Gastrointestinal stromal tumor with intracranial metastasis: case presentation and systematic review of literature

Background: Intracranial metastasis of Gastrointestinal Stromal Tumors (GISTs) is rare but presents unique treatment challenges. We present a case of intracranial metastasis of GIST with a systematic review of the literature. A literature search using key terms "'gastrointestinal stromal tumor' AND brain AND metastasis"" was conducted through May 2019 via Embase and Pubmed according to PRISMA guidelines. Only cases describing intradural metastases rather than calvarial or intraorbital metastases were included.

Case presentation: A 57-year-old woman with history of GIST metastatic to the liver presented with a six-week history of left facial weakness, left hearing loss, and left facial numbness, and a one-week history of headaches, gait disturbance, and dizziness. MRI revealed a contrast-enhancing dural-based left middle cranial fossa mass measuring 2.9 cm × 3.1 cm × 3.4 cm with extension into the internal auditory canal and cerebral edema. A left temporal craniotomy was performed to excise the lesion, and the patient was discharged to a rehabilitation facility at her preoperative baseline. Intraoperative pathology revealed a spindle cell neoplasm, postoperative MRI demonstrated gross total resection of the lesion, and microscopic analysis demonstrated sheets of spindled tumor cells with short ovoid, irregular, hyperchromatic nuclei and scattered large atypical nuclei without extensive necrosis. Immunohistochemical staining was positive for KIT proto-oncogene (CD117, c-KIT), and the patient was put on imatinib (400 mg/day).

Conclusions: Of the 18 cases analyzed and our present case, metastasis typically involved the cerebrum with only one in infratentorial elements. The tumors in seven of the cases involved the dura, and one case metastasized to the pituitary. Eight patients died following treatment. Surgery remains the mainstay of intracranial metastatic GIST, however there are many reports of good responses to radiation or chemotherapy alone. More investigation is required to determine the best treatment course for these patients.