The patient is a 57 year old Hispanic male with history of AIDS who presented with two weeks of left flank pain, fatigue and fevers. Physical exam showed mild tenderness of the left flank. Labs showed a chronic anemia and an absolute CD4 count of 111. Kidney function was normal, and urinalysis was without evidence of infection, blood or protein. CT abdomen showed a 12.5 cm left renal mass with satellite nodules. There was no splenomegaly. CT head and chest were negative. Initially, renal cell carcinoma (RCC) was suspected but after review with urology it was felt the mass was inconsistent with RCC and the patient underwent biopsy. The pathology initially came back as indeterminate but likely lymphoma. After further studies, the specimen was found to be CD5 positive, cyclin D1 negative, and SOX11 positive. This is consistent with Mantle Cell Lymphoma (MCL).
Discussion:
Many HIV/AIDS patient are afflicted with various Non-Hodgkin’s Lymphomas; MCL is infrequently one of them. One large epidemiologic study quoted the MCL rate in this population at zero. Overall, MCL represents 4-9% of all lymphomas and typically presents with lymphadenopathy, splenomegaly and bone marrow involvement. Systems such as the gastrointestinal tract, skin, and central nervous system can also be affected. MCL can infiltrate the kidney causing renal failure, and cases of glomerulonephritis have been described. This is the first reported case of MCL presenting as a renal mass and only the second case of MCL documented in a patient with HIV/AIDS. Additionally, the pathologic diagnosis of MCL in this patient was unusual. MCL can be genetically identified by a translocation that activates expression of cyclin D1. This is used as a diagnostic marker and is positive in up to 98% of cases. However, it is recognized that there is a subset of MCL that is morphologically and genetically similar with exception of the absence of cyclin D1 expression. SOX11 has been identified as a highly specific marker to identify this subset. Prior to this finding, cyclin D1- negative specimens were difficult to distinguish from other small B-cell lymphomas.
Conclusions:
The hospitalist must keep a broad differential when a patient presents with a renal mass and imaging review with radiology or urology should always be sought to ensure proper diagnosis and consultation. We must also be aware that as the HIV/AIDS population ages and diagnostic accuracy improves, MCL may become a more common diagnosis in all patient populations.