He was treated empirically with 5 gr of IV methylprednisolone followed by 50 mg daily oral prednisolone for two weeks.

The histopathological assessment of peroneal nerve biopsy revealed intravascular proliferation of large atypical lymphocytes. The cells were positive for CD-20 on IHC staining (figure 1). Further IHC specification was not feasible due to the few number of available cells.

The final diagnosis was intravascular large B-cell lymphoma, presenting as mono-neuritis multiplex. The patient was referred to an oncology clinic where he received chemotherapy with a combination of doxorubicin, rituximab, cyclophosphamide, and vincristine for about 6 months. Along with chemotherapy, the patient continued receiving oral prednisolone at a dose of 100 mg per day.

We visited the patient for follow-up 4 months after he completed his first cycle of chemotherapy. His weakness had subjectively improved and his Overall Neuropathy Limitations Scale (ONLS) had improved from 1 to 0 in arms and from 4 to 2 in legs.

However follow-up electrodiagnostic studies showed progression in axonal loss and worsening of polyneuropathy. We postulate that the reason was disease progression and chemotherapy-induced axonal damage.

He came back to the clinic after 2 years of his first symptoms complaining of worsening weakness; his ONLS had improved to 2 in arms and 3 in legs. We performed a head-to-toe examination and found new skin lesions in his abdomen (Figure 2 ); The skin lesion was biopsied and the histopathologic study confirmed the recurrence of intravascular Large-B-cell lymphoma. The timeline in figure 3 summarizes the disease course in our patient.