The most malignant type of intrinsic brain tumor is glioblastoma (WHO grade IV). Primary leptomeningeal spread is rare and leads to a variety of differential considerations, as there is no typical clinical or imaging pattern. Here we present a rare and uncommon case of a primary leptomeningeal glioblastoma in combination with a low-grade glioma in a 21-year-old male, initially presenting with only headache and lower back pain. The presented case illustrates the challenging differential considerations and the severe course of leptomeningeal glioblastomas.