Supplementary Material for: Minor salivary gland biopsy for the diagnosis of neurosarcoidosis

Introduction: The definite diagnosis of neurosarcoidosis is challenging since it requires a compatible histology of the nervous system. When neurosarcoidosis is suspected, other systemic manifestations are investigated to confirm the diagnosis. A minor salivary gland biopsy (MSGB) is often performed since it is minimally invasive. The objective of the present study was to assess its performance for the diagnosis of neurosarcoidosis. Methods: A retrospective single-center study included patients who underwent a MSGB in a tertiary neurological university hospital (Lyon, France) between 2015 and 2018. Clinical presentations unlikely to be compatible with neurosarcoidosis were excluded. Positive cases of neurosarcoidosis were defined as definite, probable, and possible cases, according to the latest international neurosarcoidosis diagnostic criteria from the Neurosarcoidosis Consortium Consensus Group. Results: A total of 529 patients underwent a MSGB for clinical manifestations compatible with neurosarcoidosis. Among the 13 who fulfilled the criteria for neurosarcoidosis, only one had a positive MSGB. The sensitivity of MSGB was 7.7% (95% CI [0.2–36.0%]) and the specificity was 100.0% (95% CI [99.3–100%]). Discussion/Conclusion: Considering the low sensitivity of MSGB for the diagnosis of NS, MSGB should be performed in selected indications, including a suspicion of spinal cord sarcoidosis, or when there is a strong clinical, laboratory and radiological suspicion of NS. MSGB should rather not be performed when the chest CT-scan does not show signs of pulmonary or lymph node sarcoidosis.

引言：神经结节病（neurosarcoidosis）的明确诊断颇具挑战，因其需获取符合病理学要求的神经系统组织标本。当疑似神经结节病时，临床需排查其他系统表现以辅助确诊。小唾液腺活检（minor salivary gland biopsy, MSGB）因创伤极小，常被用于此类诊断场景。本研究旨在评估MSGB用于神经结节病诊断的效能。

方法：本研究为单中心回顾性研究，纳入2015年至2018年间于法国里昂某三级神经学科大学医院接受MSGB的患者。排除临床表现不符合神经结节病特征的病例。参照神经结节病联盟共识小组（Neurosarcoidosis Consortium Consensus Group）最新发布的国际神经结节病诊断标准，将神经结节病阳性病例分为确诊、拟诊及可疑三类。

结果：共计529例因临床表现符合神经结节病特征而接受MSGB的患者。其中13例符合神经结节病诊断标准，仅1例MSGB结果呈阳性。MSGB的灵敏度为7.7%（95%置信区间[0.2–36.0%]），特异度为100.0%（95%置信区间[99.3–100%]）。

讨论与结论：鉴于MSGB用于神经结节病诊断的灵敏度较低，MSGB应仅应用于特定适应证，包括疑似脊髓结节病，或临床、实验室及影像学高度怀疑神经结节病的情况。当胸部CT未显示肺或淋巴结结节病征象时，则不宜行MSGB。