Brain Pathology Case of the Month - June 2000

Contributed by Klaus Kuchelmeister MD1, Michael Winking MD2, Monika Hügens-Penzel MD3, Dieter-Karsten Böker MD2, Walter Schachenmayr MD1
1Institute of Neuropathology, 2Neurosurgical Clinic, 3Department of Neuroradiology, University of Giessen, Germany
Published on line in June 2000


A 68-year-old woman reported an 8-year history of progressive hearing loss of the left ear leading to anacusis. She also complained about left-sided tinnitus, intermittent trigeminal neuralgia and vertigo. Clinically, there were no additional neurological deficits and no signs of von Hippel-Lindau (VHL) disease.

Cranial computed tomography (CCT) and magnetic resonance imaging (MRI) disclosed a tumor in the left cerebellopontine angle with destruction of the petrous bone and the internal acoustic meatus and involvement of the inner and middle ear and the jugular foramen. In MRI, the tumor was inhomogenously hyperintense in T2-weighted images and showed strong contrast enhancement in tT1-weighted images (Fig. 1). There was no brainstem compression. Radiological diagnosis was jugular paraganglioma.

Angiographic embolization of the tumor was performed. It was fed through left-sided branches of the medial meningeal artery, of the occipital artery, of the pharyngeal and auricular artery and of the anterior inferior cerebellar artery.

Intraoperatively, the tumor was highly vascularized and partly cystic. It infiltrated and destructed the petrous bone, and its intracranial portion showed a focally intradural location without leptomeningeal or brain infiltration. The left cranial nerves V, VII and VIII were adherent to the neoplasm. The intracranial tumor part was completely resected. 4 weeks later residual tumor in the petrous bone was removed.


Paraffin sections of the first biopsy showed a papillary, partly cystic adenoid epithelial tumor with a variable content of fibrovascular stroma (Fig. 2a). Sometimes, epithelial cells formed glandular structures of varying sizes, some of which contained eosinophilic colloid-like material resembling thyroid follicles (Fig. 2b). The papillary, cystic and glandular formations were lined by a single row of cuboidal to low columnar, sometimes more flattened cells with eosinophilic cytoplasm or cytoplasmic vacuoles (clear cells) (Fig. 2a-c). There was no nuclear pleomorphism; the round-oval nuclei were of moderate chromatin density. Sometimes intranuclear vacuoles (´Lochkerne`) were seen. Mitoses and necroses could not be observed. The tumor stroma showed variability in cellularity and fiber content and was rich in capillaries which often lay directly subjacent to the epithelium (Fig. 2c). Portions of dura mater with focal infiltration but not penetration by the tumor cells and some small fragments of bone were seen in the tumor. No leptomeningeal or brain tissue was present. Focally, intravasal embolization material accompanied by foreign body giant cells was observed.

Prussian blue reaction revealed some large siderophages in the cystic spaces and focal siderosis of tumor cells. Most of the epithelial cells showed (diastase-sensitive) PAS-positivity, but no staining with Alcian blue. The colloid-like material in glandular lumina was strongly PAS-positive (diastase-resistant).

Immunohistochemical preparations showed strong cytokeratin- (antibody KL1) (Fig. 3a) and EMA-immunoreactivity of the tumor cells. Many cells were also vimentin-positive, mostly with staining of the basal portion of their cytoplasm (Fig. 3b). Some cells showed a weak to moderate NSE-immunoreactivity. There was no immunohistochemical detection of GFAP, S-100 protein, synaptophysin, chromogranin A, neurofilament protein and thyroglobulin and no unequivocally specific transthyretin-immunoreactivity in the tumor cells. MIB1 labeled only very rare tumor cell nuclei (labeling index <1%) (Fig. 3c).


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