Tumour thickness in malignant melanoma: the limitations of frozen section.

This paper reports a prospective study to compare maximal tumour thickness values of the same lesion obtained by frozen and paraffin sections in 20 patients with malignant melanoma over a one-year period. Significant differences were found between tumour thickness values obtained by frozen section and paraffin section. There was no constant relationship between the two sets of values. As present prognostic and therapeutic criteria are based on tumour thickness measurements obtained from paraffin sections, we recommend that clinical decisions should not be based on results obtained from frozen sections.