Advances in the care of the child with cancer. The importance of histologic subclassification of tumors

Cytology of embryonal rhabdomyosarcoma: a cytologic, light microscopic, electron microscopic, and immunohistochemical study of seven cases

A correlated cytologic and histologic study of seven cases of embryonal rhabdomyosarcoma is presented. The diagnosis of rhabdomyosarcoma was established by light and electron microscopy and immunohistochemistry of the operative specimens. The cytologic appearance of the smears corresponded well with the histopathologic findings. Cytologically, two main cell types were distinguished: a predominant primitive, small round cell with scant cytoplasm and a large cell with an abundant cytoplasm, sometimes tadpole- or ribbon-shaped. The tumor cells were often enclosed in a background of mucosubstances. The lack of cytologic features proving rhabdomyoblastic differentiation, such as cross-striation, necessitates the use of additional methods in the cytologic diagnosis of embryonal rhabdomyosarcoma. The value of the embedding technique for ultrastructural analysis and immunohistochemistry in the demonstration of desmin in aspirates is emphasized in the diagnosis of embryonal rhabdomyosarcoma.

Prognostic value of histopathology in advanced neuroblastoma: a report from the Childrens Cancer Study Group

We report the histopathologic findings in 420 patients with stage III and IV neuroblastoma enrolled in Childrens Cancer Study Group trials conducted from 1980 to 1983. A prospective study of individual cytohistologic features showed that outcome was related in a statistically significant manner to mitotic rate, multi-nuclearity, foam cells, ganglion cells, necrosis, and calcification, but only the latter was consistent for both stages. A similar test of four selected published classifications indicated the greatest prognostic value for the system developed by Shimada et al to distinguish favorable from unfavorable tumors. This classification proved significant in both stages and on examination of both primary and metastatic sites. Concordance in histologic assignment of prognosis by two observers was 83%. We conclude that the Shimada classification is valid and reproducible, and that it may be useful in planning therapy in advanced neuroblastoma. Selected cytohistologic parameters and the other classifications were less strongly predictive of outcome, but are worthy of continued study.

Evaluation of desmin as a diagnostic and prognostic marker of childhood rhabdomyosarcomas and embryonal sarcomas

The diagnostic and prognostic relevance of desmin expression in 80 rhabdomyosarcomas (RMS) and 5 embryonal sarcomas (ES) was examined using a peroxidase anti-peroxidase staining procedure. Fifty-nine RMS but only one ES stained for desmin (P less than 0.05). The maximum percentage of desmin containing cells was 49 in RMS compared with only 1% in ES. Desmin positivity correlated inversely with survival (P less than 0.02) in that RMS with high proportions of desmin positive cells were associated with poorer prognoses than those containing fewer desmin positive cells. If the degree of expression of desmin is related to myogenic differentiation, then our results indicate that poorly differentiated RMS tend to have a better prognosis than the well differentiated tumours. One possible explanation is that the poorly differentiated RMS respond better to chemotherapy than to well differentiated RMS. A multivariant analysis incorporating desmin staining, treatment, histology, age and gender revealed that the two most significant independent prognostic factors were treatment and histology.