Glioblastoma is the most common adult primary brain tumor that occurs in the central nervous system and is characterized by rapid growth and diffuse invasiveness with respect to the adjacent brain parenchyma, which renders surgical resection inefficient. Although it is a highly infiltrative tumor, it is rarely disseminated beyond the central nervous system, wherein extracranial metastasis is a unique but rare manifestation of this kind of tumor. It is very common for acquired immunodeficiency syndrome (AIDS) patients to be infected with the human immunodeficiency virus (HIV), which suggests that a possible association between HIV infection and tumor development exists. In this paper, we present a new case of a young patient's HIV-associated glioblastoma, with glioblastoma metastasis within the T9 vertebral body and lymph nodes in the anterior neck tissue. Initially, the patient was diagnosed with a grade III plastic astrocytoma. The patient lived a normal life for a year while being treated with temozolomide, radiotherapy, and highly active antiretroviral therapy. However, the tumor quickly evolved into a glioblastoma. We believe that the drastic progression of the tumor from a grade III anaplastic astrocytoma to a metastatic glioblastoma is due to the HIV infection that the patient had acquired, which contributed to a weakened immune system, thus accelerating progression of the cancer.