Contributed by Andrea M. Faymonville, MD1, Christoph Kabbasch, MD2, Tobias Blau, MD3, Roland Goldbrunner, MD1, Stefan Grau, MD1
Departments of 1Neurosurgery, 2Neuroradiology, 3Neuropathology, University of Cologne, Germany
A 66-year-old man with a medical history of metastatic prostate cancer (Stage IV) had undergone systemic chemotherapy until June and received hormone therapy since then. Regular follow-up examinations showed stable disease. A bone scintigraphy two weeks prior to presentation showed known diffuse metastases throughout the skeleton, excluding the cranium. In August the patient presented to the emergency room with a 10 day history of progressive right-sided facial pain, diplopia and drooping of his right upper eyelid. On physical examination he was alert and complained about right deep orbital pain, numbness down the right side of his face and horizontal diplopia.
Neurological examination showed cranial nerves I-V and VII-XII intact, an severe abducens nerve palsy and a slight ptosis on the right side. The right pupil was slightly dilated but round and reactive to light. Ocular fundi were normal. The right-sided facial pain followed the distribution of the first and second branch of the trigeminal nerve. Hypo- and paresthesia was stated along the distribution of all three divisions of the right trigeminal nerve.
Complete blood count and the serum examination were within normal ranges except for a slight elevation of the prostate -specific antigen level (35µg/l).
A contrast CT scan including bone windows showed a hyperdense lesion adjacent to the right petrous apex and sphenoid wing and was interpreted as meningioma (Figure 1). On MRI, a homogenous lesion involving the right petrous apex and the medial sphenoid wing infiltrating the ipsilateral cavernous sinus was revealed (Figure 2). The mass appeared hypointense in T2-weighed images and showed only slight contrast-enhancement in T1-weighed images. The white matter of the right temporal lobe including the amygdala showed signal enhancement in T2WI, suggesting edema. There were no signs of bone metastasis to the skull based on CT and MR imaging. Differential diagnoses based on neuroimaging were meningioma of the petrous-temporal bone, extra-axial metastasis and primary brain tumor.
The rapid progression of the patient's clinical signs was atypical for the clinical presentation of a meningioma. Thus the patient underwent craniotomy for partial resection of the tumor via a pterional/ subtemporal approach. Intra-operatively, an extra-axial tumor with soft consistency and mild vascularization was found. The intraoperative tumor morphology was not typical for meningioma; thus smear preparations were initiated, which showed a highly proliferative tumor suspicious for malignant glioma.
Standard hematoxylin and eosin studies showed pleomorphic epithelial cells with high density and frequent mitosis (Figure 3, arrows) and a high proliferative activity, indicated by expression of the Ki-67 antigen of up to 60% (Figure 4). Tumor cells showed strong expression of the prostate-specific antigen (PSA) (Figure 5) and prostate-specific acid phosphatase (PSAP) (Figure 6). What is the diagnosis?