[Malignant fibrous histiocytoma. Prognostic value of the histological findings]

Surgical specimens after excision of malignant fibrous histiocytomas from 41 patients were classified histologically according to subtype; semiquantitatively by cell content, mitosis count, necrosis tendency and cell polymorphism; and "subjective grading". There was no significant difference in survival time between storiform-pleomorphic and myxoid subtypes. The marked scatter in the storiform-pleomorphic subtype reflects the inhomogeneity of this group. Analysis of the individual semiquantitative criteria gave better results. Cases with many mitoses, many necroses, marked cell polymorphism and high cell content had significantly shorter survival times than those with less marked changes. "Subjective grading" was also of prognostic value. However, overlapping of prognostic factors and limitations due to tumour biology allow of only a rough orientating prediction based on histological assessment of malignancy grade.