Utility of navigation system-guided submandibular gland core needle biopsy in the diagnosis of immunoglobulin G4-related sialadenitis.

Pathological diagnosis is important for the definite diagnosis of immunoglobulin G4-related sialadenitis (IgG4-RS). Core needle biopsy (CNB) is a scarless technique; however the pathological heterogeneity of IgG4-RS (a particular feature of this disease) could be the potential cause of the inferior diagnostic capability of submandibular gland CNB (SMG-CNB) for IgG4-RS. The aim of this study was to explore technical improvements in SMG-CNB and improve its diagnostic power in IgG4-RS diagnosis. Eighteen patients clinically suspected for IgG4-RS were enrolled and underwent both SMG-CNB and SMG surgical biopsy. A navigation system (Brainlab) was employed during SMG-CNB to obtain representative samples and avoid blood vessel injury. Histopathological and immunopathological findings for the SMG-CNB samples were in good concordance with SMG surgical biopsy. There was no statistically significant difference between SMG-CNB and SMG surgical biopsy in IgG-positive cell count (132.4 ± 59.3 vs 132.2 ± 47.5, P = 0.99), IgG4-positive cell count (102.2 ± 39.7 vs 97.2 ± 27.6, P = 0.67), or IgG4-positive/IgG-positive cell count ratio (78.6% ± 0.1% vs 75.2% ± 0.1%, P = 0.29). A moderate or strong significant correlation was found between SMG-CNB and SMG surgical biopsy for these cell counts and ratio (all P < 0.01). The diagnostic consistency of SMG-CNB and SMG surgical biopsy was 100%. The Brainlab navigation system may assist in collecting representative SMG-CNB samples from typical pathological lesions. Tissues obtained from SMG-CNB are sufficient for the pathological diagnosis of IgG4-RS. Standardized SMG-CNB is expected to replace SMG surgical biopsy for IgG4-RS diagnosis.