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Novel morphological study of solar lentigines by immunohistochemical and electron microscopic evaluation
Author(s) -
Watanabe Tessin,
Tahira Makoto,
Morino Shinichi,
Horie Takashi,
Adachi Koji,
Tsutsumi Reiko,
Yamada Nanako,
Yoshida Yuich,
Yamamoto Osamu
Publication year - 2013
Publication title -
the journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 65
eISSN - 1346-8138
pISSN - 0385-2407
DOI - 10.1111/1346-8138.12165
Subject(s) - pathology , immunohistochemistry , dermis , epidermis (zoology) , cytokeratin , dermoepidermal junction , melanocyte , basal (medicine) , biology , keratinocyte , dermatology , chemistry , medicine , anatomy , melanoma , in vitro , biochemistry , genetics , insulin , endocrinology
Solar lentigines ( SL ) are hyperpigmented lesions generally seen in elderly people. Their pathogenesis has not been completely elucidated. We examined 75 cases of SL using routine histopathology and immunohistochemistry. In addition, seven cases were evaluated by electron microscopy. Histopathologically, we observed vacuolar changes in the dermoepidermal junction in 85% of the cases. Dermal melanophages were seen in 77% of the cases. The immunohistochemical expression rates in the epidermis for cytokeratin ( CK )15, CK 14, CK 10, p63 and nestin were 76%, 100%, 100%, 100% and 17%, respectively. In 58 cases showing dermal melanophages, expression rates of CD 163 and factor XIIIa on melanophages were 79% and 83%, respectively. Double positivity for both proteins was identified in 44 cases (75%). Ultrastructurally, vacuolar structures were seen in the cytoplasm of basal cells and upper dermis in all cases examined. We observed elimination processes of damaged basal keratinocytes, which were probably produced by ultraviolet ( UV ) irradiation, into the papillary dermis. The segregated damaged cell bodies containing melanin granules seemed to be phagocytosed by poorly immunostimulatory macrophages labeled immunohistochemically by CD 163 and factor X IIIa, contributing to prolonged pigmentation of SL . In addition, repeated basal keratinocyte damages may be in association with altered CK and p63 expression patterns in the constituent cells of SL .