Primary renal non-Hodgkin's lymphoma: A narrative review of literature.

Renal involvement by Non-Hodgkin's lymphoma (NHL) is very rare, and involvement of the kidney as the primary site of NHL (PRNHL) is much more uncommon. Gold standard for the diagnosis of PRNHL is histology and imaging modalities although helpful are not specific. Nephrectomy has been mostly recommended for low grade lymphomas, and for high grade PRNHLs, chemotherapy without nephrectomy has been recommended as the treatment of choice. This tumor is aggressive with poor prognosis. This poor prognosis is partly because of delayed diagnosis and partly because of unnecessary surgeries, so it should be kept in mind, especially in bilateral renal tumors with unusual imaging characteristics, to take a tissue biopsy before nephrectomy. In this review, we will discuss all the detailed aspects of clinical, pathologic, and imaging characteristics of 83 cases of PRNHL reported in the last 20 years in the English literature so far. For this purpose, all the published cases of the primary non-Hodgkin's lymphoma of kidney were reviewed via a search in PubMed, Scopus, and Google Scholar, (1999-2019), using the keywords of "Primary renal lymphoma" and "Non-Hodgkin's lymphoma and kidney," "renal Non-Hodgkin's lymphoma," "renal lymphoma," and "lymphoma and kidney." There were 83 cases in the published English literature which were reviewed for this article. There was some missing information in some cases which has been recorded as "not reported."