TL;DR: Renal cell carcinoma can present with polycythemia (due to increased erythropoietin) and hypercalcemia (due to PTHrP) [FA2020 p228]
So the question is what is the primary cancer? He has two tumor locations (kidney and lungs), which could be primary or from metastases.
I narrowed it down to metastatic renal cell carcinoma and bronchogenic squamous cell carcinoma (see below). The only other infoemation really given that could allow us to distinguish is the lab values indicating paraneoplastic syndromes. These are both known to cause paraneoplastic syndromes which can cause hypercalcemia. So focusing on the polycythemia, this is more specific for renal cell carcinoma because no lung cancer secretes EPO.
I eliminated undifferentiated carcinoma because it is too nonspecific and metastatic transitional cell carcinoma because it is rare in the kidney (with no paraneoplastic syndrome typically associated which could cause the lab abnormalities) and there is no mention of bladder.
Multiple myeloma can have renal involvement but does not typically involve the lungs and would present with bone lytic lesions and anemia rather than polycythemia. [FA2020 p431]
submitted by โcassdawg(1781)
TL;DR: Renal cell carcinoma can present with polycythemia (due to increased erythropoietin) and hypercalcemia (due to PTHrP) [FA2020 p228]
So the question is what is the primary cancer? He has two tumor locations (kidney and lungs), which could be primary or from metastases.
I narrowed it down to metastatic renal cell carcinoma and bronchogenic squamous cell carcinoma (see below). The only other infoemation really given that could allow us to distinguish is the lab values indicating paraneoplastic syndromes. These are both known to cause paraneoplastic syndromes which can cause hypercalcemia. So focusing on the polycythemia, this is more specific for renal cell carcinoma because no lung cancer secretes EPO.
I eliminated undifferentiated carcinoma because it is too nonspecific and metastatic transitional cell carcinoma because it is rare in the kidney (with no paraneoplastic syndrome typically associated which could cause the lab abnormalities) and there is no mention of bladder.
Multiple myeloma can have renal involvement but does not typically involve the lungs and would present with bone lytic lesions and anemia rather than polycythemia. [FA2020 p431]