The epidermal melanocyte system in patients with malignant melanoma. Quantitative and qualitative investigation of dopa positive melanocytes

Local melanoma recurrences in the scar after limited surgery for primary tumor

The clinical and histologic records of 46 consecutive patients were reviewed who during the period 1980-1993 had recurrence from melanoma in the scar after limited surgery for a skin tumor. They constituted about 50% of all patients admitted with local recurrence from melanoma during this period. At reexamination of the primary tumors, 16 were found to be malignant melanomas and 9 were nevi (four atypical and five benign). Twenty-one were missing, 11 of which had never been set for histologic examination. The median thickness of nine measurable melanomas was 0.66 mm. The recurrences in scar consisted of 34 primary melanomas: 18 superficial spreading, 4 nodular, 3 lentigo malignant, and 9 unclassified. Twelve tumors were dermal melanoma metastases. The median thickness of the 25 measurable melanomas was 0.78 mm. The 5-year overall survival was 69%. At the closing date of the study 15 patients had died, 13 of them because of disseminated melanoma. A comparison of the survival curves from this study with those from other series of melanomas with comparable tumor thickness indicates a considerably worse prognosis than is expected with such thin tumors. We believe that the considerable number of local recurrences in the form of a new primary in a scar following limited surgery supports the theory of limited field change around a primary melanoma. Furthermore, limited procedures for primary melanoma, if followed by a recurrence in the scar, worsen the prognosis.

Melanocytes in the anal canal epithelium

We studied the presence of melanocytes in the various epithelial zones of the anal canal, using a recently introduced melanocyte-specific antibody (HMB-45) together with antibody to S-100 protein. In normal and canals and in haemorrhoids, melanocytes, defined as intraepithelial HMB-45/S-100 positive cells, were frequently demonstrated in the anal squamous zone, only sporadically in the anal transitional zone, and not at all in the colorectal zone. In the epithelium surrounding, but clearly separated from, resected primary anal malignant melanomas, increased numbers of benign melanocytes were demonstrated in the squamous zone and transitional zone, but also in the colorectal zone. We interpret this finding as a tumour-induced proliferation of benign melanocytes normally present, but in very small numbers or in some way 'masked', in the epithelium of the upper anal canal. The demonstration of melanocytes in all three zones of the anal canal substantially supports the observation that malignant melanoma of the anal canal may originate not only below but also above the dentate line.

Therapeutic and clinico-pathological factors in the survival of 1,469 patients with primary cutaneous malignant melanoma in clinical stage I. A multivariate regression analysis

Therapeutic and clinico-pathological data of 1,469 patients with clinical stage I malignant melanoma of the skin without histological evidence of fibrotic areas of regression were examined by multivariate regression analysis. In accordance with a previous analysis anatomical site of tumour, tumour thickness, level of invasion, mitotic rate, ulceration, lymphocytic reaction, dominant type of invasive tumour cell, and sex were found to act as independent risk factors. The present analysis, furthermore, showed that size of resection margin, diagnostic biopsy, removal of the deep fascia, age at surgery, as well as presence and depth of nevus cells did not influence prognosis when adjusting for the independent risk factors.

The thin malignant melanoma: changing patterns of epidemiology and treatment

In the past few years a change has been noticed in the behavior of cutaneous malignant melanoma, with higher cure and survival rates. A retrospective review of all cases of primary cutaneous malignant melanoma during the years 1970-1979 in Chaim Sheba Medical Center reveals a possible explanation for this. The microscopic findings were reevaluated, diagnosis confirmed, and thickness of the tumor measured in millimeters. The number of cases diagnosed rose from eight in 1970 to 45 in 1979. A constant rise in number of thin melanomas (less than 0.75 mm in depth) was noticed. The percentage of thin melanoma rose from 11.1% of all melanomas in 1970 to 57.7% in 1979. Greater public and medical awareness of the danger of pigmented cutaneous lesions has probably triggered an earlier diagnosis of melanoma. Each suspected lesion is completely excised with a 1-cm free margin. No further excision is undertaken if a thin melanoma is diagnosed (excluding the more malignant regressing melanoma) on frozen section. Of the patients seen in 1979, 57% were spared wide excision and general anesthesia.

Biopsy and prognosis for cutaneous malignant melanomas in clinical stage I

The material comprises 225 patients. In 79 patients 35.1%) the tumour was closely excised and in a few cases biopsied before the patients underwent radical surgery. 146 patients were radically operated primarily. These two groups of patients are comparable with regard to sex, distribution of tumours on anatomical sites and the distribution of tumours with a given histological classification. We have ascertained that neither excision biopsy nor non-radical operation influences the prognosis if followed by radical operation within about 3 weeks.

The epidermal melanocytes in patients with cutaneous malignant melanoma. A transmission electron microscopic investigation

The epidermal melanocytes were studied in biopsies from clinically normal skin removed at various distances from cutaneous malignant melanomas. Melanocytes with some ultrastructural changes were found in a number of patients, which can be either contingent on genetic or inter/extra cellular factors. It is possible that cells with these changes are more instable and more easily transformed to malignant cells by external influence. Malignant cells were not demonstrated in either the epidermis or the dermo-epidermal junction. Activation was seen of the epidermal melanocytes lying in the immediate neighbourhood of the superficially spreading melanomas, which would suggest that this type of tumour is presumably able to influence the melanocytes. The most pronounced changes in the whole of the melanocyte system was found in patients with multiple melanomas, and in a patient with metastasizing malignant melanoma.