A case of IgG4-related disease manifesting as a spinal epidural mass

Abstract

IgG4-related disease is an immune-mediated fibroinflammatory condition. Isolated manifestation in the spine as hypertrophic pachymeningitis is very rare and the mass-like lesion on MRI often mimic tumour or infection. Patients would present with symptoms that result from mass effect or neurovascular compression. Studies showed that serum and CSF IgG4 levels are rarely informative, and therefore, tissue biopsy is crucial for accurate diagnosis. Apart from supporting the diagnosis, MRI is helpful in delineating the extent of disease and follow-up after treatment. A 18F-FDG PET/CT scan is useful in detecting systemic manifestations of IgG4-related disease. Although IgG4-related disease generally responds well to corticosteroid at inflammatory state, relapse is not uncommon. Current treatment strategies for IgG4-related hypertrophic pachymeningitis are high dose corticosteroid therapy and early decompressive surgery to avoid chronic neurological complications. We described a case of a 27-year-old gentleman complaining of lower limb weakness and numbness. MRI showed a mass-like epidural lesion at the thoracic spine causing cord compression. Open biopsy of the epidural mass demonstrated histopathological characteristics of IgG4-related disease. Patient responded well to early surgical decompression of the spinal cord and corticosteroid as evidenced by symptom improvement and resolving mass on subsequent MRI study. However, a follow-up MRI revealed disease recurrence years later.

Keywords: IgG4; IgG4-related disease; IgG4-related hypertrophic pachymeningitis; MRI; epidural mass; hypertrophic pachymeningitis.

Figure 1.

Sagittal T1 weighted (A), T2 STIR (B), and T1 weighted post-contrast (C) MRI images of upper thoracic spine demonstrated an enhancing infiltrative anterior epidural mass at T2 to T4 levels (white arrows) causing mild cord compression mainly at T3 level with cord oedema. Axial T2 STIR (D) and T1 weighted post-contrast (E) at T3 level showed that the epidural mass infiltrates into bilateral T3 lateral recesses and bilateral T3/4 intervertebral foramina (black asterisks). Enhancing lesions were also noted at the posterior aspect of T2 to T4 vertebral bodies (E).

Figure 2.

(A-F) F-18 FDG PET-CT showed an intraspinal mass at T3 level with increased FDG uptake (SUV max 4.2). No overt bone erosion or extraspinal hypermetabolic lesion was detected.

Figure 3.

Histopathological findings in the epidural lesion. The lesion consists of fibrotic tissue with lymphoplasmacytic infiltrate between lamellated collagen fibres. The inflammatory cells comprise a mixture of B and T lymphocytes, plasma cells and macrophages. The plasma cells were mostly positive for IgG4, with an IgG4: IgG ratio >90%. Pathological diagnosis was IgG4-related fibro-inflammatory lesion.

Figure 4.

Follow up MRI 3 months after clinical recurrence upon low dose corticosteroid for a few years. Sagittal T1 weighted (A), T2 STIR (B), and T1 weighted post-contrast (C) MRI images of upper thoracic spine demonstrated a new enhancing infiltrative posterior epidural mass at C7 to T4 levels (white arrows) causing mild cord compression mainly at T2 level with cord edema. Axial T2 stir (D) and T1 weighted post-contrast (E) at T2 level showed that the epidural mass infiltrates into bilateral T2 lateral recesses and bilateral T2/3 intervertebral foramina (black asterisks). A new enhancing lesion was also noted at the posterior aspect of T2 vertebral body with overlying thin anterior epidural thickening (C, E). Mild residue T2 STIR hyperintense signal intensity (B) in the spinal cord at T3 level was compatible with old insult.