{'fraction_non_alphanumeric': 0.028238918363854185, 'fraction_numerical': 0.016258771179188773, 'mean_word_length': 5.151578947368421, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Primary spinal epidural diffuse large B-cell lymphoma with paraplegia as the first manifestation: a case report

Abstract Primary spinal epidural diffuse large B-cell lymphoma (DLBCL) is rare and often easily misdiagnose. Here, we presented a case of primary spinal epidural DLBCL with paraplegia as the first manifestation. He was misdiagnosed as thoracic disc herniation and thoracic tuberculosis successively. DLBCL was confirmed after surgery ultimately. After 6 cycles of chemotherapy with R-CHOPE, the patient went back to normal life without relapse during 2-year follow-up. Primary spinal epidural lymphoma should be suspected in patients with spinal cord compression with imaging showing isointense, homogeneous extradural contiguous level compressive soft‑tissue lesion without bony involvement and previous history of cancer.


Introduction
Primary spinal epidural lymphoma (PSEL) is an entity of lymphomas located in epidural without any other recognizable sites of lymphomas at diagnosis. 1 An epidural location for lymphoma is observed in 0.1-6.5% of all the lymphomas; 1 thus, it is challenging at diagnosis and may easily be misdiagnosed. Here, we presented a case of primary spinal epidural DLBCL with paraplegia as the first manifestation.

Case presentation
A 39-year-old man was admitted to our hospital on December 23, 2015, with back pain, numbness and weakness of lower limbs for 2 months. Thoracic disc herniation was considered in local hospital 2 months ago; however, conservative treatment did not work. Moreover, the disease quickly progressed to paraplegia on December 24, 2015. The neurologic examination demonstrated a minor motor impairment of lower limbs and reflexes were hyperactive. Anal sphincter tone was without damage, negative Hoffman, Trömner and Babinski's sign. He presented a sensory level of hypoesthesia and loss of thermalgesia at T7. T-SPOT.TB was positive. The enhanced magnetic resonance imaging (MRI) of thoracic vertebra on December 24, 2015 (Figure 1), suggested that thoracic 7 vertebral body, the thoracic 7 and 8 vertebral body accessory tuberculosis was considered, accompanied by intraspinal abscess formation. He was misdiagnosed with thoracic tuberculosis. Posterior pedicle screw fixation + spinal canal decompression + lesion clearance + bone grafting and fusion was performed on December 25, 2015. Surgical pathology suggested DLBCL. The immunohistochemical ( Figure 2)   Ethical approval was not necessary for the case report. The patient has consented for the publication of the present case report.

Discussion
In this case, the patient was misdiagnosed as thoracic disc herniation and thoracic tuberculosis successively (Figure 4). In the previous reported study, 2 the overall specificity and sensitivity of the T-SPOT.TB were 92.83% and 83.67%, respectively. Patients with cured tuberculosis tended to induce false-positive results. In this case, T-SPOT.TB was false-positive.
PSEL usually occurs in 40-50 years old, and the malefemale ratio is 1.6:1. The 3-year overall survival was 81.1%, and disease-free survival rate was 46.3%. 3 The origin of PSEL is thought to be derived from lymphatic tissue along the venous plexus in the epidural space or the paravertebral lymphoid rests or the vertebral body, which later extends to the epidural space. 4 The most common presenting symptoms reported included lower limb weakness, localized back pain, and bladder dysfunction. The symptoms and signs of the disease depend on the location and size of the tumor. The onset is usually subacute, ranging from days to weeks. The clinical symptoms are divided into two stages: the first stage is the prodromal stage, which is characterized by localized back pain and incidental radicular pain, which lasts from several months to 1 year; the second stage is the progressive stage, which is characterized by rapid neurological decline due to nerve compression and lasts for 2 to 8 weeks. There were some published case reports about primary spinal epidural DLBCL (Table 1). [5][6][7] For patients with high suspicion of PSEL, MRI is helpful for diagnosis. MRI plain scan usually showed T1W1 signal or low signal, T2WI signal or high signal, but some literature reported that T2WI showed low signal, may be related to the relative density of tumor cells. Hyperintense T2 signal greater than that of adjacent fat with adjacent expansile bone disease differentiates epidural metastases from lymphoma. 8 Primary spinal epidural non-Hodgkin's lymphoma (NHL) accounts for less than 1% of all NHL. 5 Most epidural lymphomas are moderately and well-differentiated B-cell lymphoma. DLBCL is the most common type, accounting for 1.8% of all DLBCL. Pathological examination revealed atypical lymphocyte proliferation, and immunohistochemistry showed positive cluster of differentiation (CD)20, negative leukocyte common antigen and CD138, CD30 and CD3. The specific management has not been established yet. Surgery is the mainstay of treatment for cord decompression with aggressive chemotherapy in conjunction with radiotherapy is associated with good functional outcome. 9 It is not known whether preventive intrathecal injection is necessary. In this case, the patient refused to take preventive intrathecal injection.
All in all, PSEL should be suspected in patients with spinal cord compression with imaging showing isointense, homogeneous extradural contiguous level compressive soft-tissue lesion without bony involvement and previous history of cancer.

Ethics approval and consent to participate
The patient consent for publication of the case report was written informed consent and all identifying information was removed. No other ethical parameters beyond privacy were affected as this was not a clinical trial. Thoracic disc herniation was considered Figure 4 The process of therapy.