No abstract

ALM, as diagnosed by current histological criteria, occur on the palms, soles and subungual sites, and have a poor prognosis.

tion, degree of keratinization, location, and immunosuppression. The determination of whether desmoplasia, previously described in only one case of SCC, consti-1 Dermatological Clinic, University of Tübingen tutes an additional prognostic factor was the objective of this study. School of Medicine, Tübingen, Germany. METHODS.The study was performed prospectively on 594 SCCs from 509 patients. Institute of Pathology, University of TübingenAll of the factors mentioned earlier were present. Forty-four SCCs were identified School of Medicine, Tübingen, Germany.by light microscopy as desmoplastic due to their prominent trabecular growth patterns, narrow columns of atypical epithelial cells, and marked desmoplastic stromal reaction, in some cases with perineural and perivascular invasion. Followup ranged from 4 to 10 years (median, 5.3 years). RESULTS.All tumors in the study patient population were treated using the paraffin section method of micrographic surgery. The 44 desmoplastic SCCs were found to metastasize 6 times more often than the remaining 550 tumors (22.7% vs. 3.8%), with 10 times as many local recurrences (27.3% vs. 2.6%). CONCLUSIONS.Desmoplasia is a highly significant (P õ 0.001) prognostic factor for SCCs and is associated with the development of metastases or recurrence.

Human skin reconstructs are three-dimensional in vitro models consisting of epidermal keratinocytes plated onto fibroblast-contracted collagen gels. Cells in skin reconstructs more closely recapitulate the in situ phenotype than do cells in monolayer culture. Normal melanocytes in skin reconstructs remained singly distributed at the basement membrane which separated the epidermis from the dermis. Cell lines derived from biologically early primary melanomas of the radial growth phase proliferated in the epidermis and the basement membrane was left intact. Growth and migration of the radial growth phase melanoma cells in the dermal reconstruct and tumorigenicity in vivo were only observed when cells were transduced with the basic fibroblast growth factor gene, a major autocrine growth stimulator for melanomas. Primary melanoma cell lines representing the more advanced stage vertical growth phase invaded the dermis in reconstructs and only an irregular basement membrane was formed. Metastatic melanoma cells rapidly proliferated and aggressively invaded deep into the dermis, with each cell line showing typical invasion and growth characteristics. Our results demonstrate that the growth patterns of melanoma cells in skin reconstructs closely correspond to those in situ and that basic fibroblast growth factor is critical for progression.

For histological control of excisional margins, routinely fixed tumour specimens or, under certain conditions, specimens fixed immediately in warm formalin are processed in the histology laboratory. Strips are then cut from the undersurface, edge, and cross-section of the remainder of the specimen and processed further by routine paraffin techniques until H&E-stained sections of the entire periphery and mid-section are available. We suggest that the method is simple, easy to apply, and suitable for the assessment of excisional margins of a variety of skin tumours. Extremely low recurrence rates over a relatively long follow-up period substantiate the effectiveness of the method.