COEXISTENCE OF MULTIPLE MYELOMA AND CLEAR CELL RENAL CELL CARCINOMA: A CASE SERIES AND REVIEW OF LITERATURE

Introduction:

Renal cell carcinoma (RCC) and multiple myeloma (MM) represent distinct malignancies with disparate origins and clinical presentations, yet emerging evidence suggests a potential association between them, evidenced by a higher-than-expected co-occurrence rate. Warren and Gates had pioneered the concept of "multiple primary malignancies". They defined this situation if a patient had 2 distinct tumours where the possibility of one being a metastasis of the other had been excluded.Shared genetic predispositions, immune dysregulation, paraneoplastic syndromes and cytokine-mediated mechanisms, particularly involving interleukin-6 (IL-6) from RCC cells, and treatment-related factors, such as chemotherapy-induced genomic instability may contribute to MM development or progression. The presence of lytic lesions in a patient with prior RCC may simulate bone metastasis, thus leading to a diagnostic pitfall with potentially adverse clinical implications 

Methods:

It is an observational case report of two patients with renal cell carcinoma and multiple myeloma detected in the same patient.

Results:

Here we describe two patients, a 52 year old female and 66 year old male who were incidentally found to have RCC-MM coexistence who were subsequently treated. In our two reported cases, the discovery of the neoplasia’s was synchronous, which rules out the hypothesis of secondary cancer induced by chemotherapy or radiotherapy. Vigilant monitoring and personalized management strategies are essential, necessitating further research to elucidate molecular mechanisms and inform clinical practice.

Conclusions:

In conclusion, while the association between RCC and multiple myeloma remains complex and multifactorial, accumulating evidence suggests a potential link between these two malignancies. RCC-MM association has certain unique characteristics such as; (i) shared risk factors like obesity (increased IL-6 production by adipose tissue),hypertension, smoking; (ii) similar cytokine requirements; and (iii) lytic bone lesions. Both myeloma and RCC appear to benefit from therapies such as those directed against cytokines (TNF-α receptor blocker), immunomodulators drugs like thalidomide/lenalidomide, proteasome inhibitor (bortezomib), and autologous stem cell transplantation, although results have been more satisfying for MMs than metastatic RCCs. The biological behaviour of MM following RCC has been very aggressive. This may be explained by high-grade myeloma cell morphology, advanced histological stage, possible underlying adverse cytogenetic alteration and poor response to chemotherapy. Any new lytic bone lesions in a patient with prior RCC should be carefully evaluated for possible myeloma; especially in the absence of pulmonary or visceral metastases. All patients of MM should be carefully evaluated for complex mass lesion in the kidneys.

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.