Sun-protected Areas Research Articles

Basal cell carcinoma of the scalp resulting in spine metastasis in a black patient

Basal cell carcinoma (BCC), the most common skin cancer in the United States, is locally invasive but has a low risk of metastasis. BCC is rare in black patients but, regardless of racial origin, most BCC occurs on sun-exposed areas. We describe a 67-year-old black man with a large BCC on the hairy scalp, a relatively sun-protected area, that metastasized to the spine. To our knowledge, this is the first description of a black patient with development of metastatic BCC on an otherwise normal scalp.

Solar nevogenesis: A surrogate for predicting a rise in incidence of malignant melanoma because of ozone depletion

Several case-control studies have shown that the risk for development of a malignant melanoma (MM) isproportionalto the number ofmelanocytic neviborneby a person.1-3 Accordingto Hollyet al.,4 the risk of MM increases with the number of nevi: relative risksare 1.6(p =0.43) for 11 to 25 melanocytic nevi, 4.4 (p = 0.01) for 26 to 50 nevi, 5.4 (P =0.008) for 51 to 100nevi, and 9.8 (p = 0.001) for 1 to 5 dysplastic nevi and 6.3 (p =0.003) for 6 or more dysplastic nevi. The anatomic distribution of melanocytic nevi, favoring sun-exposed rather than sun-protected areas of the skin, implies their solar induction(i.e., solar nevogenesis).5-12 An increased numberof melanocytic nevi is seen in geographic regions of higher insolation.l3, 14 In addition, the number of nevi is increasedin immunosuppressed patientsl5,16 and UV irradiation causes cutaneous immunosuppression.l Melanocytic nevi are congenital or acquired. Most of the latter appearduring the first20 years of life. Acquired nevi, which are far more common than congenital nevi, can be subdivided into those induced bysun exposure (i.e., solarnevogenesis) and those lesscommonmelanocytic nevi that are not related to sun exposure.l ''

Solar nevogenesis: A surrogate for predicting a rise in incidence of malignant melanoma because of ozone depletion

Several case-control studies have shown that the risk for development of a malignant melanoma (MM) isproportionalto the number ofmelanocytic neviborneby a person.1-3 Accordingto Hollyet al.,4 the risk of MM increases with the number of nevi: relative risksare 1.6(p =0.43) for 11 to 25 melanocytic nevi, 4.4 (p = 0.01) for 26 to 50 nevi, 5.4 (P =0.008) for 51 to 100nevi, and 9.8 (p = 0.001) for 1 to 5 dysplastic nevi and 6.3 (p =0.003) for 6 or more dysplastic nevi. The anatomic distribution of melanocytic nevi, favoring sun-exposed rather than sun-protected areas of the skin, implies their solar induction(i.e., solar nevogenesis).5-12 An increased numberof melanocytic nevi is seen in geographic regions of higher insolation.l3, 14 In addition, the number of nevi is increasedin immunosuppressed patientsl5,16 and UV irradiation causes cutaneous immunosuppression.l" Melanocytic nevi are congenital or acquired. Most of the latter appearduring the first20 years of life. Acquired nevi, which are far more common than congenital nevi, can be subdivided into those induced bysun exposure (i.e., solarnevogenesis) and those lesscommonmelanocytic nevi that are not related to sun exposure.l ''

Characterization of the Skin In Vivo by High Resolution Magnetic Resonance Imaging: Water Behavior and Age-Related Effects

The age-related modifications of magnetic resonance imaging parameters in the skin have been studied in vivo. Modification of these parameters should provide important information about alterations in water structure and content in aged skin. Relaxation times, T1 and T2, and relative proton density, which corresponds to the mobile water proton fraction of tissues, have been measured on people under age 40 and over 70 on a sun-protected area. Results have confirmed in vivo skin layer differentiation through relaxation times performed in a previous study. Moreover, relative proton density quantification has shown that epidermal mobile water is at least twice as abundant as dermal mobile water. No significant age-related T1 and T2 modification could be established, basically because of a large dispersion of values. The main result concerns the upper part of dermis (about 200 microns in thickness) which contains significantly more mobile water protons in chronologic aged skin than in young adult skin. This increase has been related both to an increase of total water content in dermis with age and to an apparent decrease of collagen and proteoglycan content. Associated with alterations of their structure, this decrease reduces macromolecular-water interaction sites. This finding has to be compared with ultrasound evaluation of aged skin, which is characterized by modifications of the echogenicity, related to collagen bundles size and density, in the outer part of dermis, too. Both of the imaging techniques tend to consider the outer part of dermis as one of the privileged sites of skin aging.

Melanocytic naevi in sun-exposed and protected skin in melanoma patients and controls.

The possible link between exposure to ultraviolet light and naevus development was studied in 121 melanoma patients and 310 controls by comparing the number of naevi in a sun-exposed area on the back with that in a sun-protected area on the buttocks. Both patients and controls had a four-fold increase in the number of naevi in the exposed compared with the protected area, p less than 0.001. The difference in naevus count between the exposed and the protected area was larger in patients than in controls, p less than 0.001. Subjects with dysplastic naevi, melanoma patients as well as controls, had a larger difference in the number of naevi between the two areas than subjects without dysplastic naevi, p less than 0.001. These results support the idea that sunlight plays an important role in naevus development and may explain why a high naevus count is a risk marker for malignant melanoma.

Basal cell carcinoma

The common occurrence of basal cell carcinoma, especially in younger populations, has made it a major public health concern. It is the commonest malignancy affecting humans and is largely preventable. These facts have made it the focus of national attention and public education campaigns. Convincing epidemiologic data incriminate ultraviolet B (UVB) as a major etiologic factor, but there is also sufficient evidence that it is not the sole causative agent. Other agents implicated in the cause of basal cell cancers include long-term psoralen plus ultraviolet A (PUVA) therapy, grenz radiation, X-radiation, chronic arsenicism, preexisting lesions such as sebaceous nevus of Jadassohn and linear basal cell nevus, and genetic diseases such as xeroderma pigmentosum and nevoid basal cell carcinoma syndrome. Despite the fact that UVB has been recognized as a cause for several years, the pathophysiology of UVB-induced basal cell cancers has not been completely defined as yet. Other factors lead to the formation of basal cell cancers by different mechanisms, the pathophysiology of some being poorly understood. Recognition of the causes of basal cell cancers has led to the development of preventive measures such as photoprotection by avoidance of excessive sun exposure and use of sunscreens, limited use of grenz ray and x-ray therapy of the skin, monitoring of well water for its arsenic content, and prophylactic excision of nevus sebaceous when such a lesion is detected. Awareness of the increasing incidence has led to the development of screening programs for early detection of lesions also. Understanding of the biology of basal cell cancers continues to unfold with continuing investigation. Studies suggest that collagenase, derived from tumor stromal fibroblasts, plays a role in creating a path for tumor invasion by digesting collagen in the surrounding dermis. Fibronectin formed by tumor cells may be involved in tumor cell migration as well. Transplantation studies in animals have shown that immunologic phenomena play an important role in the biology of basal cell cancers. Human basal cell carcinoma has been recently transplanted successfully to immunosuppressed athymic mice. The human host allows growth of the cancer due to ultraviolet radiation (UVR)-induced immunosuppression. Immunologic abnormalities have been documented in patients with basal cell cancers. Immunologic deterioration may be a factor in the rare instance of metastatic basal cell cancer. Cognizance of the various common and uncommon clinical appearances of these neoplasms is important so that they can be recognized and treated effectively. The most common presentation is as a pearly papule or nodule with surface telangiectasias on a sun-exposed surface; other presentations include the pigmented, morpheaform, superficial, and fibroepithelioma of Pinkus types. Basal cell cancers may also be encountered on sun-protected areas. Familiarity with the logic behavior of the various types allows selection of the appropriate therapeutic modality. The histologic types of clinical import are the nodular, superficial, morpheaform, adenoid, and metatypical lesions. The latter three types invade local tissues more aggressively and consequently are best treated with Mohs surgery to ensure complete extirpation. Histologic confirmation of the diagnosis and definition of tumor type should be obtained prior to therapy. The six usual approaches for treatment are curettage and electrodesiccation, excision, cryosurgery, radiation therapy, topical chemotherapy, and Mohs micrographic surgery. The retinoids, etretinate and isotretinoin, have been useful in controlling the rate of appearance of basal cell cancers in patients with multiple basal cell cancers due to extensive sun exposure, xeroderma pigmentosum, and nevoid basal cell carcinoma syndrome. However, maintenance therapy is necessary for continued control. Systemic chemotherapy may be useful for reducing the size of inoperable tumors so that may become amenable to surgical resection, but this is seldom required. Indefinite follow-up and patient education are essential elements of management of basal cell carcinomas.

Elastophagocytosis: a non-specific reaction pattern associated with inflammatory processes in sun-protected skin.

Four cases characterized by primary inflammatory processes localized to sun-shielded skin were observed to have associated phagocytosis of elastic fibers by multinucleate histiocytic giant cells. These findings support the idea that this reaction pattern may occur non-specifically, at least in some instances, in sun-protected areas, as well as in sun-exposed skin as previously reported.

Deposits of immunoglobulins at the dermo-epidermal junction in chronic light-exposed skin: what is the value of the lupus band test?

Summary The effect of sunlight on the formation of functional deposits of immunoglobulins was studied using direct immunofluorescence in actinic keratosis as a model of a chronic, light-dependent dermatosis. Biopsies of lesions, of non-lesional tight-exposed (back of the hand) and of sun-protected (inside upper arm) areas from the same patient were examined. We could demonstrate functional deposits of IgM in most lesions of actinic keratosis (88%) and also in light-exposed non-lesional skin (80%), but only rarely complement or other immunoglobulins in lesional and non-lesional skin. The results of direct immunofluorescence in patients with active keratoses (25 cases) were qualitatively and semiquantitatively compared with functional deposits typical of chronic discoid lupus erythematosus (10 cases) by differentiating four types of immunofluorescence pattern (1-4). Stronger IF (type 3 or 4) was mainly, but not exclusively, seen in lupus erythematosus, type 1 or 2 often in actinic keratosis. Thus the examination of junctional IF in CDLE requires clear morphological criteria for the immunohistological diagnosis to prevent invalidation of the lupus hand test.

Relationship of nevocytic nevi to sun exposure in dysplastic nevus syndrome

In eighty consecutive patients who have the dysplastic nevus syndrome, the concentration of nevocytic nevi on the relatively sun-protected lateral thoracic area was compared to the concentration on the relatively sun-exposed areas of the anterior and posterior thorax. Nevocytic nevi in an area 7 X 20 cm were counted in each location. There was a total of 177 nevi on the lateral thorax (average, 2.2 nevi/person), 361 on the anterior thorax (average, 4.5 nevi/person), and 506 on the posterior thorax (average, 6.3 nevi/person). Men showed no significant difference in the number of nevi on the anterior and posterior thoracic areas, but women had fewer nevi on the anterior than on the posterior thoracic sites. These findings are consonant with the hypothesis that sunlight induces nevocytic nevi in patients who have the dysplastic nevus syndrome.

Clq deposits at the dermoepidermal junction: a marker discriminating for discoid and systemic lupus erythematosus.

Discoid lupus (DL) and systemic lupus erythematosus (SLE) patients have been comparatively evaluated for complement and immunoglobulin deposits at the dermoepidermal junction (DEJ) by immunofluorescence (IF). When IF was positive, Clq deposits were quasi-constantly found in SLE patients with or without skin lesions (90%), while Clq was found in only 29% of the DL patients. Of the 42 DL patients followed-up to at least 2 years, 4 have eventually evolved a systemic disease. In these 4, neither cryoglobulinemia nor significant titers of ANA had been found at the time of presentation. Only 1 of these 4 patients had initially circulating immune complexes (P.E.G) and a positive IF in a normal sunprotected area. Clq deposits at the DEJ were present in all these 4. Of the remaining 38 DL patients, none has progressed to SLE: 8 had had significant titers of ANA, 5 had had circulating immune complexes, and 3 others had had cryoglobulinemia. Thus Clq deposits in DL cases are associated with a relatively high incidence of eventual systemic disease. Taken together, these data suggest that Clq deposits in skin may be a marker for systemic lupus.