Early diagnosis of recurrent diffuse large B‐cell lymphoma showing intravascular lymphoma by random skin biopsy

A 66‐year‐old man was admitted to our hospital presenting 2 weeks’ history of fever of unknown origin with elevated levels of lactate dehydrogenase and C‐reactive protein. Six years before this episode, he had developed diffuse large B‐cell lymphoma, which had been successfully treated with chemoradiation. While recurrence of diffuse large B‐cell lymphoma was suspected, there was neither lymphadenopathy nor tumor formation by the imaging study. Random biopsy from normal‐appearing abdominal skin showed extensive infiltration of CD20+, CD79a+, CD3− atypical lymphoid cells in the lumen of vessels in subcutaneous tissues. These findings led us to the diagnosis of intravascular B‐cell lymphoma. Following rituximab plus cyclophosphamide, adriamycin, vincristine and prednisolone therapy, high fever subsided, and lactate dehydrogenase and C‐reactive protein levels returned to the normal range. In conclusion, random skin biopsy is useful for the early diagnosis of intravascular B‐cell lymphoma.