Tumour lysis syndrome (TLS) is a potentially fatal complication of malignancy or its treatment. This uncommon syndrome comprises laboratory findings of hyperuricaemia, hypocalcaemia, hyperkalaemia and hyperphosphataemia. A literature search revealed a total of eight patients, with testicular cancer, who had TLS. All these patients had metastatic disease. We present a unique case of a 47-year-old gentleman we saw in clinic, who presented with a rapidly growing right groin mass and acute breathlessness, and discuss the diagnosis and management of TLS. TLS is extremely rare in testicular cancer but necessitates the awareness of urologists. TLS can occur spontaneously in testicular malignancy. Cell lysis in a rapidly proliferating germ cell tumour is a possible mechanism. The prompt identification and institution of management for TLS is crucial to improve clinical outcomes.