18F‐Fluorodeoxyglucose positron emission tomography for evaluation of intravascular large B‐cell lymphoma

Abstract

A 73-year-old woman was referred to our hospital with a 1month history of recurrent fever, worsening mental state and general weakness. Physical examination showed confusion and mild splenomegaly but no peripheral lymphadenopathy or skin lesions. Her serum lactate dehydrogenase (LDH) and soluble interleukin-2 receptor were elevated to 1110 iu/l and 14 400 U/ml respectively. Computed tomography of the abdomen revealed mild hepatosplenomegaly and a right adrenal mass (top left panel). A bone marrow aspirate from the sternum showed scattered large atypical lymphoid cells (4AE2%) suggesting lymphoma infiltration. Based on our prior experience with intravascular lymphoma (IVL), we performed random skin biopsies from normal appearing skin on the trunk, thigh and upper arms. All specimens showed large lymphoid cells with irregular nuclei filling the small vessels in subcutaneous tissues (middle left panel). These cells were stained positively with CD20 (bottom left panel) and negatively with CD3 monoclonal antibody. A diagnosis of IVL of B-cell origin was made. F-Fluorodeoxyglucose positron emission tomography (F-FDG PET) was performed before treatment. In addition to intense uptake of the adrenal mass, increased F-FDG uptake was observed in the vertebrae, humeri, ulnae, radii and iliac crests (top right panels). After rituximab infusion (375 mg/m), her general condition and mental status improved rapidly. The serum LDH level was elevated transiently but returned to within normal limits over the next few days. After two courses of weekly rituximab and one course of cyclophosphamide, doxorubicin, vincristine and prednisolone (CHOP) chemotherapy, F-FDG PET (bottom right panels) scan was repeated, and no abnormal F-FDG uptake was observed. The patient entered complete remission and continued to receive additional treatment with rituximab and CHOP. IVL is a very rare subtype of non-Hodgkin lymphoma with an aggressive natural course. F-FDG PET scanning appears to be extremely useful for evaluating the early response to the chemotherapy in patients with IVL.