International Journal of Hematology | 2019
Neurolymphomatosis of the sciatic and tibial nerves as an initial presentation of lung diffuse large B cell lymphoma detected by positron emission tomography/computed tomography
Abstract
A 77-year-old Japanese female was referred with abnormal chest X-ray findings during her annual medical check-up. She had no respiratory symptoms, but had a tingling sensation in her left leg. Neurological examination results were consistent with sciatic and tibial neuropathy. On admission, laboratory findings showed slight elevation of serum lactate dehydrogenase (235 U/L; normal, 119–229 U/L) and soluble interleukin-2 receptor (914 U/mL; normal, 122–499 U/ mL) levels. Chest computed tomography showed a nodular lesion in the left lung; 18-F fludeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) imaging showed increased metabolism in the lung lesion (SUV max: 15.79), left sciatic nerve, and left tibial nerve (SUV max: 11.54) (Fig. 1a, b). Contrast-enhanced magnetic resonance imaging showed normal findings, with the exception of diffuse enlargement with enhancement of the left sciatic nerve and left tibial nerve on T1-weighted images. Transbronchial lung biopsy revealed a diffuse large B cell lymphoma that positively expressed CD20, bcl-2, bcl-6, and MUM-1, and was negative for CD5 and CD10 (Fig. 2a, b). Examination of cerebrospinal fluid revealed unremarkable findings. Due to the risk of irreversible neurological deficits, we did not perform nerve biopsy of the sciatic or tibial nerves. On biopsy of the left sural nerve, no pathological infiltration of lymphoma cells was detected. Although no invasion of the nerve by lymphoma cells was confirmed, a diagnosis of neurolymphomatosis of the sciatic and tibial nerves with pulmonary diffuse large B cell lymphoma nonetheless appeared highly probable. A rituximab, cyclophosphamide, hydroxydoxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy regimen and concurrent local radiotherapy to the left sciatic and tibial nerves (30 Gy) were administered. After the first cycle of chemotherapy, the increased FDG uptake in the lung lesion, left sciatic nerve, and left tibial nerve on 18F-FDG-PET/CT disappeared completely (Fig. 3). The patient is being treated with additional * Kentaro Narita [email protected]