Isolated perinephric lymphoma: A distinct presentation of primary lymphoma

Isolated perinephric lymphoma is a rare presentation of primary lymphoma. We report a case of a 77-year-old male who was incidentally found to have isolated left perinephric lymphoma. We outline the diagnostic work up and subsequent diagnosis of lymphoma as well as the considerations that guided management. Ultimately, bone marrow biopsy and PET-CT were used as diagnostic tools to assess for systemic disease and the patient was managed with observation and interval follow-up imaging.