Immunoglobulin G4-related disease requiring clinical attention: A case report and review of literature

Table 2 Diagnostic pathway and key decision points for immunoglobulin G4-related cholecystitis

Diagnosis phase	Critical examination	Key decision point	Next steps in treatment
Initial suspicion	Medical history, physical examination, serum IgG4	Are there any red-flag signs of IgG4-RD?	If yes: Proceed to next step; if no: Consider alternative diagnoses
Imaging evaluation	Contrast-enhanced CT or contrast-enhanced MRI, ultrasound	Are the imaging findings consistent with IgG4-related cholecystitis?	If consistent: Obtain tissue (for histopathology); if inconsistent but high suspicion remains: MDT discussion
Pathological confirmation	Biopsy specimen or resection specimen	Are the pathological diagnostic criteria for IgG4-RD fulfilled?	If criteria are met: Confirm diagnosis (definitive diagnosis of IgG4-RD); if pathological criteria are fulfilled: Establish definitive diagnosis of IgG4-RD
Treatment monitoring	Symptoms; serum IgG4, IL-6, sIL-2R, ELR; imaging	Is there a response to the administered therapy?	Response to treatment: Supports diagnosis; no response: Re-evaluate

IgG4: Immunoglobulin G4; CT: Computed tomography; MRI: Magnetic resonance imaging; IL: Interleukin; sIL-2R: Soluble interleukin-2 receptor; ELR: Eosinophil-to-lymphocyte ratio; IgG4-RD: Immunoglobulin G4-related disease; MDT: Multidisciplinary team.