IgG4-related disease is a newly recognized fibroinflammatory disorder that has the ability to affect nearly every organ system. It is characterized by tumefactive lesions and
fibrosis and closely mimics
neoplasms. Only one case of IgG4-related bladder mass has been reported in the literature, but there are no reports of
IgG4-related disease in a urachal mass. Herein, we report a 26-year-old male who initially presented with symptoms of recurrent UTI. Work-up revealed a 6 cm urachal
tumor, a 1.4 cm pulmonary lesion, and mediastinal
lymphadenopathy; all metabolically active on PET scan and suspicious for
urachal adenocarcinoma. Lung lesion fine needle aspiration and TURBT pathology revealed
inflammation but no evidence of
malignancy. The patient underwent a
partial cystectomy and umbilectomy with pathology demonstrating dense plasmacytic cells, a high rate of immunohistochemistry staining positive for
IgG4 plasma cells, a storiform pattern of
fibrosis, and an obliterative
phlebitis. Furthermore, the patient had an elevated serum
IgG4 level of 227 mg/dL (range 2.4-121 mg/dL).
IgG4-related disease is a newly recognized fibroinflammatory disorder that can mimic
neoplastic processes and a high index of suspicion and accurate tissue pathology is necessary for an accurate diagnosis.