Pediatric astrocytomas with monomorphous pilomyxoid features and a less favorable outcome.
Among tumors classified as pilocytic astrocytoma (PA) in the Johns Hopkins Hospital Department of Pathology files, we identified 18 cases with a distinctive monomorphous pilomyxoid histological pattern and a higher recurrence rate than that of PA with classical histological features (classical PA). The majority of the tumors occurred in infants and young children and involved the hypothalamic/chiasmatic region. The tumors were histologically similar to PA, but they were more monomorphous and more myxoid. Rosenthal fibers were not seen and only 1 of 18 tumors had eosinophilic granular bodies. At the end of the follow-up period, 6 patients were dead and 12 were alive with evidence of disease. Progression free survival (PFS) at 1 year was 38.7%. In comparison, we identified a control group of 13 classical PAs in the same age range and location as the study group. In this group, PFS at 1 year was 69.2%, which was significantly better than that for pilomyxoid tumors (p = 0.04). There was no CSF dissemination or death due to tumor progression among patients with classical PA. Eight of these patients are alive with recurrent disease, and 4 have no evidence of disease. While the monomorphous pilomyxoid tumors have some resemblance to classical PA, our results suggest that the former is a more aggressive variant or a separate entity that needs to be recognized for prognostic purposes.
Tihan
T
T
Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, USA.
Fisher
P G
PG
Kepner
J L
JL
Godfraind
C
C
McComb
R D
RD
Goldthwaite
P T
PT
Burger
P C
PC
D001254:Astrocytoma / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery / Q000628:therapy; D001932:Brain Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery / Q000628:therapy; D002648:Child; D002675:Child, Preschool; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D011379:Prognosis