Pleomorphic Xanthoastrocytoma: A Single Institution Experience
Cristiane M Ida, Kiernan J Minehan, Sarah M Jenkins, Nadia N Laack, Bernd W Scheithauer, Caterina Giannini. Mayo Clinic, Rochester, MN; Mayo Clinic, La Crosse, MN
Background: Pleomorphic xanthoastrocytoma (PXA), a rare astrocytic tumor with relatively favorable prognosis, corresponds to WHO grade II. It is currently uncertain if PXA with histological features of anaplasia, so-called “PXA with anaplastic features” (PXA-AF), should be considered anaplastic (WHO grade III).
Design: We studied 49 patients operated at (39) or referred to (10) our Institution, with histologically confirmed PXA (1950-2011). Clinical and therapeutic data and follow-up were obtained from medical records. Slides available for review in 66 tumors from 46 patients (13 with ≥ 2 resections) were reassessed for features of anaplasia, including mitotic index (MI) ≥ 5/10 HPF, necrosis (N) and endothelial proliferation (EP). Recurrence-free and overall survival were estimated with Kaplan-Meier methods and compared between PXA and PXA-AF with log rank tests.
Results: Patients included 28M and 21F, median age at diagnosis 21.5 yrs (8-57). Tumors were supratentorial in 47 cases (43% involving temporal lobe). Seizures were the presenting symptoms in 64% of patients. Extent of tumor removal was total in 24, subtotal in 20, biopsy-only in 1 and unknown in 4 cases. Features of anaplasia (PXA-AF) were present in 16 cases (13 at first resection; 3 at recurrence), and included MI ≥ 5/10 HPF (7), N (2), MI ≥ 5/10 HPF + N (4), MI ≥ 5/10 HPF + EP (1) or MI ≥ 5/10 HPF + N + EP (2). Median follow-up was 5 yrs (0.1-29.1) and 3.4 yrs (0.1-19.3) for PXA and PXA-AF, respectively. Recurrence occurred in 19 patients: 14 PXA (39%), 4 of which also progressed to PXA-AF, and 5 PXA-AF (38%). Three (of 36) patients with PXA died of disease, and all had progressed from PXA to PXA-AF (at 0.3, 3 and 3.6 yrs from progression). Three (of 13) patients with PXA-AF died of disease (at 0.9, 1.1 and 4.7 yrs from first resection). After first resection, 10 PXA patients and 6 PXA-AF patients received radiotherapy, chemotherapy or a combination. Additional treatment generally followed recurrence. Recurrence-free 5-year survival rates were 75% and 50% (p=0.34) and overall 5-year survival rates were 95% and 82% (p=0.05) for PXA and PXA-AF patients, respectively.
Conclusions: This study confirms that overall survival is significantly decreased in PXA-AF when compared to classic PXA, raising the consideration that PXA-AF may correspond to a higher grade tumor.
Monday, March 19, 2012 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 277, Monday Morning