Porche, Ken

BACKGROUND Neurolymphomatosis (NL), characterized by lymphoma infiltration of peripheral nerves, can be diagnostically challenging because of nonspecific clinical presentations and imaging findings. Tumefactive NL refers to circumferential subparaneurial tumor deposition beneath the paraneurium, outside the epineurium, producing an “encased” nerve appearance on MRI and at surgery. OBSERVATIONS A 76‑year‑old man with treated large B‑cell lymphoma developed a painful left lower trunk brachial plexopathy with numbness of the ring and little fingers and progressive weakness in finger flexors and intrinsic hand muscles. Serial brachial plexus MRI and 18F-fluorodeoxyglucose positron emission tomography over 4 months demonstrated evolution from a thin, circumferential subparaneurial rim of enhancement with mild nerve enlargement to a homogeneously enhancing, tumefactive lesion of the C8 nerve root and lower trunk. Targeted fascicular biopsy of a nonfunctioning C8 fascicle confirmed recurrent B‑cell lymphoma. LESSONS This case illustrates temporal evolution along the tumefactive NL spectrum, from early, subtle subparaneurial involvement to a frankly tumefactive lesion. Recognizing this early MRI pattern, particularly in patients with a history of lymphoma and focal plexopathy, can guide targeted biopsy and facilitate earlier diagnosis and treatment. The clinicoradiological findings suggest that subtle peripheral/subparaneurial enhancement may precede overt tumefactive enlargement. https://thejns.org/doi/10.3171/CASE26139

BACKGROUND Peripheral nerve injuries in the lower extremities impose significant functional and quality-of-life challenges. Loss of plantar flexion is a major deficit. Novel nerve transfers are being introduced to restore function. A novel nerve transfer—partial superficial peroneal to a gastrocnemius branch of the tibial nerve—aimed at restoring plantar flexion is presented in a patient with an incomplete proximal thigh-level sciatic nerve injury. OBSERVATIONS The case of a 27-year-old policeman with a right sciatic nerve injury from a gunshot wound sustained 11 months earlier, characterized by intact dorsiflexion and eversion but with complete loss of plantar flexion and inversion, is presented. The patient underwent a nerve transfer from the superficial peroneal nerve to the lateral gastrocnemius branch of the tibial nerve at 10 months postinjury. At the 2-year follow-up, the patient achieved M4 strength in plantar flexion while maintaining M5 strength in ankle eversion, dorsiflexion, and toe extension, with ongoing signs of reinnervation to the lateral gastrocnemius on electromyography. LESSONS Partial transfer of the superficial peroneal nerve to the lateral gastrocnemius branch of the tibial nerve offers a promising solution for restoring plantar flexion in partial sciatic nerve injuries affecting the tibial division. Tailored distal nerve transfers can enhance recovery, underscoring the importance of surgical innovation in treating complex peripheral nerve injuries. https://thejns.org/doi/10.3171/CASE24888