[Intravascular large B cell lymphoma pathological findings led by positron emission tomography findings: About one case].

Intravascular large B cell lymphoma is a rare non-Hodgkin large B cell lymphoma disease, with heterogeneous clinical manifestation and difficult pathological diagnosis. Positron emission tomography may be helpfull in this context and has already been reported. A 45-year-old woman was admitted for persistent high fever, inflammatory syndrome and unexplained haemophagocytic syndrome. Bilateral cortical renal hypermetabolism at positron emission tomography initially misled to pyelonephritis diagnosis and secondarily led to kidney biopsy, which showed intravascular large B cell lymphoma. Renal involvement in intravascular large B cell lymphoma is rare and is usually characterized by acute renal failure and proteinuria. Global hypermetabolism at positron emission tomography has already been described in this context, but cortical hypermetabolism has never been associated with pathological findings. In front of persistent high fever without etiology, this positron emission tomography feature must lead to intravascular large B cell lymphoma suspicion and to kidney biopsy to obtain pathological proof.