[1672] Expression of SALL-4 Distinguishes Intracranial Germ Cell Neoplasms from Other Central Nervous System Tumors

JK Deisch, D Rakheja, P Shang, CL Hladik, CL White, J Raisanen. University of Texas Southwestern Medical Center, Dallas, TX; Children's Medical Center, Dallas, TX

Background: Germ cell neoplasms are relatively uncommon intracranial tumors accounting for 0.3-0.6% of primary intracranial neoplasms in the Western hemisphere and 2-3% in Eastern Asia. Most occur in children and young adults, most in males, and most in the midline in the sellar or pineal regions. Despite the characteristic localization, diagnosis of an intracranial germ cell neoplasm may be difficult.
Design: We used immunohistochemistry to assess expression of the stem cell transcription factor SALL-4 in 30 germ cell neoplasms that occurred intracranially and 75 other central nervous system tumors including 69 neoplasms and 6 inflammatory lesions. We examined expression in 19 intracranial germinomas, 4 mature teratomas, 2 immature teratomas, 3 choriocarcinomas, and 1 embryonal carcinoma and 16 glioblastomas, 4 pilocytic astrocytomas, 5 ependymomas, 5 choroid plexus papillomas, 6 medulloblastomas, 1 rhabdoid tumor, 5 pituitary adenomas, 5 craniopharyngiomas, 7 pineal parenchymal neoplasms, 5 meningiomas, 5 primary central nervous system (CNS) lymphomas, 5 metastatic carcinomas, 2 cases of intracranial sarcoidosis, 1 of Langerhans cell histiocytosis, and 3 other nonspecific inflammatory lesions, 1 of the pituitary and 2 of the cavernous sinus.
Results: There was strong nuclear expression of SALL-4 by the neoplastic cells of all germinomas and choriocarcinomas, and the embryonal carcinoma. No cells of the mature teratoma expressed SALL-4, but there was weak nuclear expression by neuroectodermal cells in 1 of 2 immature teratomas. There was also weak nuclear expression by cells of 1 CNS rhabdoid tumor. No cells of any other primary CNS neoplasm expressed SALL-4, nor was there expression by cells of the metastatic neoplasms or any of the inflammatory lesions.
Conclusions: The findings indicate that SALL-4 is expressed by cells of primitive intracranial germ cell neoplasms but, with the possible exception of rhabdoid tumors, not other CNS neoplasms or inflammatory lesions. Immunohistochemistry to detect nuclear expression of SALL-4 may be useful in the diagnosis of intracranial germ cell neoplasms.
Category: Neuropathology

Monday, March 22, 2010 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 219, Monday Morning


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