Yves Merot

The spectrum of minimal deviation melanoma: A clinicopathologic study of 21 cases

A retrospective study of 21 patients with the histopathologic diagnosis of minimal deviation melanoma (MDM; n = 18) and borderline melanoma (BM; n = 3) was undertaken to determine the prognosis for these patients compared with that for patients with other types of malignant melanoma. The findings indicate that the prognosis for these uncommon nevomelanocytic tumors is somewhat better than that for other malignant melanomas. Follow-up periods in this series ranged from 18 to 96 months (mean, 57 months). Primary lesions ranged in thickness from 1.6 to 10.4 mm. The histopathologic subtypes included the Spitz variant (nine patients), the spindle cell variant (six patients), the combined spindle and epithelioid cell type (three patients), and the small epithelioid cell type (three patients). Only two of the patients died of widespread metastatic disease. Comparison of the histologic and clinical prognostic indicators of mortality in patients who have malignant melanoma with the clinical and pathologic features seen in this series of 21 patients would appear to indicate a diminished tendency toward metastatic or recurrent disease in patients with MDM and BM.

Juvenile chronic granulocytic leukemia, juvenile xanthogranulomas, and neurofibromatosis: Case report and review of the literature

A 22-month-old boy had xanthomatous skin lesions, neurofibromatosis, and chronic granulocytic leukemia. Histologic examination of the xanthomatous skin lesions disclosed juvenile xanthogranulomas. Twenty-three previously published cases of this association are reviewed.

Spitz nevus (large spindle cell and/or epithelioid cell nevus): age-related involvement of the suprabasal epidermis

The Spitz nevus (large spindle and/or epithelioid cell nevus) is a benign acquired melanocytic tumour found predominantly in children and adolescents. Depending on the architecture (junctional, compound, dermal) and cytology (predominance of spindle or epithelioid cells, or presence of both cell types) several variants have been distinguished. A histological feature occasionally leading to diagnostic difficulties is the involvement of the suprabasal epidermis. The present study details the occurrence of intraepidermal involvement (page-toid spread, nesting of cells, trans-epidermal elimination) according to the age of the patients. 89 cases of Spitz nevus were reviewed. There were 19 compound Spitz nevi with evidence of epidermal involvement, 56 cases of compound Spitz nevi without evidence of epidermal involvement and 14 cases of dermal Spitz nevi. The epidermal involvement mainly consisted of nesting of nevus cells above the basal cell layer, 9 cases clearly showing evidence of transepidermal elimination of cell nests. Upward spread of single melanocytes (page-toid spread) was minimal and always associated with nesting or trans-epidermal elimination. The mean age of patients was significantly lower in the group of compound nevi with intraepidermal involvement (7.16±4.52 years), than in the group of compound nevi without epidermal involvement (13.18±8.88 years). The age of the latter group was significantly lower than the group of pure intradermal nevi (30.14±11.25 years). Thus, involvement of the suprabasal epidermis is not a feature of Spitz nevi in adults; in such a case the diagnosis of malignant melanoma should be considered.

Pemphigus-Like IgA Deposits and Vesiculo-Pustular Dermatosis in a 10-Year-Old Girl

Pemphigus-like IgA deposits have been found to be associated with a recurrent pustular eruption in an adult reported as: ‘Intraepidermal neutrophilic IgA dermatosis’. We report here the case of a 10-y

Anetodermic prurigo nodularis (with Pautrier's neuroma) responsive to arotinoid acid

A woman had symmetrically distributed pruritic nodules for more than 40 years. Microscopically they were characterized by proliferation of nonmyelinated nerve fibers (Pautriers neuroma) and a total absence of epidermal involvement. Anetoderma developed at the site of former nodules. Her condition responded favorably to repeated retinoid therapy with regression of nodules in those sites in which retinoid dermatitis had developed.

Skin cellular retinoid-binding proteins and retinoid-responsive dermatoses

We have previously found an important increase of cellular retinoic acid-binding protein (CRABP) in psoriatic plaques whereas the cellular retinol-binding protein (CRBP) was not elevated compared to normal human skin and nonlesional psoriatic skin. In the present study we analyzed CRABP and CRBP levels in a panel of dermatoses in order to address several questions raised by the above findings. Three observations were made: CRBP showed little or no variations whereas CRABP was either normal (seborrheic keratosis, lichenification, nonlesional psoriatic and nonlesional Darier disease skin) or elevated (psoriatic plaques, lamellar ichthyosis, lesional Darier disease, pityriasis rubra pilaris, keratosis pilaris); high levels of CRABP might indicate a greater sensitivity of the lesions to systemic synthetic retinoids with a carboxyl group in the C15 position, and systemic administration of etretin increased the levels of CRABP but not CRBP. These observations suggest that CRABP might be the receptor for synthetic retinoids in the skin and that its analysis might be useful in monitoring retinoid therapy.

Systemic administration of etretin increases epidermal interleukin I in the rat

We have studied the effect of systemic administration of etretin (Ro 10–1670) on the epidermal interleukin I (ILI) pool in the rat. Hairless rats were given varying doses of etretin intraperitoneally for 21 days, or a fixed dose for 2, 8 and 16 days. Abdominal skin was taken and processed for light microscopy, autoradiography (using [3H]‐thymidine) and ILI assays. ILI was assayed in supernatants of epidermal extracts by both the lymphocyte activating factor (LAP) assay and the stimulation of prostaglandin E2 (PGE2) release from dermal fibroblasts. A significant increase in both LAF and PGE2 stimulatory activities was found during etretin administration. After 21 days’ treatment with varying doses there was a two‐ to three‐fold increase as compared to the controls, with a peak at 2 and 5 mg/kg. At a fixed dose a two‐fold increase was found after 2 days and a three‐ to four‐fold increase after 16 days; normal pretreatment values were restored 16 days after cessation of etretin.

Arotinoid Acid (Ro 13-7410): A Pilot Study in Dermatology

Ro 13-7410 was given to 29 patients (a total of 38 treatment courses) for 7.5 weeks (range 4-23). This compound is one of the most potent retinoids ever synthetized and has the highest affinity to human skin cellular retinoic-acid-binding protein. At therapeutically active doses, it did not induce the commonly seen mucocutaneous signs of retinoid toxicity such as scaling and cheilitis; over 0.5 microgram/kg body weight/day, it very frequently induced an eczematous retinoid dermatitis. This pilot study provides some indications on what appears to be in several aspects a drug quite distinct from retinoids previously used in humans.

Nucleolar organizer regions in fibrohistiocytic tumors of the skin

Nucleolar organizer regions (NORs) are loops of DNA which are present within the nucleoli of cells that possess ribosomal RNA (rRNA) genes. NORs are associated with proteins which can be visualized by a simple silver staining technique. As the number of NORs appears to reflect cell and nuclear activity its determination in benign, intermediate and malignant conditions could be of help in their differential diagnosis. In this study, we investigated 35 fibrohistiocytic tumors of the skin of benign, intermediate and malignant potential from 32 patients: 15 fibrous histiocytomas (FH), 5 FH with atypia (AFH), 7 atypical fibroxanthomas (AFX), 5 dermatofibrosarcoma protuberans (DFSP) and 3 malignant FH (MFH). A one‐step silver technique was used on formalin or Bouin fixed specimens. Ag‐NOR counts from benign conditions (FH, AFH) significantly differed from that of their intermediate‐risk (AFX, DFSP) and malignant (MFH) counterparts. Furthermore, in 2 cases (one AFX; one MFH) which twice recurred, Ag‐NOR counts steadily increased with time. However, a distinction could not be achieved between AFX and MFH. Although Ag‐NOR is a simple and valuable technique, it does not allow a definite distinction between malignant and intermediate processes, at least as far as fibrohistiocytic tumors of the skin are concerned.

Merkel cells do not express bullous pemphigoid antigen

Merkel cells (MC) are epithelial cells expressing cytokeratin-type intermediate filaments. They often are localized within the basal cell layer of the epidermis. Since basal cell layer keratinocytes synthetize basal membrane components, it was of interest to investigate whether or not MC could also do so. We used both double-labeling immunofluorescence and immune electron microscopy techniques with a panel of antibodies allowing the identification of MC as well as the staining of basal membrane zone components (including bullous pemphigoid antigen, laminin, type IV collagen and epidermolysis bullosa antigen). A specific loss of BP antigen expression was observed below all MC directly in contact with BMZ. This suggests that, although being an epithelial cell and in contrast to basal keratinocytes, MC does not secrete BP antigens.