Are dark-skinned people really protected from ultraviolet radiation?

BACKGROUND: Premature ageing of the skin (photoageing) results from the action of ultraviolet radiation (UVR) on skin. One of the histopathological findings of photoageing is the presence of solar elastosis in the dermis. Skin pigmentation is protective against UVR. AIM: To evaluate the presence of solar elastosis in dark-skinned people. METHODS: Normal facial skin biopsies of 147 dark-skinned and 140 light-skinned people were examined histopathologically for solar elastosis. The degree of solar elastosis was graded on a five-point scale by a panel of dermatopathologists blinded to patient demographics. RESULTS: There were 112 of 140 (80%) light-skinned and 50 of 147 (34%) dark-skinned patients with high-grade solar elastosis. In the dark-skinned patient group, high-grade solar elastosis was seen in 29 of 61 (47.5%) Hispanic and 5 of 49 (10.2%) African American subjects. CONCLUSIONS: Dark-skinned people are not completely protected from the effects of UVR.

Potassium permeability in -thalassemia minor red blood cells.

The intracellular content of K(+) in thalassemia minor red blood cells is markedly reduced after incubation in autologous serum for 24 hr at 37 degrees C. There is no compensatory increase in intracellular Na(+) concentration of the cell thus reduced. This change is due to an acquired increase in selective permeability of the membrane to K(+). This phenomenon follows the depletion of energy sources in the thalassemia minor cells but does not follow comparable depletion in normal cells. The loss of osmotically active intracellular contents probably accounts for the increased resistance of incubated thalassemia minor red blood cells to osmotic lysis.

Identification of PTEN mutations in metastatic melanoma specimens.

CONTEXT: PTEN, a tumour suppressor gene located on chromosome 10q23, develops somatic mutations in various tumours and tumour cell lines including brain, endometrium, prostate, breast, kidney, thyroid, liver, and melanoma. OBJECTIVES: To investigate the mutational profile of this gene further, as well as its role in tumour progression in melanoma. DESIGN, SETTINGS: We examined 21 metastatic melanoma samples for 10q23 allelic losses and PTEN sequence alterations. Additionally, we screened these samples for mutations in CDKN2A, a gene in which alterations are well documented in primary melanoma as well as in the germline of familial melanoma. RESULTS: Loss of heterozygosity (LOH) at 10q23 was observed in 33% (7/21) of the samples tested. We identified four sequence alterations in PTEN (19%) and two in CDKN2A (9.5%). Of interest, only one case showed mutations in both genes. CONCLUSIONS: These data support the notion that PTEN alterations occur in some metastatic melanomas, and that mutation of this gene plays a role in the progression of some forms of melanoma.

PTCH mutations in squamous cell carcinoma of the skin.

Ultraviolet light exposure is the major risk factor for the development of squamous cell carcinoma in Caucasians. Mutations in the tumor suppressor gene p53 have been identified in both squamous cell carcinomas and basal cell carcinomas. The human homolog of the Drosophila patched gene, has been shown to be mutated in sporadic basal cell carcinomas; however, mutations in the patched gene have not been found in squamous cell carcinoma. In this study, we screened a total of 20 squamous cell carcinoma samples for mutations in the patched gene. Using polymerase chain reaction-single strand conformation polymorphism as an initial screening method, we identified one non-sense mutation, two mis-sense mutations and three silent mutations in five squamous cell carcinoma samples. In one squamous cell carcinoma sample, we identified a tandem GG-->AA transitional change at nucleotide 3152 in exon 18 of the patched gene that resulted in a premature stop codon at codon 1051. The three squamous cell carcinoma samples containing non-sense and mis-sense mutations were isolated from individuals with histories of multiple basal cell carcinoma. Sequence analysis of the p53 gene in these five squamous cell carcinoma samples identified one CC-->TT and three C-->T ultraviolet-specific nucleotide changes. Our study provides evidence that the patched gene is mutated in squamous cell carcinoma from individuals with a history of multiple basal cell carcinoma. The identification of ultraviolet-specific nucleotide changes in both tumor suppressor genes supports the notion that ultraviolet exposure plays an important part in the development of squamous cell carcinoma.

Detection of human papillomavirus DNA in penile lesions histologically negative for condylomata. Analysis by in situ hybridization and the polymerase chain reaction.

The purpose of this study was to analyze penile lesions that lacked the histological features of condylomata for human papillomavirus (HPV) DNA. Most of these lesions were detected in men whose partners had an HPV-related lesion. Sequences homologous to HPV DNA were detected in 12 of 84 (14%) lesions using in situ hybridization analysis; nine of these lesions contained HPV 6 or 11. HPV DNA was found in 25 of 26 (96%) penile condylomata, all but two of which contained HPV 6 or 11. Using the highly sensitive polymerase chain reaction (PCR), we also detected HPV DNA in four of 20 (20%) of the penile lesions that lacked the histological features of condylomata negative for HPV by in situ analysis. Most of the lesions that were identifiable only after the application of an acetic acid solution were HPV negative when tested with either technique. We conclude that HPV DNA can be found in penile biopsy specimens that do not demonstrate the unequivocal histological features of condylomata but that the detection rate is much lower than for condylomata even when analyzing tissues in men at high risk for HPV-related lesions by PCR. This study underscores the need for caution when interpreting such tissues and the usefulness of in situ analysis for detecting assumed viral proliferation in noncondylomatous lesions.

Cutaneous leishmaniasis in Guatemala: comparison of diagnostic methods.

A comparison was made of methods used to diagnose suspected cutaneous leishmaniasis in Guatemala. The most sensitive method was a combination of thin smears made from superficial scrapings of the ulcers and inoculation of culture medium with either aspirates or scrapings. The diagnosis was confirmed in 252 (70%) of 362 patients. Ability to cultivate Leishmania was correlated with the concentration of amastigotes seen on thin smears. Leishmania were cultured in 42 (27%) of 153 patients with no amastigotes found in 400 oil-immersion fields and in 174 (83%) of 209 patients with at least 1 amastigote. No difference in diagnostic outcome was found when we compared smears or cultures taken from the center or the border of the ulcer or from an incision made tangential from the ulcer. We found no difference when we compared smears obtained with scalpels, capillary tubes, or dental broaches. The use of scrub brushes soaked in iodine neither decreased the rate of culturing parasites nor decreased contamination rates.

New world leishmaniasis. Serologic aids to diagnosis.

The increase in travel to endemic areas of South and Central America has led to an increase in the number of cases of cutaneous leishmaniasis diagnosed in the United States. Traditional methods of diagnosis for this disease include microscopical examination of infected tissue, culture of Leishmania on special media, and the leishmanin skin test. The present communication describes a case of cutaneous leishmaniasis and the difficulties that were encountered in diagnosis. New methods of serologic testing allow more prompt and accurate diagnosis.

Leukocytoclastic vasculitis in urticaria induced by ultraviolet irradiation.

A 35-year-old woman would develop urticarial lesions over one to four hours after irradiation with sunlight or artificial ultraviolet radiation. Lesions could persist for days before resolving. Although lesions were morphologically typical of solar urticaria, their evolution and resolution were both much slower than expected. Histologically, the lesions showed leukocytoclastic vasculitis. This unexpected finding suggests the possibility that there may be novel mechanisms involved in the pathogenesis of some cases of solar urticaria.

A distinctive variant of pernio. Clinical and histopathologic study of nine cases.

We describe here nine women who had similar distinctive clinical features that consisted of painful red-to-purple macules, papules, and plaques on the digits, predominantly on the toes. All patients reported that exposure to cold had preceded their symptoms. Histologic study demonstrated a lymphocytic vasculitis, characterized by lymphocytes infiltrating the walls of blood vessels in eight (88%) of nine lesions. This pattern of inflammation is different from the perivascular lymphocytic infiltrate that is common to lupus erythematosus, erythema multiforme, lymphocytic infiltration of the skin (Jessner), and drug eruptions. It also serves to distinguish the disorder from other clinical conditions resembling it, such as cellulitis, herpes simplex infection, and disseminated gonococcemia. To the best of our knowledge, this lymphocytic vasculitis has not been previously described as occurring in pernio. We believe the unique disorder that we are reporting is a common, but infrequently recognized, variant of pernio.

Treatment of dermatitis herpetiformis with colchicine.

Oral colchicine therapy was used successfully in the treatment of three patients with dermatitis herpetiformis, although the degree of disease control varied. The condition of a fourth patient did not improve. A trial of colchicine is suggested when conventional therapy with dapsone or sulfapyridine is contraindicated or when a gluten-free diet cannot be employed.

Acute myelomonocytic leukemia presenting as a benign-appearing cutaneous eruption.

Aleukemic leukemia cutis is a rare condition in which patients have skin lesions containing leukemic cells before evidence of leukemia can be detected in the peripheral blood. There are only 23 cases of this phenomenon documented in the English literature. We describe a 62-year-old woman who developed a diffuse, clinically benign-appearing cutaneous eruption, which histologically showed an atypical infiltrate of cells, 4 months before leukemic cells were found in her peripheral blood and the diagnosis of acute myelomonocytic leukemia was made by bone marrow aspiration. This case illustrates the difficulty in diagnosing leukemia cutis from examination of routine histologic sections and the importance of specialized marker studies in determining the cause of an atypical cellular infiltrate of the skin. It also illustrates how leukemia cutis can masquerade as a clinically benign-appearing cutaneous eruption in a seemingly healthy patient with normal blood parameters.

Clinical and histologic features of pityriasis lichenoides et varioliformis acuta in children.

Pityriasis lichenoides et varioliformis acuta (PLEVA) is commonly thought of as a disease of young adults, yet we identified five cases, involving patients who were 3, 5, 6, 8, and 11 years of age, among 13,000 consecutive specimens submitted to a general dermatopathology laboratory during a 15-week period. The clinical and histologic features of PLEVA in our cases were similar to those reported for adults, except that no lesions were observed on the scalp or mucous membranes of children. A high index of suspicion and biopsy specimens of suspected lesions are often needed to differentiate PLEVA from other papular and crusted eruptions seen in the pediatric age group. These include reactions to arthropods, Gianotti-Crosti syndrome, varicella, and erythema multiforme. Histologically, papular eczema and pityriasis rosea may be misdiagnosed as PLEVA.

Histologic evaluation of nail clippings for diagnosing onychomycosis.

Nail clippings from patients suspected of having onychomycosis were processed for histologic evaluation in the same manner as routine skin with the addition of a chitin-softening solution prior to processing. The sections were stained by the periodic acid-Schiff method and examined for fungal hyphae. The results were compared with the results of fungal cultures from the same nail. Our findings indicate that routine histopathologic analysis of the nail plate alone is a useful complementary method to fungal culture for diagnosing onychomycosis.

Photoallergic contact dermatitis to musk ambrette. Histopathologic features of photobiologic reactions observed in a persistent light reactor.

Studies concerning a patient with contact photosensitivity to musk ambrette, a commonly used fragrance, are reported. The patient had a persistent light reaction. The patient's history, clinical appearance, and phototest and photopatch test results are described. The observed patterns of these were identical to those previously noted in patients who had persistent light reactions after exposure to other photosensitizers such as the halogenated salicylanilides. The histopathologic findings in the phototest and photopatch test sites were those of an acute spongiotic dermatitis. No abnormal change was seen with ultraviolet A radiation exposure alone.

Intralesional corticosteroid therapy of chalazia.

Twelve adult patients with 17 chalazia underwent trial intralesional injection of triamcinolone acetonide. Seven chalazia resolved within two weeks after only one injection, and another six after two injections. Two lesions failed to respond to two injections, and two lesions responded to one injection, but either recurred or another lesion developed. Patients were satisfied with the procedure, which appears to be a safe, convenient, and effective altefnative to chalazion surgery.

Athlete's nodules. Treatment by surgical excision.

Athlete's nodules are connective tissue nevi of the collagen type (collagenomas) which appear as thick dermal masses at sites of chronic trauma. They have been described as occurring on the dorsum of the feet, knees, and knuckles of surfers, boxers and marble players. Recurrent minor blunt trauma and pressure are aetiological factors in this condition. We report a 54-year-old man with dermal nodules on the dorsal surface of his feet. These lesions initially appeared during his participation as a player on a high school football team. They were attributed to the chronic pressure of his high-laced athletic sneakers and frequent minor injuries to the involved areas. We describe the successful treatment of our patient's lesions by surgical excision. We also discuss the differential diagnosis and other therapeutic options for athlete's nodules.

Pathology of melanoma.

The biologic behavior of several common clinicopathologic types of melanoma is generally predictable by the depth of tumor invasion. However, some individuals have tumors that do no behave as predicted. These include what some authors have called borderline melanoma and minimal deviation melanoma as well as desmoplastic melanoma, thin superficial spreading melanoma with marked regression, and melanomas arising within some nevi. The reasons for the erratic behavior of these melanomas remains enigmatic.

Late reactions at Zyderm skin test sites.

We report on two patients in whom results of skin tests to injectable bovine collagen (Zyderm) became positive six weeks after administration. In one of these patients, the test was repeated, and showed identical result. It is recommended that Zyderm skin test sites be observed for at least six weeks before the test result is considered negative.

Shedding oral mucosa.

Four patients presented with asymptomatic gray-white oral mucosal tissues that sloughed and peeled away leaving a normal tissue base. This peeling phenomenon appeared unlike any known oral mucosal disease, although it somewhat resembled leukoedema and chemically irritated oral mucosa due to certain dentifrices and mouthwashes. Examination of biopsy tissue from three of the four cases along with stripped tissue from the fourth case revealed an intraepithelial cleft near the surface of each specimen. The linear cleft ran parallel to the epithelial surface. Foci of adjacent cells displayed intracellular edema, a feature commonly noted in leukoedema. There was evidence of neither acantholysis nor inflammation. The microscopic pattern was unlike the mucosal entities pemphigus vulgaris, mucosal pemphigoid, lichen planus, candidiasis, and mucosal biting. Although the authors questioned the patients in detail regarding all forms of mechanical and chemical trauma, including those from certain dentifrices and mouthwashes, they could not detect causative factors for these lesions.