Glioblastoma multiforme (GBM) is the most common primary brain tumor and the most malignant astrocytoma in adults, with rare extra-cranial metastases, especially for subcutaneous metastases. It could be easily misdiagnosed as primary subcutaneous tumor. In this report, we describe a patient with pontine GBM who developed a subcutaneous swelling at the ipsilateral posterior cervical region 8 months after operation, and the pathological and immunocytochemical examination carry the same characteristics as the primary intracranial GBM cells, which defined it as subcutaneous metastasis. GBM with subcutaneous metastasis is extremely rare, and knowledge of a prior intracranial GBM, pathological examinations and immunocytochemical tests with markers typically expressed by GBM are of vital importance for the diagnosis of GBM metastasis. Surgical resection of subcutaneous swelling, followed by chemotherapy and radiotherapy, could be the best strategy of treatment for the patients with GBM subcutaneous metastasis.