Concurrent renal cell carcinoma and hematologic malignancies: Nine case reports

BACKGROUND: The presence of renal cell carcinoma (RCC) and hematologic malignancies (HM) in the same patient is rarely observed. Three primary findings have been described in these patients, including male gender and lymphoid malignancy predominance, and the HM are usually diagnosed before or simultaneously with the RCC. There is a lack of evidence about clinical outcomes in this setting. We report the common characteristics of 9 patients diagnosed with concurrent RCC and HM and their clinical course and response to treatment. CASE SUMMARY: Four (44%) patients were diagnosed with RCC prior to the HM, the diagnosis was simultaneous in 4 (44%) patients, and 1 (11%) patient was diagnosed with the HM prior to the RCC. No patients were treated with cytotoxic chemotherapy or radiation between the diagnosis of RCC and HM. Several unique features were seen in our case series, such as 3 simultaneous cancers in 1 (11%) patient, a splenectomy leading to remission of diffuse large B cell lymphoma without the use of chemotherapy in 1 (11%) patient, chemotherapy and rituximab for lymphoma resulting in a complete response in primary RCC in 1 (11%) patient, and immunotherapy providing an excellent response for primary renal leiomyosarcoma in 1 (11%) patient. CONCLUSION: These findings highlight the potential role of immune system dysregulation in patients with the diagnosis of RCC and HM whereby the first malignancy predisposes to the second through an immunomodulatory effect. HM have the potential of being confused with lymph node metastasis from kidney cancer. Lymph node biopsy may be necessary at the time of initial diagnosis or in cases of mixed response to therapy. Long-term medical surveillance is warranted when a patient is diagnosed with RCC or HM. Clinicians should be aware of the higher prevalence of male gender and lymphoid malignancy with concurrent RCC and HM and that either of these conditions may be diagnosed first or they may be diagnosed simultaneously.