Tohoku J. Exp. Med., 2023 August, 260(4)

Primary Malignant Lymphoma of the Cauda Equina Diagnosed after Decompression for Lumbar Spinal Stenosis: A Case Report

Manabu Suzuki,¹,² Kohei Takahashi,¹ Mika Watanabe,³ Ko Hashimoto,¹ Takahiro Onoki,¹ Kyoichi Handa⁴ and Toshimi Aizawa¹

¹Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
²Department of Orthopaedic Surgery, National Hospital Organization Sendai Nishitaga Hospital, Sendai, Miyagi, Japan
³Department of Pathology, KKR Tohoku Kosai Hospital, Sendai, Miyagi Japan
⁴Department of Orthopaedic Surgery, Takeda General Hospital, Aizu-Wakamatsu, Fukushima, Japan

Primary malignant lymphoma confinement to the cauda equina is rare. Only 14 cases of primary malignant lymphoma in the cauda equina have been reported. In these cases, the clinical features were similar to those of lumbar spinal canal stenosis (LSCS). This report describes a case of diffuse large B-cell lymphoma of the cauda equina that was diagnosed after decompression surgery for LSCS. An 80-year-old man presented with gait disturbance due to progressive muscle weakness in the lower extremities over the previous two months. He was diagnosed with LSCS, and decompression surgery was performed. However, the muscle weakness worsened after surgery; therefore, he was referred to our department. Plain magnetic resonance imaging (MRI) revealed swelling of the cauda equina. It demonstrated marked homogenous enhancement by gadolinium-diethylenetriamine pentaacetic acid. ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) revealed diffuse accumulation of ¹⁸F-FDG in the cauda equina. These imaging findings were consistent with those of cauda equina lymphomas. To confirm the diagnosis, we performed an open biopsy of the cauda equina. Histological examination indicated diffuse large B-cell lymphoma. Considering the patient's age and activities of daily living, further treatment was not performed. The patient died four months after the first surgery. Rapid progression of muscle weakness, which cannot be prevented by decompression surgery, and swollen cauda equina on MRI may be signs of this disorder. Gadolinium-enhanced MRI, ¹⁸F-FDG PET, and histological investigation of the cauda equina should be performed for diagnosing primary malignant lymphoma of the cauda equina.

Key words —— ¹⁸F-FDG PET; cauda equina; Gd-DTPA; malignant lymphoma; open biopsy

© 2023 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2023 August, 260(4), 341-346.

Correspondence: Manabu Suzuki, Department of Orthopaedic Surgery, National Hospital Organization Sendai Nishitaga Hospital, 2-11-11 Kagitori-honcho, Taihaku-ku, Sendai, Miyagi 982-8555, Japan.

e-mail: manabu1029@hotmail.com