Occurrence of anaplastic large cell lymphoma following IgG4-related autoimmune pancreatitis and cholecystitis and diffuse large B-cell lymphoma.

IgG4-related sclerosing disease is an established disease entity with characteristic clinicopathological features. Recently, the association between IgG4-related sclerosing disease and the risk of malignancies has been suggested. IgG4-related autoimmune pancreatitis with pancreatic cancer has been reported. Further, a few cases of extraocular malignant lymphoma in patients with IgG4-related sclerosing disease have also been documented. Herein, we describe the first documented case of anaplastic large cell lymphoma (ALCL) following IgG4-related autoimmune pancreatitis and cholecystitis and diffuse large B-cell lymphoma (DLBCL). A 61-year-old Japanese male, with a past history of DLBCL, was detected with swelling of the pancreas and tumorous lesions in the gallbladder. Histopathological study of the resected gallbladder specimen revealed diffuse lymphoplasmacytic infiltration with fibrosclerosis in the entire gallbladder wall. Eosinophilic infiltration and obliterative phlebitis were also noted. Immunohistochemically, many IgG4-positive plasma cells had infiltrated into the lesion, and the ratio of IgG4/IgG-positive plasma cells was 71.6%. Accordingly, a diagnosis of IgG4-related cholecystitis was made. Seven months later, he presented with a painful tumor in his left parotid gland. Histopathological study demonstrated diffuse or cohesive sheet-like proliferation of large-sized lymphoid cells with rich slightly eosinophilic cytoplasm and irregular-shaped large nuclei. These lymphoid cells were positive for CD30, CD4, and cytotoxic markers, but negative for CD3 and ALK. Therefore, a diagnosis of ALK-negative ALCL was made. It has been suggested that the incidence of malignant lymphoma may be high in patients with IgG4-related sclerosing disease, therefore, intense medical follow-up is important in patients with this disorder.