Two patients of IgG4-related Mikulicz’s disease (IgG4-RD) with progressive transformation of germinal centers (PTGC) arising in the submandibular glands are reported.
The patients were a 58-year-old male and 39-year-old female who fulfilled the clinico-pathological diagnostic criteria for IgG4-RD, including (1) markedly elevated serum IgG4 level, (2) bilateral swelling of the submandibular and lacrimal glands, and (3) microscopic finding of an IgG4⁺/IgG⁺ plasma cell ratio of more than 40% in the germinal centers.
Histopathologically, PTGCs are characterized by hyperplastic germinal centers composed of mantle zone lymphocytes and remnant of large germinal center cells with follicular lysis.
Complete resection is the only treatment for PTGC. However, in patients with IgG4-RD, administration of a corticosteroid might be recommended and efficacious. Because of the possibility of recurrence or malignant transformation after surgery or other treatments, close follow-up is mandatory.
To the best of our knowledge based on a thorough search of the literature, there is only one report other than ours of PTGC arising in the submandibular glands in a patient with IgG4-RD.