Brain Pathology Case of the Month - August 2004

Contributed by Luca Papavero, Christian Hagel *, Ulrich Grzyska #, Eric Fritsche and Manfred Westphal*
Departments of Neurosurgery, *Neuropathology and #Neuroradiology
   University Hospital Hamburg Eppendorf, Hamburg, Germany


A man in his mid-sixties complained about an increasing sense of abdominal "constriction" over a two years period. Eighteen months after the onset of this symptom additional tingling of the legs was perceived. Half a year later mild gait ataxia developed although there was no evidence of gross motor or sensory deficits. A painful micturition prompted the patient to undergo a detailed neurological investigation. The clinical finding consisted of a mild muscular weakness at the lower limbs associated with sensory disturbances.


The thoracic MRI showed a fusiform enlargement of the spinal cord extending from T5 to T8 with maximum at T7. The lesion was iso-intense in the T1- weighted images (Figures 1a) with inhomogeneous Gadolinium enhancement (Figure 1b). The impact on the spinal cord was best depicted by the T2-weighted images (Figure 1c). The gadolinium enhanced sequences revealed two components. The larger one was an exophytic dorsal lesion accompanied by a cuffing of the cord with multiple small, enhancing micronodules. The other was intramedullary (Figures 1d-1f).


The enlarged portion of the spinal cord was approached via a two level laminoplasty (T6+T7). The exophytic lesion was pinpointed by using ultrasound localizer. After opening the dura a cherry stone sized pinkish tumor extruding from the spinal cord became apparent (Figure 2a) and was resected. The granular enhancement on the surface of the cord shown in the axial MRI turned out to be wart-like tumor portions protruding from the cord at root entry zones and was also biopsied (Figure 2b). Taking into account the age of the patient, his substantially intact neurological function and the apparent diffuse growth pattern it was felt that an aggressive tumor resection was not possible.


Three samples from different locations of the tumor were investigated. Macroscopically the tissue presented as a red-white soft mass. The surface had a glossy, translucent appearance. Upon histological most areas showed a loose microcystic texture with few Rosenthal fibers (Figures 3a, b; arrows: Rosenthal fibers). The multipolar tumor cells had long hair-like cytoplasmic processes. In addition, a fibrillar growth pattern with bipolar tumor cells was observed in small areas. Nuclear pleomorphism was apparent with oval and irregularly shaped nuclei of medium size with fine or coarse, frequently hyperdense chromatin. Neither mitoses or necroses were observed. A prominent vasculature consisting of small to medium sized vessels was noticed. Some of the vessels showed fibrotic changes or endothelial hyperplasia. Further, a perivascular lymphocytic infiltration was found (Figure 3a). Immunohistochemically the cells were GFAP positive (Figure 3c). Ki-67/MIB-1 labeling index was 5% (6/137 nuclei in 0,1 mm2). Some of the nuclei showed an accumulation of p53 protein (< 1%).


International Society of Neuropathology