Patel Kalyani R, Chernock Rebecca, Lewis James S, Raptis Constantine A, Al Gilani Maha, Dehner Louis P
Lauren V Ackerman Laboratory of Surgical Pathology, Department of Pathology and Immunology, Washington University in St Louis, St Louis, MO, 63108, USA.
Head Neck Pathol. 2013 Dec;7(4):404-8. doi: 10.1007/s12105-013-0441-4. Epub 2013 May 7.
Congenital melanocytic nevus (CMN) is a melanocytic proliferation that has its onset at birth or shortly thereafter and shows characteristic histopathologic features including symmetric proliferation of benign melanocytes, extension of nevus cells into the deep reticular dermis and subcutis, maturation of melanocytes with descent, tracking of melanocytes around and within adnexal structures, vessels, or nerves and splaying of collagen bundles by nevus cells arranged in single rows or cords. We report the case of a 34 year old previously healthy woman who presented with a progressively enlarging soft tissue mass in the right neck and back adjacent to a medium sized CMN. Magnetic resonance imaging showed multiple lipomatous masses within the soft tissues of the posterior superficial neck. Subsequent excision of the soft tissue mass showed a well circumscribed lipomatous lesion with diffuse infiltration by benign appearing melanocytes within the fat lobules. Excision of the mass was not accompanied by overlying skin and, thus, posed a diagnostic challenge. Sudden increase in the size of a CMN is worrisome for the development of a melanoma, however, this lesion lacked significant cytologic atypia and mitotic figures, and had a low proliferative index by Ki-67 immunohistochemistry. This case serves to illustrate the initial diagnostic dilemma as well as the plasticity of the neural crest cells.
先天性黑素细胞痣（CMN）是一种黑素细胞增殖性病变，出生时或出生后不久发病，具有特征性组织病理学特征，包括良性黑素细胞对称增殖、痣细胞延伸至深层网状真皮和皮下组织、黑素细胞随下移而成熟、黑素细胞围绕并侵入附属器结构、血管或神经，以及痣细胞呈单行或索状排列使胶原束分离。我们报告一例34岁既往健康女性，其右侧颈部和背部靠近一个中等大小CMN处出现一个逐渐增大的软组织肿块。磁共振成像显示颈后部浅表软组织内有多个脂肪瘤样肿块。随后切除的软组织肿块显示为边界清楚的脂肪瘤样病变，脂肪小叶内有良性外观的黑素细胞弥漫浸润。肿块切除未包括覆盖其上的皮肤，因此带来了诊断挑战。CMN大小突然增加令人担忧黑色素瘤的发生，然而，该病变缺乏明显的细胞异型性和核分裂象，且Ki-67免疫组化显示增殖指数较低。该病例说明了最初的诊断困境以及神经嵴细胞的可塑性。
