Virtual Microscope
A 49 year-old woman with left side weakness and an extra-axial spinal cord tumor
Elizabeth Rushing, M.D., Col.
Department of Neuropathology and Ophthalmic Pathology, Armed Forces Institute of Pathology, Washington, D.C.
Last updated: February 28, 2006
Clinical Information: The patient was a 49 year-old female who presented with left-sided weakness and gait ataxia. Imaging studies revealed an extramedullary, intradural spinal cord tumor at L3-4. The preoperative diagnosis was a schwannoma. A microdiscectomy was performed and gross total excision was achieved.
Diagnosis: Clear cell meningioma (WHO grade II).
Pathology: The tumor is composed of rather monotonous appearing, clear polygonal cells with delicate but distinct cell membrane. The nuclei do not appear particularly high grade. A variable amount of collagen is also present. A small number of cells are positive for epithelial membrane antigen (EMA). The tumor cells are negative for cytokeratin stain or inhibin.
Comment: A clear cell epithelioid neoplasm in an extra-axial location of either the brain or spinal cord should be treated with care as a few common entities. The possibility of metastatic clear cell carcinoma, particularly metastatic low-grade conventional renal cell (clear cell) carcinoma must be ruled out. Prostatic carcinoma, partcularly those have been treated with chemotheraly, may also produce meningeal metastases featured by low grade clear cells. These meningeal metastasis may closely mimic meningioma on MRI and gross examination. Morphological identification of glandualr architecture is very helpful but may require diligent search. Metastatic carcinoma are usually strongly positive for cytokeratin. Although some cytokeratin staining may be present in meningioma but the proportion of areas that are positive is usually much less than those of metastatic carcinoma. Other specific markers such as prostate specific antigen can be used to demonstrate the prostate lineage if the metastasis turn out to be prostate carcinoma. Hemangioblastoma can also occur in the spinal cord and may have resemblance to clear cell meningioma. Immunohistochemical positivity can usually be demonstrated in hemangioblastomas.
It is important to recognize clear cell meningioma as they are of WHO grade II and would behave more aggressively.