Medullary thyroid carcinoma (MTC) is a rare type of neuroendocrine tumor, accounting for 3%-4% of all thyroid cancers. Seventy-five percent are sporadic, of which 60% have pathogenic REarranged during Transfection (RET) somatic mutations. The sporadic RET-mutated MTC poses novel challenges for targeted treatment. The authors present a case of a 60-year-old male diagnosed in 2018 with MTC who underwent total thyroidectomy with sternotomy and bilateral cervical lymph node dissection - pT3N1b R1 L1 V1 Pn0 cM1 (hepatic and lung metastasis). According to the decisions made by the multidisciplinary tumor board, the patient received multiple palliative systemic treatments. Despite an initial response, vandetanib was accompanied by grade 3 high blood pressure and progression after 14 months of treatment. The patient also received cabozantinib, which led to an initial response, but with grade 3 hypertension and skin toxicity. The patient progressed, including symptomatic bone metastasis, after 15 months of treatment. Following the next sequencing genome result, which showed a somatic mutation in the RET M918T gene, the patient was treated with selpercatinib, a highly selective and potent RET inhibitor. The treatment led to clinical and radiological responses without significant toxicities. The objective of this case report is to highlight the impact of innovative treatment and precision medicine on the management of cancer patients, which not only has a direct effect on their survival but also on their quality of life.