Breza Thomas S, Magro Cynthia M
College of Medicine, The Ohio State University, Columbus, OH 43210-1218, USA.
J Cutan Pathol. 2005 Nov;32(10):685-9. doi: 10.1111/j.0303-6987.2005.00367.x.
The histological diagnosis of malignant melanoma can be challenging. Immunohistochemical techniques may define a critical role in certain cases, specifically in establishing a primary diagnosis of melanoma. CD34 is a hemopoietic stem cell antigen expressed in bone marrow and endothelial cells, and may also be expressed in vascular and spindle cell tumors; it is generally negative in malignant melanoma.
An 83-year-old white female presented with a 3-4 mm area on her right upper back, which had been present for several years. Histologic sections showed a polypoid distortion by sheets and nodules of transformed amelanotic melanocytes lying in intimate apposition to an attenuated epidermis without a concomitant radial growth phase. Tumor cells were extensively S-100 and CD34 positive and showed focal immunoreactivity with melan-A and HMB-45.
We present a case of malignant melanoma of nodular subtype, which strongly expressed CD34. The spectrum of abnormal phenotypes in malignant melanoma is reviewed, and a possible explanation for the presence of CD34 is discussed. This case demonstrates the potential of malignant melanoma to express CD34, defining an infrequently recognized aberrant phenotype. Whether or not expression of this marker is associated with a more aggressive clinical course remains to be determined.
恶性黑色素瘤的组织学诊断可能具有挑战性。免疫组织化学技术在某些情况下可能发挥关键作用，特别是在确立黑色素瘤的初步诊断方面。CD34是一种在骨髓和内皮细胞中表达的造血干细胞抗原，也可能在血管和梭形细胞瘤中表达；它在恶性黑色素瘤中通常为阴性。
一名83岁的白人女性，右上背部有一个3 - 4毫米大小的区域，已存在数年。组织学切片显示为息肉样变形，由成片和结节状的无色素性黑色素细胞组成，紧密贴附于变薄的表皮，无伴随的放射状生长期。肿瘤细胞广泛S - 100和CD34阳性，并对黑色素A和HMB - 45呈局灶性免疫反应。
我们报告一例结节型恶性黑色素瘤病例，该病例强烈表达CD34。回顾了恶性黑色素瘤异常表型的范围，并讨论了CD34存在的可能解释。该病例证明了恶性黑色素瘤表达CD34的可能性，定义了一种较少被认识到的异常表型。这种标志物的表达是否与更具侵袭性的临床病程相关仍有待确定。
