Đang chuẩn bị liên kết để tải về tài liệu:
PATHOLOGY OF VASCULAR SKIN LESIONS - PART 8

Tại các khu vực khác, các mạch máu xâm nhập vào giữa các bó collagen của lớp bì, cho sự xuất hiện rằng họ đang "mổ xẻ" các chất nền. Trong những trường hợp hiếm hoi, các mạch máu mới được thành lập hình thành các cụm tương tự như hemangiomas nhỏ | 224 Sangueza and Requena Pathology of Vascular Skin Lesions Fig. 7. AIDS-associated Kaposi s sarcoma involving the oral mucosa. adnexae and blood vessels producing the so-called promontory sign 71 Fig. 9 . In other areas the blood vessels infiltrate between collagen bundles of the dermis giving the appearance that they are dissecting the stroma. In rare instances the newly formed blood vessels form clusters that resemble small hemangiomas 71 74 . The inflammatory cells present are predominantly lymphocytes and plasma cells. The presence of plasma cells around newly formed irregular blood vessels is a helpful clue in the histopathologic diagnosis of the patch stage of Kaposi s sarcoma 71 . Another characteristic feature of patch stage lesions of Kaposi s sarcoma is the presence of scattered necrotic endothelial cells a feature that has been emphasized at both the conventional microscopy 77 and ultrastructural level 41 . Hemosiderin-laden macrophages are another feature frequently found in early lesions of Kaposi s sarcoma. The histopathologic features just described for the patch lesions can also be seen in clinically normal areas of skin in patients who have Kaposi s sarcoma elsewhere which supports the notion of the diffuseness of the process from its inception 79 80 . Plaque lesions of Kaposi s sarcoma tend to involve the entire dermis and even the upper part of the subcutaneous fat. At this stage there is an increased number of spindle cells arranged in short fascicles between collagen bundles centered around proliferating vascular channels. The spindle cells line irregularly shaped slit-like vascular spaces that contain isolated erythrocytes. They display minimal or no atypia with only a few to no mitotic figures. Chapter 9 Malignant Neoplasms 225 A Fig. 8. Histopathologic features of patch stage Kaposi s sarcoma. A At scanning magnification the lesions consists of increased numbers of jagged spaces at different levels of the dermis. B Higher magnification .