An abscess is a collection of pus secondary to an immune response to a pathogen. It can occur anywhere in the body, with the skin as the most common organ involved. A lip abscess is a rare condition. Generally, it may be due to an infective agent such as a virus or bacteria entering through a skin wound, or through hematogenous spread when there is a severe underlying condition such as a general condition disorder or immunodeficiency. It requires hypervigilance during the examination and throughout the treatment course with intravenous antibiotic therapy and urgent surgical drainage, as it may cause significant complications regarding localization, lymphovascular drainage, and ultimate spread. Persistent abscess, necrotic tissue, or cavitated lesions are worrisome and it is important to rule out immunosuppression or a methicillin-resistant staphylococcus. In this case, a 22-year-old male patient with a unilateral lip abscess, misdiagnosed as an allergic food reaction, responded well to external drainage and antibiotic therapy.

Immunoglobulin G4-related disease (IgG4-RD) is a new disease entity of rare and complex immune-mediated fibroinflammatory conditions that can affect any organ. The concomitance of IgG4 sclerosing sialadenitis and dacryoadenitis with rhinosinusitis is extremely rare. We report a case of IgG4 sclerosing sialadenitis and dacryoadenitis (Mikulicz\'s disease) diagnosed in a middle-aged African American man with a long-standing history of chronic rhinosinusitis who presented with progressively worsening bilateral salivary and lacrimal glands swelling. Imaging revealed pansinusitis, symmetric enlargement of the lacrimal glands, parotid glands, and submandibular glands. Serological IgG4 level was significantly elevated and the diagnosis of IgG4 sclerosing sialadenitis was confirmed by histopathology. A robust clinical response in the facial swelling and nasal manifestations was noted after the initiation of immunotherapy with corticosteroids.

Chronic sclerosing sialadenitis (CSS) or Küttner tumor is an under-recognized, benign fibroinflammatory disease most commonly seen in the submandibular gland of older adult males. Sialolithiasis or bacterial infection was first suspected as an etiology, but CSS is now considered an immunoglobulin G4-related disease (IgG4-RD). IgG4-RD can affect almost every organ in the body, characterized by organ fibrosis with IgG4-positive plasmacytes. Numerous autoimmune-related diseases have been unified under IgG4-RD, including Mikulicz disease (MD), autoimmune pancreatitis, Reidel\'s thyroiditis, and others. In any organ, IgG4-RD can present similar to malignancy. Due to the ability to mimic malignancy, it is crucial to be aware of this under-recognized clinical entity. CSS is currently of broad and high clinical interest due to increased understanding, multiorgan involvement, and more clearly defined criteria. To increase awareness of this disease, we describe a rare presentation of CSS with a literature review.

Autoimmune diseases of major salivary glands include Sjögren\'s syndrome and a complex of disorders classified as immunoglobulin G4-related diseases. These pathologies are characterised by an autoimmune reaction mediated by T-helper lymphocytes that targets the ducts of exocrine glands in Sjögren\'s syndrome and glandular parenchyma in immunoglobulin G4-related diseases. Immunoglobulin G4-related diseases represent recently introduced multi-organ diseases that also involve the salivary glands. However, the morbid conditions once known as Mikulicz\'s disease and Kuttner\'s tumour were recently considered as two variants of immunoglobulin G4-related diseases affecting the major salivary glands ( immunoglobulin G4-related sialadenitis). This review briefly summarises the pathogenesis and clinical features of autoimmune diseases of the major salivary glands, focusing on the diagnostic and therapeutic role of sialendoscopy.
Le patologie autoimmuni delle ghiandole salivari maggiori comprendono la sindrome di Sjögren e l’insieme di condizioni morbose raccolte sotto il nome di patologie IgG4-correlate. Tanto la sindrome di Sjögren quanto le patologie IgG4-correlate sono caratterizzate da una reazione autoimmune mediata dai linfociti T-Helper il cui bersaglio è rappresentato dai dotti delle ghiandole esocrine nella sindrome di Sjögren e dal parenchima ghiandolare nelle malattie IgG4-correlate. Queste ultime, di introduzione relativamente recente, coinvolgono solitamente molti organi tra cui le ghiandole salivari. Negli ultimi anni patologie un tempo note come malattia di Mikulicz e tumore di Kuttner sono state classificate come le patologie IgG4-correlate limitate alle ghiandole salivari maggiori e denominate scialoadeniti IgG4-correlate. Questa breve revisione riassume la patogenesi e le principali caratteristiche cliniche delle ghiandole salivari maggiori sottolineando il potenziale ruolo diagnostico e terapeutico delle scialoendoscopia.

Submandibular gland is an important human function organ. With the wide application of sialoendoscope and new understanding of IgG4 related sialadenitis, a lot of submandibular glands which were previously considered to be removed are preserved. However, some submandibular glands which might be preserved are still unfortunately sacrificed. Therefore, we advocate the popularization and promotion of new knowledge and techniques and should pay more attention to the protection of the function organ of submandibular gland.
下颌下腺是人体的重要功能器官，随着唾液腺内镜的广泛应用以及对IgG4相关唾液腺炎等炎性疾病的新认识，大量原本需要摘除的下颌下腺可得以保留。然而，仍有一些本可以保留的下颌下腺被切除。本文倡导新知识、新技术的普及和推广，重视下颌下腺功能器官的保护。.