: case-based review

Lysozyme amyloidosis (ALys) is a rare autosomal dominant hereditary systemic amyloidosis associated with a large spectrum of clinical manifestations. ALys phenotype mainly involves the digestive tract, liver and spleen, kidneys, lymph nodes, skin, and lachrymal and salivary glands. Very recently, cardiac involvement and peripheral neuropathy associated with a new p.Leu102Ser variant of lysozyme have been documented. In the present observation, we extend the phenotypic heterogeneity of ALys to the tracheobronchial tree with histologically proven bronchial ALys-amyloid deposits. We report the case of a 62-year-old man of Italian origin (Piedmont) diagnosed with ALys associated with the p.Trp82Arg variant. The patient complained of upper digestive symptoms, sicca syndrome, and lately recurrent pulmonary infections. Thoracic endoscopy revealed a fragile, inflammatory, and granulomatous aspect of the bronchi. Amyloid deposits were observed in the upper digestive tract, salivary glands, temporal artery, and tracheobronchial tree. Symptomatic treatment was offered. Recurrent pulmonary infections occurred during the follow-up. Lung involvement in hereditary ALys has only been exceptionally described. Although vascular involvement has already been reported in ALys in many organs, it never concerned cranial arteries. This case highlights the systemic nature of the amyloid protein variant deposits and expands the spectrum of clinical manifestations to chest involvement. The literature review highlights that hereditary ALys with the p.Trp82Arg variant is frequent in patients coming from Piedmont (Italy). Due to diffuse organs involvement related to ALys, it is important not to misdiagnose ALys for AL amyloidosis, the most frequent form of amyloidosis.