A 39-year-old previously healthy man presented to us with a 15-day history of back pain and a 3-day history of dysuresia, exacerbated by weakness in the lower extremities for 2 days. One day prior to admission, he was unable to walk or urinate. He denied any history of hypertension, diabetes, heart diseases, infectious diseases, or trauma as well as any history of direct contact with cattle or sheep or tuberculosis. On admission, physical examination showed a loss of sensation below the T12 dermatome, spinal tenderness at the T2 level, and muscle strength of grade 3/5 in the bilateral lower extremities. Additionally, there was radicular pain during cervical anteflexion. The muscular tone was normal in all extremities. The proprioceptive sensation in the lower extremities was also decreased, and the abdominal and cremasteric reflexes disappeared. Ankle clonus, Hoffmann sign, Babinski sign, and Chaddock sign were positive for bilateral extremities. On the second day after admission, the lower extremity weakness was exacerbated. Neurological reexamination showed a loss of sensation below the T8 dermatome and a muscle strength of grade 2/5 in the bilateral lower extremities; nevertheless, the bilateral pathological reflexes (Hoffmann sign, Babinski sign, and Chaddock sign) were all negative.
Cervical magnetic resonance imaging (MRI) showed strip-shaped abnormal signals along the anterior and posterior borders of the spinal cord at the C5-T4 levels (Figure 1, upper). Cerebrospinal fluid (CSF) examination via a lumbar puncture showed faint-yellow fluid with a normal pressure of 130 mmH2O. The protein level was elevated (2.7 g/L), and Pandy's test showed strong positivity. Cell counting showed elevated leukocytes (31 x 106/L) and erythrocytes (400 x 106/L) with a lymphocyte ratio of 98% and a monocyte ratio of 7%. The IgG level in the CSF was 718.0 mg/L. The CSF smear and IgG antibody for tuberculosis were negative, and quantitative examination and agglutination test for brucellosis were negative as well.
After admission, methylprednisolone (1,000 mg) was administered intravenously. Considering that the subdural extramedullary lesion might be caused by a hematoma or tuberculosis, methylprednisolone was used for 2 days and then replaced by an antituberculosis therapy. Five days later, the symptoms became aggravated. Cervicothoracic MRI revealed strip-shaped abnormal signals along the anterior and posterior borders of the dural sac at the T1-T6 levels (Figure 1, lower). Physical examination showed a muscle strength of grade 0/5 in the bilateral lower extremities. A diagnosis of spinal cord compression was made, and surgical resection of the space-occupying lesion was scheduled.
Intraoperatively, the lesion showed a rubber-like appearance with a hard nature, and it was distributed extensively on the dura mater. The dura mater had no pulsation with a high tension. After the dura mater was incised, a subdural lesion was noted with a rubber-like appearance as well, and the spinal cord was compressed. The subdural and epidural lesions were resected for decompression. The post-operative course was uneventful. Physical examination showed a loss of sensation below the T4 dermatome, and muscle strength of grade 0/5 in the bilateral lower extremities. The bilateral pathological reflexes (Babinski sign and Chaddock sign) were all positive.
Histopathological examination showed diffuse infiltration of inflammatory cells within the fibrofatty tissue, and numerous plasma cell infiltrates could be noted (Figures 2A,B). Immunohistochemical staining showed that the plasma cells were positive for IgG and IgG4. Focally, more than 10 IgG4-positive plasma cells could be seen per high-power field (HPF) (Figures 2C,D). Additionally, perivascular histiocytosis was arranged in clusters with scattered multinuclear giant cells, which were positive for CD68 but negative for CD1alpha. A diagnosis of IgG4-related sclerosing disease with histiocytosis was made. The Ki-67 labeling index reached 30%.
Further laboratory examination revealed an IgG4 level of 1.050 g/L, an erythrocyte sedimentation rate of 120 mm/1 h, and a C-reactive protein level of 115 mg/L. Based on the clinical and histopathological profiles, a diagnosis of spinal cord compression caused by IgG4-related spinal pachymeningitis was made. Corticosteroid therapy was scheduled (Table 1). Two days following the corticosteroid administration, the muscle strength in the right lower extremity returned to grade 1/5. Methylprednisolone was used for 3 days before the patient was discharged, and he was told to continue small-dose methylprednisolone maintenance therapy. When the patient was discharged, the muscle strength in the left lower extremity had returned to grade 1/5 and that in the right lower extremity had returned to grade 2/5; the sensory functions remained unchanged, and bilateral pathological reflexes (ankle clonus, Hoffmann sign, Babinski sign, and Chaddock sign) remained positive. During the subsequent follow-up period, the patient's condition was stable and the corticosteroid was decreased 4 mg per week.