5 Discussion
IgG4-RD manifests as an autoimmune condition that prompts the growth of
masses, frequently involving multiple bodily organs including the
pancreas and the bile duct. Notably, an increase in blood serum IgG4
levels is detected in 55% to 97% of
instances[1]. However, its occurrence within the
gastric region is notably rare. Based on the 2019 American College of
Rheumatology/European League Against Rheumatism guidelines for IgG4-RD
classification, a diagnosis requires the affected organ to be
characteristic of the disease, yet the gastrointestinal system is not
encompassed within this criterion, rendering the diagnosis of IgG4-GID
challenging[5]. Conversely, if we consider the
Japanese criteria from 2011, they point towards a probable diagnosis of
IgG4-RD in our patient[6]. It was called IgG4+
isolated or solitary lesions when patients were without top 5 of typical
performance or other IgG4 associated diseases[7].
IgG4-GID is a rare condition that has been found in published case
reports. The clinical presentations of IgG4-GID have been extensively
studied and include gastric mass, ulcer, wall thickening, obstruction,
and other symptoms. However, it is rare to find solitary gastric masses
associated with IgG4-RD. To date, only 19 cases have been documented in
scientific literature and most of them were discovered during physical
examination. EUS is a popular method to further detect the mass and a
multicenter survey revealed that inflammation primarily occurs in the
muscularis propria in all cases[8]. IgG4-RID
should be considered when a solitary gastric mass is detected and is
found to originate from the muscularis propria.
A retrospective analysis of this case indicated that the gastric mass
was larger than 2 cm, accompanied by gastrointestinal symptoms, and did
not involve other organs, making resection a reasonable approach.
Additionally, IgG4+ cells can also be found in calcifying fibrous
tumour, gastric stromal tumor as well as other inflammatory and tumor
diseases. Immunostaining did not detect vimentin or CD117, and
diagnostic scans revealed the absence of disease in additional organs.
With the high serum IgG4 level of eggs, a diagnosis of food-specific
IgG4-GID is finally being considered. The mechanism of Food-specific
IgG4-RD remains unclear, and diet therapy is usually the first treatment
option, with hormone therapy even biological agents considered if
symptoms persist or show improvement.
Solitary IgG4-GID cases are uncommon and typically arise from the
muscularis propria. Diagnosis is often post-surgery, with the underlying
mechanism still unclear. Most patients do not experience recurrence
within one year of follow-up without hormone therapy. This case
emphasizes the importance of considering preoperative biopsy for lesions
originating from the muscularis propria to confirm the diagnosis and
avoid invasive procedures. The decision to initiate hormone therapy
should be made following the exclusion of non-IgG4-related diseases and
a comprehensive evaluation of symptoms, involvement of multiple organs,
and elevated serum IgG4 levels.The food-intolerance IgG4 test can be
used for further evaluation, with dietary treatment as an initial option
for asymptomatic patients.