Submandibular gland needle biopsy for the diagnosis of Parkinson disease

Abstract

Objective: This study investigates salivary gland biopsies in living patients with Parkinson disease (PD).

Methods: Patients with PD for ≥5 years underwent outpatient transcutaneous needle core biopsies (18-gauge or 16-gauge) of 1 submandibular gland. Minor salivary glands were removed via a small incision in the lower lip. Tissue was fixed in formalin and serial 6-µm paraffin sections were immunohistochemically stained for phosphorylated α-synuclein and reviewed for evidence of Lewy type α-synucleinopathy (LTS).

Results: Fifteen patients with PD were biopsied: 9 female/6 male, mean age 68.7 years, mean PD duration 11.8 years. Twelve of the needle core biopsies had microscopically evident submandibular gland tissue to assess and 9/12 (75%) had LTS. Only 1/15 (6.7%) minor salivary gland biopsies were positive for LTS. Five patients had an adverse event; all were minor and transient.

Conclusions: This study demonstrates the feasibility of performing needle core biopsies of the submandibular gland in living patients with PD to assess LTS. Although this was a small study, this tissue biopsy method may be important for tissue confirmation of PD in patients being considered for invasive procedures and in research studies of other PD biomarkers.

Figure 1. Needle biopsy of the submandibular gland

Figure 2. Photomicrographs of needle core tissue from submandibular gland biopsies of subjects with Parkinson disease

Sections were stained with an immunohistochemical method for phosphorylated α-synuclein (see Methods). Only structures immunoreactive for phosphorylated α-synuclein (black) and morphologically consistent with nervous tissue were considered to represent a positive biopsy finding. Sections were counterstained with Neutral Red. (A) Typical needle core tissue sample. (B) Single immunoreactive nerve fiber within a nerve fascicle running in connective tissue stroma adjacent to glandular parenchyma. (C) Single immunoreactive nerve fiber within a stromal nerve fascicle. (D) Immunoreactive puncta within the adventitia of a small artery in the stroma. (E) Several immunoreactive nerve fibers running beneath duct epithelium. (F) Immunoreactive nerve fibers interweaving among parenchymal serous gland cells. (G) Nonspecific staining (black) of hair follicle within a fragment of skin. (H) Nonspecific staining (black) of the edges of muscle fibers.