Background@#
Immunoglobulin G4 (
IgG4)-related
disease is an entity that can involve the
thyroid gland. The spectrum of
IgG4-related
thyroid disease (
IgG4-RTD) includes
Hashimoto thyroiditis (HT) and its fibrotic variant, Riedel
thyroiditis, as well as Graves’
disease. The
early diagnosis of
IgG4-RTD is important because it is a medically treatable
disease, and a delay in the
diagnosis might result in
unnecessary surgery. We present a case series of
IgG4-RTD with a
review of the
literature. @*
Methods@#We retrospectively reviewed the clinical presentation and the radiological and pathological findings of
patients diagnosed with
IgG4-RTD between 2017 and 2021 at a tertiary medical center in
Korea. We also conducted a
literature review of
IgG4-RTD. @*Results@#Five
patients were diagnosed with
IgG4-RTD during the study period. The
patients’ age ranged from 31 to 76 years, and three
patients were
men. Most
patients visited the clinic for a
neck mass, and hypoechogenic nodular lesions were observed on
neck ultrasonography. Three
patients had
IgG4 HT, and two
patients had
IgG4 Riedel
thyroiditis. All
patients developed
hypothyroidism that necessitated L-thyroxine replacement. The
diagnosis of
IgG4-RTD was confirmed after a pathological examination of the surgical specimen in the first two cases. However, the
early diagnosis was possible after a
core needle biopsy in three clinically suspected
patients. @*Conclusion@#The
diagnosis of
IgG4-RTD requires clinical suspicion combined with
serology and histological analyses using
IgG4 immunostaining. The
early diagnosis of
IgG4-RTD is difficult; thus,
biopsy with
IgG4 immunostaining and
serum IgG4 measurements
will help
diagnose patients suspected of having
IgG4-RTD.