A 14-yr-old boy presented to the emergency department after a head-to-head collision that occurred while being tackled during a pick up football game at school. He experienced a brief loss of consciousness lasting several seconds. In the emergency department, he was awake, alert, and oriented, with a Glasgow Coma Scale of 15. Physical examination was unremarkable, with the exception of a small frontal hematoma lateral and superior to the right orbit. A noncontrast head computed tomography (CT) revealed no acute fracture or hemorrhage. A large right-sided intraventricular brain mass was incidentally noted.
A follow-up brain magnetic resonance imaging scan confirmed the presence of a 6.9 × 5.7 × 5.6 cm partially bilobed mass within the atrium of the right lateral ventricle, with mass effect and mild right-to-left midline shift (Fig. 1). The mass was surgically resected 4 wks after the initial injury and, on pathologic examination, was diagnosed as a benign schwannoma. The patient did well postoperatively and, at 1 mo follow-up, was walking and running unassisted, without balance deficits or identifiable gait asymmetry. In retrospect, other than mild occasional headaches in the preceding year, the patient was asymptomatic before this minor head injury.
Schwannomas are slow growing, typically benign1 encapsulated tumors that are usually solitary, except when seen in association with neurofibromatosis type 1. Intracranial schwannomas may be encountered incidentally but, more commonly, are discovered after symptoms develop as a result of mass effect on the brain or a cranial nerve. Treatment for larger tumors usually involves surgery.2
We note that patients with mild traumatic brain injury, or concussion, are not always evaluated with head CT. There remains some controversy regarding when to obtain a head CT in a patient with mild head injury, and many guidelines addressing this issue are in print. On the basis of the Canadian CT Head Rule,3 a head CT was not required in this patient, as he did not meet any of the seven criteria. In contrast, based on the New Orleans Criteria,4 a head CT was indicated because of the presence of a headache. The purpose of imaging in this setting is not to detect incidental brain lesions. However, in this case, imaging led to early detection of a large brain mass, which may have led to a better outcome than would have occurred if the diagnosis was further delayed.
1. Asthagiri AR: Current concepts in management of meningiomas and schwannomas. Neurol Clin
2. Abeloff M: Clinical Oncology
, ed 3. New York, Churchill Livingstone, 2004
3. Stiell IG, Wells GA, Vandemheen K, et al. The Canadian CT Head Rule for patients with minor head injury. Lancet
4. Stiell IG, Clement CM, Rowe BH, et al. Comparison of the Canadian CT Head Rule and the New Orleans Criteria in patients with minor head injury. JAMA