Case 11/2011 B. Lach Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ont. CANADA Abbreviations used: B-brain, M-meningioma, SMA smooth muscle actin, SA-sarcoma, EMA – epithelial membrane antigen

76yo, history of multiple myeloma Lytic bone lesion MRI: intracranial/extracranial extra-axial tumour. Total resection

Recurrent tumour three years later P53 MIB-1

B M M SA SA SA SMA EMA RETICULIN M M SA SA SA M MIB-1 P53 CD10 SA B SA SA M

Additional two cases with similar clinical course and histological features.

N Reticulin Myofilaments SMA + Fibronexus Case #2: 55 y.o.only meningioma in the first surgery N Recurrent tumour one year later: only sarcoma Reticulin Myofilaments SMA + Fibronexus Only myofibroblastic sarcoma in two subsequent surgeries. Four year survival.

Case #3: 64 yo: first surgery: atypical meningioma SMA Recurrence, 5 yrs later: Mixed meningioma/sarcoma SMA MIB: 10%+ GFAP g h EMA CD10 P53

a c b Case #3 Myofibroblastic differentiation of tumour cells

MYOFIBROBLASTIC SARCOMA (MFSA) IN ANAPLASTIC MENINGIOMA Three similar cases in personal collection: all developed in recurrent malignant meningiomas invading brain Two mixed, myofibroblastic sarcoma/meningioma and one pure myofibroblastic sarcoma: MFSA strongly positive for smooth muscle actin, vimentin and reticulin All developed on the side of infiltrated brain All show high MIB-1 and P53 immunoreactivity All rapid growth of recurrent tumour DIAGNOSIS: MYOFIBROBLASTIC VARIANT OF ANAPLASTIC MENINGIOMA (“METAPLASTIC”)