YO2 - Paraneoplastic encephalitis in a gastrointestinal stromal tumor

Case summary

We report the case of a 49-year old Filipino woman who presented with a one-week history of body weakness, behavioral changes, and disorientation. Prior to her consult, she was diagnosed to have hypertension and type 2 diabetes mellitus, both of which were controlled. She was completing treatment for pulmonary tuberculosis. She was drowsy, followed commands inconsistently, and was disoriented. She had no fever, headache, or seizures. A firm, palpable hypogastric mass was noted on physical examination. Metabolic causes of encephalopathy were ruled out. No lesions were seen on cranial CT scan, but a small meningioma was noted on cranial MRI. Cerebrospinal fluid studies were negative for tuberculosis and bacterial growth, but IgG was elevated and HSV was positive, but the patient was not treated with antivirals, given the low index of suspicion for HSV encephalitis. Electroencephalogram showed intermittent deta slowing of the background activity of both frontotemporal areas with no epileptiform discharges. In the setting of a possible hypogastric malignancy, paraneoplastic encephalitis was considered, and the patient underwent three cycles of methylprednisolone pulse therapy, which resolved her neurological symptoms. Subsequent work ups revealed a heterogenous complex abdominopelvic mass on ultrasound. CEA, AFP, CA 19-9, and CA-125 were within normal limits. She underwent exploratory laparotomy. Intraoperatively, a 17 x 14 x 14 cm bulky firm mass rising from the jejunum was noted, for which wide resection of the jejunal mass was performed. No ovarian masses were noted. Immunohistomorphologic features (spindle cell neoplasm, CD 34 positive, CD 117 positive, DOG-1 strongly positive, SMA positive, and S100 negative) were consistent with jejunal gastrointestinal stromal tumor. She has continued to receive imatinib, with good functional capacity, and has tolerated treatment well. To our knowledge, this is the first reported case of paraneopastic encephalitis in a patient with jejunal gastrointestinal stromal tumor.

Clinical trial identification

Editorial acknowledgement