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Histopathological features and grading in rhabdomyosarcomas of childhood
Author(s) -
WIJNAENDTS L.C.D.,
LINDEN J.C. VAN DER,
UNNIK A.J.M. VAN,
DELEMARRE J.F.M.,
VOUTE P.A.,
MEIJER C.J.L.M.
Publication year - 1994
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1111/j.1365-2559.1994.tb00530.x
Subject(s) - rhabdomyosarcoma , necrosis , grading (engineering) , medicine , pathology , histopathology , embryonal rhabdomyosarcoma , soft tissue , sarcoma , biology , ecology
Rhabdomyosarcoma represents a large group of soft tissue sarcomas displaying heterogeneous histopathological features. In addition to their histopathological classification, the variable expression of a number of histopathological features may contribute to the heterogeneity and may be related to prognosis. Tissue sections of 113 well‐documented, protocol‐treated patients with long term follow‐up (mean 6 years) were analysed by a panel of four paediatric pathologists. The following features were assessed: presence of rhabdomyoblasts, degree of maturation of rhabdomyoblasts, heterogeneous maturation patterns, mitotic activity, tumour necrosis, myxoid component, and septa. A scoring system was allocated to each index. High degree of maturation (amount of cytoplasm greater than surface area of the nucleus), absence of tumour necrosis (< 10% of tumour surface), and absence of septa (< 10% of tumour surface) significantly correlated with a favourable clinical course. Reproducibility in the assessment of these three features was good: mean κ varying from 0.53 to 0.64. A rhabdomyosarcoma score function for survival was defined by: (‐0.27 x degree of maturation score) + (0.007 x percentage septated area) + (0.031 x percentage tumour necrosis). Based on the score a two‐grade system was elaborated, i.e. grade I (score < ‐0.20) v. grade II (score < ‐0.20). Rhabdomyosarcoma grade appeared to be the best factor in predicting patients survival: 69% long‐term survival in patients with grade I v. 33% in patients with grade II ( P = 0.0001). Moreover, this grading system was shown to have discriminative power within the group of patients with embryonal rhabdomyosarcoma: patients with a grade I tumour fared significantly better than those with a grade II tumour (63% v. 41% long‐term survival, P = 0.03). This study, therefore, demonstrated the prognostic value of this grading system and its useful application within the group of patients with embryonal rhabdomyosarcomas.