gms | German Medical Science

The case of a five-year-old child is presented, who had left sided sensorineural hearing loss, lower motor neuron facial weakness on the left side (HB grade 3), and gait ataxia. A brain MRI with gadolinium showed a homogenously enhancing lesion that fills the internal auditory canal (IAC) and extends into the cerebellopontine angle with brain stem compression and associated edema in the brain stem. CT scans of the brain with bone window showed widening and erosion of the left IAC. Open biopsy performed in another hospital resulted in neuropathological diagnosis of a teratoma. Microsurgical tumor excision was performed through a retrosigmoid approach. The tumor was hardly dissected from the brain stem. Since both facial and cochlear nerves were infiltrated by the tumor, they could not be preserved. The proximal and distal ends of the facial nerve were not available; hence early hypoglossal facial anastmosis was performed 2 weeks later. Pathology showed well-differentiated skeletal muscle fibers and individual ganglion cells, with no evidence of malignant changes. Muscle fibers showed diffuse immunoreactivity for Desmin, and ganglion cells stained for Neurofilament. The diagnosis of rhabdomyoma was made.

Rhabdomyoma is an extremely rare pathological entity in the CPA. There are several case reports of hamrtomas and choristomas in the CPA, but so fare only another case of rhabdomyoma has been described in literature. We suggest that early exploration of this congenital tumor increases the chance of successful radical surgery.