Lewy pathology of the submandibular gland in Lewy body disease: A report of autopsy cases.

Accumulation of phosphorylated α-synuclein in the central and peripheral nervous systems is a histological hallmark of Lewy body disease (LBD), including Parkinson's disease (PD), dementia with Lewy bodies (DLB), and LB-related pure autonomic failure. The submandibular gland is employed as a biopsy site for detecting Lewy pathology; however, the incidence of Lewy pathology in this region in autopsy-proven LBD cases at all stages from an aged Japanese cohort remains unclear. To validate the utility of Lewy pathology of the submandibular gland as a diagnostic biomarker for LBD, we investigated the submandibular gland Lewy pathology in autopsied patients. To determine the specificity, we prospectively evaluated the submandibular gland in 64 consecutive autopsied patients. To determine the sensitivity, we retrospectively assessed the submandibular gland in 168 consecutive autopsied patients who had prodromal or clinical LBD. In the prospective study, Lewy pathology was found in 21 of 64 patients, and nine of those 21 patients had the submandibular gland Lewy pathology. No Lewy pathology was found in 43 patients without CNS Lewy pathology, giving a specificity of 100%. In the retrospective study, Lewy pathology of the submandibular gland was detected in 126 of 168 patients. The sensitivity was 89.1% in PD and 75.4% in DLB. The sensitivity increased with disease progression. These findings support the utility of the submandibular gland biopsy for the pathological diagnosis of LBD.