XXXX With Rhabdoid Features Lacking Other Histologic Features of Malignancy: A Study of 44 Cases and Review of the Literature.

@entity1 @entity1653 @entity5 @entity5606
The behavior of @entity5606 otherwise lacking malignant features remains unknown as most of the originally reported aggressive cases showed anaplastic histologic features independently of rhabdoid phenotype. We studied 44 @entity1 with @entity5606 lacking anaplastic features. Median age at diagnosis was 48.6 years (range 10-79). Location was supratentorial in 28 (63.6%), skull base in 15 (34.1%), and spinal in 1 (2.3%). @entity5 grade was otherwise World Health Organization grade I (n   =   22, 50%) or II (n   =   22, 50%). Rhabdoid cells represented <20% of the @entity5 in 12 cases (27.3%), 20% to 50% in 18 (40.9%), and >50% in 14 (31.8%). Median clinical follow-up, available for 38 @entity1 , was 5.0 years (range 0.17-14.2). Recurrence occurred in 9 @entity1 (5-year recurrence-free survival, 73.7%) with a significantly higher risk in subtotally resected @entity5 (p   =   0.043). Rhabdoid cell percentage was not associated with recurrence. Six @entity1 died (4 of disease, 2 of unclear causes); 5-year overall survival was 86.7%, a mortality in excess of that expected in grade I-II @entity1653 but much lower than originally reported. Review of 50 similar previously reported cases confirmed our findings. We suggest that @entity5606 be graded analogously to nonrhabdoid @entity5 , with caution that some may still behave aggressively and close follow-up is recommended.
