SQUAMOUS-CELL CARCINOMA OF THE SKIN - HISTOPATHOLOGICAL FEATURES AND THEIR SIGNIFICANCE FOR THE CLINICAL OUTCOME

Background Owing to the rising incidence of tumours, the question of r eliable risk classification is becoming increasingly significant. Obje ctive Participation in the multicentre carcinoma registry maintained b y the Association of Operative and Oncological Dermatology of the Germ an Dermatological Society requires, in addition to the parameters of c linical staging and grading already established by the International U nion against Cancer, description of other histopathological criteria r elated to prognosis, with special attention to microstaging. Methods O ne hundred and eighty-four patients with squamous cell carcinoma of th e skin were examined. The histological parameters, carcinoma type, Bre slow index, invasion level, growth form, grading and mitotic index wer e recorded and classified, and clinical staging was performed. Results It was found that the clinical criterion of tumour diameter (T-catego ry) determines the further course of the disease. The other parameters taken into account, namely pathohistological microstaging and grading , can increase the accuracy of prognosis evaluation, and in particular enable carcinomas of the T1-category to be classified as either high malignant or low malignant tumours. The desmoplastic squamous cell car cinoma subtype is a potential risk tumour. Endophytic tumours are more malignant in their development than exophytically-growing carcinomas, and the probability of recurrence and metastatic tumour spread furthe r increases when ulceration can be detected by microscope. In order to distinguish metastatic and recurring carcinomas, in addition to deter mining the invasion levels after Clark, measuring the Breslow index pr oved to be an important criterion. Quoting the mitotic index augmented the grading system, which further improved the reliability of maligna ncy assessment. Conclusions The TNM categories currently applied to sq uamous cell carcinomas of the skin must be supplemented by additional histological parameters which, according to our findings, permit more accurate classification of high and low malignant tumours. (C) 1998 El sevier Science B.V. All rights reserved