Ishihara Yasushi, Saida Toshiaki, Miyazaki Atsushi, Koga Hiroshi, Taniguchi Ayako, Tsuchida Tetsuya, Toyama Miki, Ohara Kuniaki
Department of Dermatology, Shinshu University School of Medicine, Matsumoto, Japan.
Am J Dermatopathol. 2006 Feb;28(1):21-7. doi: 10.1097/01.dad.0000187931.05030.a0.
In non-white populations, acral skin is the most prevalent site of malignant melanoma. Early melanomas of this anatomic site are often misdiagnosed as melanocytic nevi, which are not uncommon on acral skin. In fact, clinical and/or histopathological features of melanocytic nevi occasionally mimic those of early acral melanoma and vice versa, and thus differentiation of early acral melanoma from melanocytic nevus is sometimes very difficult for clinicians as well as for histopathologists. Our dermoscopic investigation has revealed that the parallel ridge pattern, a band-like pigmentation on the ridges of the skin markings, is highly specific to malignant melanoma in situ on acral volar skin. In the present study, we reviewed 22 acral melanocytic lesions that showed the parallel ridge pattern on dermoscopy but had very subtle clinical and/or histopathological presentations. We diagnosed 20 of them as early melanoma in situ by careful histopathological examination, which revealed histopathological features very similar to those seen in macular portions of overt acral melanoma, but fundamentally different from features found in melanocytic nevi on acral skin. In correspondence with their dermoscopic pattern, in these early lesions of acral melanomas, proliferation of solitary arranged melanocytes was mainly detected in the crista profunda intermedia, the epidermal rete ridge underlying the ridge of the skin marking. The two remaining lesions were diagnosed as possible cases of acquired melanocytic nevus because of the formation of well-demarcated nests of melanocytes in the epidermal rete ridges. We propose that a finding of preferential proliferation of solitary arranged melanocytes in the crista profunda intermedia is an important clue for the histopathological diagnosis of early phases of acral melanoma.
在非白人人群中，肢端皮肤是恶性黑色素瘤最常见的部位。该解剖部位的早期黑色素瘤常被误诊为黑素细胞痣，而黑素细胞痣在肢端皮肤上并不少见。事实上，黑素细胞痣的临床和/或组织病理学特征偶尔会与早期肢端黑色素瘤相似，反之亦然，因此对于临床医生和组织病理学家来说，区分早期肢端黑色素瘤和黑素细胞痣有时非常困难。我们的皮肤镜检查发现，平行嵴模式，即皮肤纹理嵴上的带状色素沉着，对掌侧肢端原位恶性黑色素瘤具有高度特异性。在本研究中，我们回顾了22例皮肤镜检查显示平行嵴模式但临床和/或组织病理学表现非常细微的肢端黑素细胞病变。通过仔细的组织病理学检查，我们将其中20例诊断为早期原位黑色素瘤，其组织病理学特征与明显的肢端黑色素瘤黄斑部分所见非常相似，但与肢端皮肤黑素细胞痣的特征根本不同。与它们的皮肤镜模式一致，在这些早期肢端黑色素瘤病变中，主要在中间深层嵴（皮肤纹理嵴下方的表皮 rete 嵴）中检测到单个排列的黑素细胞增殖。其余两个病变被诊断为后天性黑素细胞痣的可能病例，因为在表皮 rete 嵴中形成了界限清楚的黑素细胞巢。我们提出，在中间深层嵴中发现单个排列的黑素细胞优先增殖是肢端黑色素瘤早期组织病理学诊断的重要线索。
