A 50-year-old African American male with a past medical history of hypertension, gout, sleep apnea, and hypothyroidism was evaluated for abdominal pain, associated with unintentional 20-pound weight loss, nausea, and vomiting. He denied fever, chills, night sweats, headaches, dyspnea, skin rash, arthralgias, oral ulcers, Raynaud's phenomenon, or chest pain.
On physical exam, he was found to have bilateral parotid and submandibular gland enlargement and right eye proptosis. The patient disclosed that his brother has retroperitoneal fibrosis secondary to IgG4-RD. The initial abdominal computed tomography (CT) revealed a duodenal mass. Endoscopic retrograde cholangiopancreatography (ERCP) showed a mildly dilated common bile duct, not associated with mass or stricture. A biopsy of the intra- and infra-ampullary area demonstrated active chronic duodenitis without evidence of malignancy.
A CT of the thorax showed a confluence of elongated anterior and right paravertebral soft tissue from the midthoracic region to the diaphragmatic level, associated with mildly enlarged thoracic lymph nodes, borderline ascending aortic aneurysm, and scattered small lung nodules (Figure 1).
Complete blood count and biochemical profile were remarkable for chronic anemia and hypoalbuminemia, with normal renal and hepatic function. Monoclonal protein evaluation showed elevated IgG level of 5410 mg/dL (normal: 700-1600 mg/dL), and bone marrow biopsy demonstrated plasma cell dyscrasia (plasma cell count of 6%) with no evidence of lymphoproliferative disorder. Additional laboratory results revealed positive antinuclear antibody (ANA), low complement levels, elevated total IgG and IgG4 subclass, and elevated sedimentation rate (Table 1). The QuantiFERON -TB Gold test was negative.
He underwent excision of a submandibular gland, and the pathology revealed chronic sclerosing sialadenitis, with a large subset of inflammatory cells positively staining for IgG4 (Figure 2).
Subsequently, video-assisted thoracoscopy (VATS) was performed. During the procedure, a multilobar paraspinal mass near the diaphragm was noted, with pathology showing dense fibrosclerosis with increased lymphocytic infiltrates. Although staining for IgG and IgG4 was limited by the level of background staining and areas of crush artifact within the tissue, there was an increase of IgG4 plasma cells (Figure 3).
A follow-up chest CT revealed a prominent paravertebral mass. In view of this finding, the patient was started on prednisone 40 mg daily. While on prednisone, he significantly improved. A subsequent CT done 5 months later showed a decrease in the paraspinal mass (Figure 1). The serum IgG4 level also decreased significantly with prednisone treatment (Table 2). Unfortunately, after prednisone was discontinued, the IgG4 level increased, and there was slight progression in thickness of the paravertebral soft tissue.
Prednisone was restarted, and rituximab therapy was planned.