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Washington University Experience | NEOPLASMS (MENINGIOMA) | Anaplastic | 24C Case 24 Ancillary data and Denouement
Additional data & Denouement: Outside staining describes EMA, CAM 5.2 and CEA positivity. The Ki67 proliferative index is described as "very high". Cytokeratin 20 is negative. ---- FISH was performed at Washington University to assess the status of chromosomal arms 22q, 18p, 14q and 1p. Deletions of these arms are associated with meningiomas. In particular, 1p and 14q have been associated with atypical and anaplastic meningiomas as well as a higher risk of recurrence and shorter progression free survival. FISH probes to NF2 (22q12), BCR (22q11.2), DAL-1/4.1B (18p11.3), CEP18 (centromere 18), 14q32 and 1p32 were all employed. Both the 2000 and 2007 (S07-2513) specimens were tested. In the 2000 specimen, there are deletions for both 22q and 1p32. Normal dosages (i.e., two copies) of chromosome 14 are seen. Testing of chromosome 18 is non-informative. For the 2007 specimen, there is also evidence for chromosome 22q and 1p deletions. In addition, a subset of tumor cells show evidence of 14q32 deletion. Again, testing of chromosome 18 is non-informative. Notably, in the 2007 specimen, a similar pattern of chromosomal deletions is present both in the glandular and more solid tumor areas to suggest a common origin for these regions. Overall, the deletion patterns seen by FISH in both the 2000 and 2007 are in keeping with a genetically more aggressive form of meningioma. ---- Comment: The occurrence of glandular metaplasia in a meningioma is exceedingly rare, and anecdotally, we have only seen this once prior. In both cases, the glandular metaplasia occurred in the context of an anaplastic meningioma. The alternative differential diagnosis in this case would be metastasis of an adenocarcinoma to a preexisting meningioma. However, since the pattern of chromosomal deletions, which are characteristic of meningioma, are seen in both the glandular and non-glandular areas, this is essentially excluded.
