A Rare Case of Sarcomatoid Variant of Mixed Germ Cell Tumor of the Testis Presenting With Malignant Hypercalcemia and Tumor Lysis Syndrome.

Hypercalcemia of malignancy is relatively common in several cancers. However, in testicular cancer, paraneoplastic hypercalcemia is uncommon. We describe the first case of severe tumor lysis syndrome associated with hypercalcemia from bone metastasis of testicular origin. Classically, tumor lysis syndrome is associated with hypocalcemia. This was a diagnostic and therapeutic challenge.