Cobb syndrome is a rare neurocutaneous disease characterized by vascular anomalies involving the skin and spinal cord at the same metamere. The most common initial symptoms are neurological manifestations such as pain, monoparesis, headache, scoliosis, and motor damage. We present two patients with Cobb syndrome and severe disease burden harboring somatic mutations in KRAS. The two patients were subsequently treated with the MEK inhibitor trametinib, indicating the potential therapeutic benefit of this treatment for patients with life-threatening Cobb syndrome who are currently considered incurable.