Becker's nevus or Becker's melanosis is a distinct clinical entity in which epimal thickening may be minimal and hairiness and pigmentation obvious. 1Ne report a case of 14-year-old female suffering from Beckers melanosis with multiple and extensive skin lesions. The electron microscope revealed that the melanocytes were bulky with increased melanogenesis and an increased number of melanosomes was found in the keratinocytes. In addition, a large number of melanosomes were seen individually in the keratinocytes.
Adolescent ; Female ; Humans ; Keratinocytes ; Melanocytes ; Melanosis ; Melanosomes ; Nevus* ; Pigmentation ; Skin

No abstract available.
Eczema ; Inflammation ; Melanocytes ; Nevus

No abstract available.
Hair* ; Melanocytes* ; Nevus, Halo*

No abstract available.
Humans* ; Melanocytes* ; Tretinoin*

Agminated lentigines may be defind as a circumscribed grouping of small pigmented macules arranged in a small or large group, often in a segmental pattern, each macule consisting of a lentiginous epidermal proliferation of melanocytes. We report five cases of agminated lentigines in otherwise healthy persons. Histologic exarnination of the pigmented lesion revealed findings consistent with lentigo simplex.
Humans ; Lentigo* ; Melanocytes

BACKGROUND: The growth of cells is closely related to components in a culture medium. There are many reports about cellular characteristics of melanocytes grown in a PMA-contained medium. However, only a few reports have been studied by using a physiologic mitogens-contained medium. To understand melanocyte in vivo, it is necessary to know the cellular biology of melanocytes grown in a physiologic mitogens-contained medium. OBJECTIVE: To investigate any differences between melanocytes grown in phorbol 12-myristate 13-acetate(PMA)-contained medium and in physiologic mitogens-contained medium. METHOD: We examined morphology, number and melanin contents of cultured human melanocytes grown in a PMA-contained medium and physiologic mitogens-, such as bFGF, ET-1 and a a-MSH contained medium. Result : The results are summarized as follows : 1. There were no significant morphologic differences between cells in PMA-contained medium and in physiologic mitogens-contained medium. 2. The number of melanocytes were significantly more numerous in PMA-contained medium on the 2nd day (p<0.05), but significantly less numerous in the same medium on the 6th day (p<0.05). So, the proliferation rate of melanocytes in PMA-contained medium became lower than in physiologic mitogens-contained medium as time went by. 3. Melanocytes grown in PMA-contained medium had significantly increased melanin contents regardless of the time (p<0.05). Conclusion : The proliferation of melanocytes was better in physiologic mitogens-contained medium, the melanization was higher in melanocytes of PMA-contained medium.
Humans* ; Melanins ; Melanocytes*

No abstract available.
Hypopigmentation* ; Melanins* ; Melanocytes* ; Melanosis*

BACKGROUND: There have been only a few electron microscopic studies after laser treatment of pigmented skin lesions. OBJECTIVE: The purpose was to investigate the pathologic, immunohistochemical, and electron microscopic changes following Q-switched alexandrite laser treatment of pigmented skin lesions. METHODS: Three patients with acquired bilateral nevus of Ota-like macules, and 2 patients with cafeau lait macule were irradiated with Q-switched alexandrite laser. Forty biopsies were taken before and immediately after laser treatment. Hematoxylin-eosin, Fontana-Masson, and gp100 staining were performed for the evaluation of the histopathologic and immunohistochemical findings of the specimens. Electron microscopic findings were also evaluated. RESULTS: Histopathologically, suprabasilar separations were observed immediately after laser treatment. Vacuolar alterations of pigment-containing cells were frequently found in the epidermis and/or in the dermis. Fontana-Masson and gp100 staining positivity changed to negative or decreased in the epidermis immediately after laser treatment, while they changed to negative in the dermis. Ultrastructurally, epidermal pigment-containing cells frequently showed severe vacuolar changes in the cytoplasm, pyknotic nuclei, and vacuolated and/or fragmented melanosomes immediately after laser treatment. Dermal melanocytes frequently revealed vacuolated and/or fragmented melanosomes immediately after laser treatment. CONCLUSION: Histopathologic, immunohistochemical, and electron microscopic examination of pigmented skin lesions immediately after Q-switched alexandrite laser treatment demonstrated vacuolated or fragmented melanosomes and vacuolar alteration of pigment-containing cells in the epidermis and/or in the dermis, which suggested selective photothermolysis of melanosomes.
Biopsy ; Cytoplasm ; Dermis ; Epidermis ; Humans ; Lasers, Solid-State* ; Melanocytes ; Melanosomes ; Nevus ; Skin*

BACKGROUND: Transfer of melanosomes from melanocytes to the neighboring keratinocytes is a critical step in normal pigmentation. However, the mechanism of melanosome transfer and the regulation of pigmentation by the keratinocyte-melanocyte interactions are not well understood. It has recently been identified that keratinocytes use Foxn1 (transcription factor) to recruit melanocytes and induce their own pigmentation. OBJECTIVE: The purpose of this study was to assess the expression of Foxn1 in hypopigmentary disorders (vitiligo, pityriasis alba (P. alba) and postinflammatory hypopigmentation (PIHo)) and hyperpigmentary disorders (melasma, caf?-au-lait macule (CALM) and postinflammatory hyperpigmentation (PIHer)). METHODS: Immunohistochemical staining was performed on the formalin-fixed, paraffin-embedded tissue sections of hypopigmentary and hyperpigmentary disorders using anti-Foxn1 antibody with an avidin-biotin peroxidase complex procedure. The intraepidermal melanin pigments were examined in all the lesions by Fontana-Masson staining. RESULTS: We found a significantly lower Foxn1 expression (p<0.05) and less intraepidermal melanin pigments (p< 0.01) in the hypopigmentary disorders as compared to that of the hyperpigmentary disorders. In the hypopigmentary disorders such as vitiligo, P. alba and PIHo, the expression of Foxn1 was decreased in the order named. In thehyperpigmentary disorders such as CALM, PIHer and melasma, the expression of Foxn1 was increased in the order named. CONCLUSION: The intraepidermal Foxn1 expression and melanin pigments in PIHer, PIHo and melasma showed a positive correlation, but there was no statistically significant. Our findings suggest that the expression of Foxn1 might be associated with the pathogenesis of three pigment disorders (PIHo, PIHer, melasma). We consider that inflammatory mediators might interact with the intraepidermal Foxn1 expression in PIHo, PIHer and melasma, resulting in an abnormality of the mechanism of melanosome transfer. Further studies are warranted to elucidate the role of the Foxn1 expression in the pathogenesis of pigment disorders.
Hyperpigmentation ; Hypopigmentation ; Keratinocytes ; Melanins ; Melanocytes ; Melanosis ; Melanosomes ; Peroxidase ; Pigmentation ; Pityriasis ; Vitiligo

We report two familial cases of reticulate acropigmentation of kitamura in 20-year-old male and 29-year-old female patients in which reticualte, brownish, slightly depressed pigmentation developed on acral parts of extremities and subsequently extended proximally. Characteristic pits and breaks on palms and soles were noted. Histologic findings revealed epidermal atrophy and enlongation of rete ridges with large amounts of melanin. Electron microscopic findings showed increased melanogenesis in melanocytes and numerous melanosomes and melanosome complex in keratinocytes.
Adult ; Atrophy ; Extremities ; Female ; Humans ; Keratinocytes ; Male ; Melanins ; Melanocytes ; Melanosomes ; Pigmentation ; Young Adult