Jag Bhawan

Light microscopic, immunohistochemical, and ultrastructural alterations in patients with melasma.

Despite new technologies, few studies have assessed the histologic alterations in patients with melasma. Using current technologies, the present study was designed to re-evaluate the light microscopic, immunohistochemical, and ultrastructural changes of the hyperpigmented and adjacent normal skin of patients with melasma. Twenty-one patients were included in this study. Two millimeter punch biopsies were taken from the hyperpigmented and adjacent normal skin of the face. The integrity of the epidermis and dermis was assessed by light microscopy, computer-assisted image analysis, immunohistochemistry, and electron microscopy. Stains included hematoxylin-eosin and Fontana-Masson for melanin detection. Immunostaining was performed using Mel-5 antibody and CD1a antibody as markers for melanin and Langerhans cells, respectively.However, mild lymphohistiocytic infiltrates were present in 75% of the hyperpigmented areas. The areas of hyperpigmentation showed increased deposition of melanin in the epidermis and dermis of all cases. There was a statistically significant increase in the content of epidermal melanin. There were no quantitative increases in melanocytes in the hyperpigmented areas of skin. However, the melanocytes in the hyperpigmented areas were larger, intensely stained cells with very prominent dendrites. Electron microscopy revealed more melanosomes in keratinocytes, melanocytes, and dendrites in the involved skin in comparison to the uninvolved skin. The results of this study suggest that melasma is a consequence of specific hyperfunctional melanocytes that cause excessive melanin deposition in the epidermis and dermis.

Photoaging versus intrinsic aging: a morphologic assessment of facial skin

Histologic studies have become increasingly important in recognizing morphologic differences in photoaged versus intrinsically aged skin. Earlier histologic studies have attempted to evaluate these changes by examining anatomical sites which are not comparable, such as face and buttocks. As part of a multicenter study, we have quantitatively examined a panel of 16 histologic features in baseline facial skin biopsies from 158 women with moderate to severe photodamage. When compared to the postauricular area (photo protected), biopsies of the crows feet area (photo exposed) had a twofold increase in melanocytes and a statistically significant increase in melanocytic atypia (p<.0001) and epidermal melanin (p< .0001). Other epidermal changes included reduced epidermal thickness (p<.01), more compact stratum corneum (p<.0001) and increased granular layer thickness (p<.0001) in the crows feet skin. There was increased solar elastosis (p<.0001), dermal elastic tissue (p<.0001), melanophages (p<.0001), perivascular inflammation (p<.05) and perifollicular fibrosis (p<.01) but no change in the number of mast cells or dermal mucin in the photo exposed skin. Our data document quantitative differences in photoaged versus intrinsically aged facial skin and provides the groundwork for future studies to evaluate the efficacy of new treatments for photoaged skin.

Effect of beta-carotene supplementation on the human sunburn reaction.

Abstract Beta‐carotene, a quencher of excited species such as singlet oxygen and free radicals, has been reported to protect against cutaneous photodamage, including sunburn acutely and photocarcinogenesis chronically. The present double blind placebo‐controlled study examines the ef‐tect of beta‐carotene supplementation on the human sunburn response and specifically on the induction of sunburn cells at the time of peak reaction intensity (24 h) after a single solar simulated light exposure 3 times the individually determined minimal erythema dose (MED). Administered orally either as a single 120 mg dose to dietarily restricted subjects or for 23 d as a daily 90 mg supplement to subjects on standard diets, beta‐carotene increased plasma and skin levels of beta‐carotene compared to both pretreatment levels and placebo‐treated controls, but provided no clinically or histologically detectable protection against a 3 MED sunburn reaction. Thus, these data suggest that oral beta‐carotene supplementation is unlikely to modify the severity of cutaneous photodamage in normal individuals to a clinically meaningful degree.

Mixed Merkel cell carcinoma and squamous cell carcinoma of the skin

Four mixed Merkel cell and squamous cell carcinomas of the skin are described. The patients ranged in age from 74 to 90 years and demonstrated or had a history of previous ultraviolet or infrared damage to the skin, manifested by basal cell carcinoma, squamous cell carcinoma, actinic keratoses, solar elastosis, and erythema ab igne. Light microscopic examination of all 4 cases revealed invasive neoplasms consisting of 2 distinct but admixed cell types. The predominant cell type was consistent with Merkel cell carcinoma and was characterized by scant cytoplasm, a small dark polygonal nucleus with granular chromatin, a high mitotic rate, and cytokeratin 20 positivity. In each case, the Merkel cell component merged with a cytokeratin 20 negative squamous component characterized by abundant eosinophilic cytoplasm, intercellular bridges, and keratinization with focal squamous pearl formation. Immunohistochemical staining patterns were consistent with the usual pattern for that cell type; transitional cells were not demonstrated. The intimate admixture of the 2 antigenically different neoplastic cell types, and common etiologic role of ultraviolet and possibly infrared damage, lend support to the theory that some Merkel cell carcinomas and squamous cell carcinomas may arise from a pluripotent epidermal stem cell.

p75 nerve growth factor receptor staining helps identify desmoplastic and neurotropic melanoma

Melanoma is a malignant tumor with a varied histologic appearance. Melanoma composed of spindle cells may include desmoplastic and neurotropic melanoma. The histologic diagnosis of desmoplastic and neurotropic melanoma can be difficult. Although S100 protein stains a majority of these melanomas, die staining may be weak or focal. HMB‐45, a more specific marker of melanoma, is frequently negative in desmoplastic and neurotropic melanoma.

Cultured epidermal autografts and allografts: A study of differentiation and allograft survival

Cultured epidermal sheets were examined before and at various times after grafting on skin ulcer beds. Before grafting, the sheet consisted of four to five layers of keratinocytes with incomplete differentiation. Ten days after grafting, graft recipient sites showed compact hyperkeratosis, a normal-appearing epidermis, and a flat dermoepidermal junction. At 6 months, the stratum corneum had a basket-weave appearance but the dermoepidermal junction remained flat. Monoclonal antibodies to keratins 14 and 10 showed normal basal and suprabasal localization, respectively. Electron microscopy showed a normal basement membrane with anchoring fibrils. LH7:2, a monoclonal antibody that binds to the type VII collagen molecule, stained the dermoepidermal junction in all biopsy specimens. AE-1, an antibody that stains suprabasal cells in hyperproliferative skin, was expressed suprabasally for up to 12 weeks after healing (16 weeks after grafting), but expression was confined to the basal layer at 18 weeks after healing (6 months after grafting). Anti-involucrin staining was found in the deeper layers of the epidermis up to 12 weeks after healing (16 weeks after grafting) but had receded to a normal distribution in upper spinous and granular layers at 18 weeks (6 months after grafting). Overall, the histologic patterns observed in recipient sites during the first 4 months after grafting resembled those observed for 10 to 14 days in newly healed epidermis and in hyperproliferative states such as psoriasis. In four sex-mismatched graft sites, specimens were reacted with a biotinylated probe to the Y chromosome by in situ hybridization. Lack of Y chromosome-positive cells suggested that host keratinocytes had replaced the allografts. Multilocus DNA analysis in one patient confirmed this observation. Our data suggest that an altered state of epithelial maturation persists for several months after culture grafting, with restoration of the normal pattern by 6 months. No differences were detected between autografted and allografted sites.

Burn scar carcinoma. Diagnosis and management.

background. The term Marjolin ulcer is now synonymous with malignant transformation of chronic ulcers, sinus tracts, and burn scars. objective. To illustrate the importance of incisional or excisional biopsies in cases of suspected burn scar carcinoma. methods. Case report and review of the literature. results. Multiple punch biopsies were negative while a complete excision revealed the diagnosis of squamous cell carcinoma. conclusion. Because of the focal nature of malignant change in burn scars, incisional or excisional biopsy should be performed.

Lhx2 differentially regulates Sox9, Tcf4 and Lgr5 in hair follicle stem cells to promote epidermal regeneration after injury

The Lhx2 transcription factor plays essential roles in morphogenesis and patterning of ectodermal derivatives as well as in controlling stem cell activity. Here, we show that during murine skin morphogenesis, Lhx2 is expressed in the hair follicle (HF) buds, whereas in postnatal telogen HFs Lhx2+ cells reside in the stem cell-enriched epithelial compartments (bulge, secondary hair germ) and co-express selected stem cell markers (Sox9, Tcf4 and Lgr5). Remarkably, Lhx2+ cells represent the vast majority of cells in the bulge and secondary hair germ that proliferate in response to skin injury. This is functionally important, as wound re-epithelization is significantly retarded in heterozygous Lhx2 knockout (+/–) mice, whereas anagen onset in the HFs located closely to the wound is accelerated compared with wild-type mice. Cell proliferation in the bulge and the number of Sox9+ and Tcf4+ cells in the HFs closely adjacent to the wound in Lhx2+/– mice are decreased in comparison with wild-type controls, whereas expression of Lgr5 and cell proliferation in the secondary hair germ are increased. Furthermore, acceleration of wound-induced anagen development in Lhx2+/– mice is inhibited by administration of Lgr5 siRNA. Finally, Chip-on-chip/ChIP-qPCR and reporter assay analyses identified Sox9, Tcf4 and Lgr5 as direct Lhx2 targets in keratinocytes. These data strongly suggest that Lhx2 positively regulates Sox9 and Tcf4 in the bulge cells, and promotes wound re-epithelization, whereas it simultaneously negatively regulates Lgr5 in the secondary hair germ and inhibits HF cycling. Thus, Lhx2 operates as an important regulator of epithelial stem cell activity in the skin response to injury.

Lymphangiogenesis and angiogenesis in non‐phymatous rosacea

Background:  Our study evaluated the expression of vascular endothelial growth factor (VEGF), CD31 and D2‐40 in involved and uninvolved skin of 18 patients with rosacea.

Systematic underreporting of cutaneous malignant melanoma in Massachusetts: Possible implications for national incidence figures

An independent tabulation of incidence of cutaneous malignant melanoma in Massachusetts indicates that 12% and perhaps as many as 19% of new cases of cutaneous malignant melanoma in Massachusetts are not recorded in the Massachusetts Cancer Registry, significantly more than the expected 5% (p = 0.0001). The increasing number of nonhospital medical settings in which melanomas can be diagnosed and/or treated appears to account for this discrepancy. We suspect that these findings in Massachusetts also apply to cancer reporting systems in other regions of the United States. We suggest that the true incidence of cutaneous malignant melanoma in Massachusetts, and perhaps in the United States, may be significantly higher than reported.