Methotrexate-associated lymphoproliferative disorder of the thoracic spine in a patient with rheumatoid arthritis receiving methotrexate: a case report

The first case of methotrexate-associated lymphoproliferative disorder in the sacrum: a case report

Methotrexate (MTX) is a drug used for treating rheumatoid arthritis. Recently, the reported incidence of methotrexate-associated lymphoproliferative disease (MTX-LPD) has increased, especially in Japan. Extranodal involvement is observed in half of MTX-LPD cases. However, only a few spinal lesions have been reported, with none in the sacrum. Additionally, Epstein-Barr virus (EBV) infection has also been implicated in the pathogenesis of MTX-LPD. Herein, we describe the case of a 74-year-old woman with MTX-LPD in the sacral spine who complained of severe back pain and nocturnal pain. Radiographs revealed a tumour on the right wing of the sacrum and a positive EBV immunoglobulin G antibody titre. MTX-LPD was suspected based on imaging findings and a history of MTX administration. A pathological examination was performed on the CT-guided biopsy specimen. The histopathological diagnosis was MTX-LPD, and MTX was discontinued. Three months after MTX administration ended, the tumour tended to shrink, and 1 year later, significant tumour shrinkage was observed. This experience suggests that MTX-LPD can be treated by discontinuing MTX administration. Therefore, early and accurate diagnosis is required, as is avoiding unnecessary treatment such as surgery. MTX-LPD should be considered, especially in spinal origin tumours in EBV-infected patients on MTX.

Pathological Vertebral Fracture Arising From Methotrexate-Associated Lymphoproliferative Disorder in a Patient With Systemic Lupus Erythematosus

The incidence of lymphoproliferative disorders associated with methotrexate is rising in patients with rheumatoid arthritis. These disorders typically exhibit spontaneous tumor regression upon discontinuation of methotrexate therapy. Spinal lesions associated with these diseases are extremely rare. We present a case of systemic lupus erythematosus in which the patient developed lumbar spine lymphoproliferative disorders secondary to methotrexate therapy, which failed to regress despite discontinuation of the drug, ultimately leading to pathological fracture necessitating posterior spinal fixation. A 60-year-old woman had been diagnosed with systemic lupus erythematosus at the age of 55 years and had been taking prednisolone, hydroxychloroquine, and methotrexate. Throughout the course of her treatment, she experienced recurrent tumefaction and lymph node swelling in various locations. These masses and lymphadenopathy were believed to be potential complications of methotrexate-associated lymphoproliferative disorders, leading to the discontinuation of methotrexate. One month prior to cessation of methotrexate therapy, the patient presented to an orthopedic clinic with lower back pain, and T2-weighted magnetic resonance imaging revealed low signal intensity in the Th10 and L2 vertebrae, initially misdiagnosed as lumbar spinal stenosis. The patient was eventually referred to our department under suspicion of malignant pathology. Computed tomography identified a vertical fracture of the L2 vertebra, which, in conjunction with the imaging results, led to the diagnosis of pathological fracture secondary to methotrexate-associated lymphoproliferative disorder. Following admission to our department, bone biopsy and percutaneous pedicle screw fixation were performed one week later. Pathological examination confirmed the diagnosis of methotrexate-associated lymphoproliferative disorder. Given the possibility of pathological fracture in patients on methotrexate therapy experiencing severe back pain, additional imaging studies should be considered.

Methotrexate-Associated Lymphoproliferative Disease of the Thoracic Spine Misdiagnosed as Metastatic Spinal Tumor: A Case Report

Methotrexate (MTX) is increasingly used in the treatment of rheumatoid arthritis. Many recent reports have identified MTX-related lymphoproliferative disorder (MTX-LPD) as lymphoma that develops during MTX therapy. However, spinal lesions, which are extremely rare, can be misdiagnosed as spinal metastases or pyogenic spondylitis. Here, we describe a 69-year-old man with rheumatoid arthritis who had MTX-LPD of the thoracic spine. He complained of back pain and weakness in the bilateral iliopsoas muscle. A radiographical assessment by his previous physician revealed the cause to be a spinal tumor. They performed posterior spinal decompression and fixation, and a pathological examination revealed only inflammatory changes, necrosis, and increased collagen fiber growth, with no evidence of malignancy. Nevertheless, magnetic resonance imaging two weeks after the surgery showed an increase in the size of the spinal tumor. When the lesion paralyzed the patient soon afterward, the physician considered that a total en bloc spondylectomy was necessary and referred the patient to our hospital. MTX-LPD was suspected because of a history of MTX administration, and a biopsy, posterior spinal decompression, and fixation were performed again. Following the histopathological diagnosis of the tumor as MTX-LPD, MTX administration was terminated. Three months following surgery, the tumors' removal was confirmed. Because MTX-LPD can be treated with MTX withdrawal, correct diagnoses should be made, and unnecessary treatments avoided.