Labial salivary gland biopsy for diagnosis of amyloid polyneuropathy

Biopsies of peroneal nerve and labial salivary gland (LSG) were performed in 32 patients with polyneuropathy of unknown origin. Amyloid deposits were detected in 7 LSG (transthyretin=5; amyloid, light chain derived=2) and 6 nerve biopsies. Familial amyloid and light chain amyloid polyneuropathies were subsequently confirmed by relevant tests. We propose that LSG biopsy, a minimally invasive test that may document both sicca syndrome and amyloidosis, should be systematically performed in the investigation of patients with axonal polyneuropathies.