DESMOPLASTIC SQUAMOUS-CELL CARCINOMA OF SKIN AND VERMILION SURFACE - A HIGHLY MALIGNANT SUBTYPE OF SKIN-CANCER

BACKGROUND. The prognosis of squamous cell carcinoma (SCC) of the skin is directly related to the development of metastases or local recurre nce. This is affected by numerous factors, most of which are independe nt: clinical tumor size, histopathologic tumor thickness, depth of pen etration, degree of cell differentiation, degree of keratinization, lo cation, and immunosuppression. The determination of whether desmoplasi a, previously described in only one case of SCC, constitutes an additi onal prognostic factor was the objective of this study. METHODS. The s tudy was performed prospectively on 594 SCCs from 509 patients. All of the factors mentioned earlier were present. Forty-four SCCs were iden tified by light microscopy as desmoplastic due to their prominent trab ecular growth patterns, narrow columns of atypical epithelial cells, a nd marked desmoplastic stromal reaction, in some cases with perineural and perivascular invasion. Follow-up ranged from 4 to 10 years (media n, 5.3 years). RESULTS. All tumors in the study patient population wer e treated using the paraffin section method of micrographic surgery. T he 44 desmoplastic SCCs were found to metastasize 6 times more often t han the remaining 550 tumors (22.7% vs. 3.8%), with 10 times as many l ocal recurrences (27.3% vs. 2.6%). CONCLUSIONS. Desmoplasia is a highl y significant (P < 0.001) prognostic factor for SCCs and is associated with the development of metastases or recurrence. (C) 1997 American C ancer Society.