Metastatic clear cell renal cell carcinoma to the forearm without identifiable primary renal mass

Area of Science:

• Oncology
• Dermatology
• Urology

Background:

• Kidney cancer, predominantly clear cell renal cell carcinoma (RCC), is a common malignancy in the U.S.
• Metastatic RCC usually involves identifiable primary tumors with common sites like lung, bone, liver, and brain.
• The occurrence of metastatic RCC without a detectable primary renal tumor is exceptionally rare.

Observation:

• A 52-year-old male presented with a rare cutaneous metastasis of renal cell carcinoma.
• No primary renal tumor was identifiable in the patient at the time of diagnosis.
• The metastasis manifested in the skin, an uncommon site for RCC spread.

Findings:

• The case highlights an unusual presentation of metastatic renal cell carcinoma.
• Cutaneous metastasis of RCC can occur even when the primary tumor is not readily detected.
• This case expands the known spectrum of metastatic patterns for renal cell carcinoma.

Implications:

• This case underscores the importance of considering rare metastatic sites in cancer diagnosis.
• Further research may be needed to understand the mechanisms behind primary-tumor-absent metastatic RCC.
• Clinicians should maintain a high index of suspicion for metastatic disease, even in the absence of a clear primary source.