Faculty Bibliography

Melasma is an acquired brown hypermelanosis of the face. Although it is thought that melasma is associated with multiple etiologic factors (pregnancy, gastric, racial, and endocrine), one of the primary causes of its exacerbation appears to be exposure to sunlight. Three patterns of melasma are recognized clinically: (1) a centrofacial pattern, (2) a malar pattern, and (3) a mandibular pattern. Examination of patients with Wood's light (320--400 nm) is useful in classifying the specific type of melasma in correlation with the localization of pigment granules (melanosomes) in the epidermis and dermis. Four types of melasma are described on the basis of Wood's light examination: (1) an epidermal type, (2) a dermal type, (3) a mixed type, and (4) a fourth type, described in patients of dark complexion, in which the lesions, for lack of contrast, are not discernible on Wood's light examination, perhaps due to the increased number of melanosomes in the normal skin of black individuals. Light, histochemical, and electron microscopic studies revealed an increase in number and activity of type-specific melanocytes which appeared to be engaged in increased formation, melanization, and transfer of pigment granules (melanosomes) to the epidermis as well as to the dermis. The melanocyte seems to undergo a functional alteration brought about by a combination of multiple factors, including persistent sun exposure, hormonal factors, and genetic predisposition.

We report four cases of actinic reticuloid, including the first case ever reported in a woman. We have concluded that not all the patients are persistent light reactors and that the histologic presentation can be quite variable, in some cases extremely difficult to differentiate from a cutaneous lymphoma. Phototesting studies in incriminate the long UV and/or visible light range. The duration of the disease in these cases suggests a benign process which can be included among the cutaneous pseudomalignancies. Further cytoimmunological studies may incriminate the interaction of T-lymphocytes in the pathogenesis of the condition.

Diffuse fasciitis (DF) shares clinical and pathologic features with systemic (SS) and localized scleroderma. The distinct pathologic feature in DF is involvement of the deep fascia, but it is not known if these changes consistently occur in SS. In this study, ten patients with SS underwent deep biopsies for evaluation of the fascia. All cases showed typical dermal histologic findings of scleroderma, and five cases showed thickening and fibrosis of the fascia. This study provides evidence that fascial involvement is not distinctive of DF but may occur in SS. It appears that thickening of the fascia is another morphologic feature shared between DF and SS.

A case of acral lentiginous malignant melanoma is presented in detailed clinical and histologic features because it showed an unusually large vesicle in which there were findings consistent with an exaggerated focal acantholytic dyskeratosis.

It has long been claimed that a specific histologic diagnosis of mycosis fungoides cannot be made in the premycotic' or 'eczematous' (patch) stage of the disease. Indeed, the histologic features of the premycotic lesions were constantly said to be those of 'chronic non-specific dermatitis.' We studied 46 biopsy specimens of patch lesions from patients in whom mycosis fungoides was unequivocally established by clinical events (i.e., concurrence or later development of typical plaque and/or nodular lesions) and indubitable histologic findings. We divided patch lesions into early nonatrophic patches and late atrophic ones. The early patches are considered to be evolving lesions of mycosis fungoides, whereas late patches represent resolving plaques of the disease. On the basis of this study, we concluded that histologic diagnosis can be made with near certainty in patch lesions of the disease. We found that the critical feature for histologic diagnosis of early and late patch lesions of mycosis fungoides is the presence of an increased number of mononuclear cells distributed singly or in small collections within an epidermis devoid of spongiotic microvesiculation. Other important features are lacunae surrounding intraepidermal mononuclear cells which gives them the appearance of 'haloed cells.' A sparse infiltrate of mononuclear cells is present around the blood vessels of the superficial, and sometimes the deep, vascular plexus. Atypical mononuclear cells are not necessary for the diagnosis of early patch lesions of mycosis fungoides, but they are found commonly in late patch lesions. Late atrophic patches show a thinned epidermis, loss of the usual configuration between rete ridges and dermal papillae, and coarse collagen throughout a thickened papillary dermis

A case of angiolymphoid hyperplasia with eosinophilia mimicking multiple cylindromas (turban tumor) is presented in detailed clinical and histologic features, and the literature on the condition is reviewed.

A 40 year-old female with multiple dermatofibromas (82) associated with Dermatofibrosarcoma Protuberans is presented. Although of a common fibroblastic origin, these lesions are considered independent. Their presence in the same patient is considered of interest.