First Report of IgG4 Related Disease Primary Presenting as Vertebral Bone Marrow Lesions

Abstract

IgG4-related disease is a fibro-inflammatory disorder characterized by swelling of tissues and affected organs accompanied by the development of scar tissue (fibrosis) and infiltration by IgG4 positive plasma cells. Almost any organ can be affected, including, but rarely, bone marrowinvolvement. Here we present a case of a 76-year-old male with IgG4-related disease presenting primarily with vertebral bone marrow lesions. Histopathology showed the typical features of storiform fibrosis, and increased IgG4 positive plasma cells. Treatment with corticosteroids significantly improved wellbeing and resolved lesion size on MRI.

Keywords: IgG4-related disease; MRI; bone marrow; histology; immunhistochemistry; plasma cell; spine; vertebra.

Figure 1

Vertebral lesions at baseline and during follow-up. (A) Total spine sagittal reconstructions of T1-weighted turbo spin-echo (TSE; left 2 panels), contrast-enhanced water-selective T1-weighted TSE (middle two panels) and T2-weighted sequences (right two panel) at baseline (t = 0) and 10 months (t = 10 mos) after initiation of treatment. At baseline, note the mottled appearance and lower signal intensity of the vertebral bodies on the T1-weighted sequences at baseline. At 10 months after treatment the signal intensity has returned to near normal signal intensity. (B) Zoomed detail of T2-weighted sequences at baseline (left) and 10 months after treatment (right) of the cervical spine. The area outlined by the dashed area at baseline signifies abnormally high signal intensity of the vertebral bone marrow, which returned to normal values at 10 months after treatment.

Figure 2

Microscopic examination of the lumbar vertebra (biopsy). (A) On overview, the marrow in between the bony trabeculae shows a quite sharp demarcation between normal bone marrow (one third on the left) and the fibrotic lesion (two thirds on the right) (H&E staining, 79x magnification). (B) Higher magnification of the lesion shows fibrosis rich in fibroblasts and arranged in a somewhat storiform fashion with admixed plasma cells and lymphocytes (H&E staining, 400x magnification). (C) Highest magnification shows several fibroblast (arrows), plasma cells (encircled) and lymphocytes (arrow heads) (H&E staining, 800x magnification). (D) Immunohistochemistry for CD138 shows in dark brown the numerous plasma cells (CD138 immunohistochemical staining, 400x magnification). (E,F) Immunohistochemistry for IgG (E) and IgG4 (F) shows in dark brown numerous IgG and IgG4 positive plasma cells, respectively, some of which encircled in red (IgG and IgG4 immunohistochemical stainings, 200x magnification).