Cheng S-T, Ke C-L K, Lee C-H, Wu C-S, Chen G-S, Hu S C-S
Department of Dermatology, Kaohsiung Medical University Hospital, and Faculty of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Br J Dermatol. 2009 Apr;160(4):801-9. doi: 10.1111/j.1365-2133.2008.08940.x. Epub 2008 Dec 1.
We found previously that the features of Kaposi's sarcoma (KS) under polarized dermoscopy are characterized by a bluish-reddish coloration, a scaly surface, small brown globules and, most distinctively, the multicoloured 'rainbow pattern'.
To evaluate the significance of the rainbow pattern on dermoscopy as a diagnostic feature in KS, and to demonstrate that it is associated with the unique vascular structure of the tumour.
More than 100 lesions from seven patients with histologically proven KS were examined with polarized light dermoscopy. Sixty-three patients with various other cutaneous vascular and nonvascular tumours were also examined. KS lesions exhibiting the rainbow pattern and KS lesions lacking the rainbow pattern on dermoscopy were excised, and dermoscopic features were compared with histopathological structures. The dermoscopic patterns of other vascular tumours were also compared with histological features. In addition, the changes in dermoscopic features and histological structures were assessed before and after surgical therapy in one patient with KS.
On the basis of evaluations with polarized dermoscopy, the rainbow pattern was found to be a highly specific dermoscopic feature for KS. Histology of KS lesions showing the rainbow pattern under polarized light dermoscopy demonstrated a vascular lumen-rich pattern of closely arranged 'back-to-back' vascular structures, whereas histology of KS lesions without the rainbow pattern showed a vascular lumen-poor pattern with vascular lumina separated further apart by intervening stromal and cellular tissue. Other vascular tumours did not exhibit the rainbow pattern and were characterized histologically by variably sized vascular structures separated by substantial amounts of stromal and cellular tissue. In one patient with KS, disappearance of the rainbow pattern was associated with obliteration of the vascular structure following surgical ablation therapy.
The rainbow pattern in KS is associated with the vascular lumen-rich histological subtype, is not manifest in the vascular lumen-poor subtype and disappears following total tumour removal. Therefore, the underlying structural arrangement of the vessels in KS may determine whether or not the rainbow pattern can be seen on polarized dermoscopy.
我们之前发现，偏振皮肤镜下卡波西肉瘤（KS）的特征表现为蓝红色泽、鳞屑样表面、小的褐色小球，最显著的是多彩的“彩虹图案”。
评估皮肤镜下彩虹图案作为KS诊断特征的意义，并证明其与肿瘤独特的血管结构相关。
对7例经组织学证实为KS的患者的100多个皮损进行偏振光皮肤镜检查。还对63例患有其他各种皮肤血管性和非血管性肿瘤的患者进行了检查。切除皮肤镜下呈现彩虹图案的KS皮损和缺乏彩虹图案的KS皮损，并将皮肤镜特征与组织病理学结构进行比较。还将其他血管性肿瘤的皮肤镜图案与组织学特征进行了比较。此外，对1例KS患者手术治疗前后的皮肤镜特征和组织结构变化进行了评估。
基于偏振皮肤镜评估，发现彩虹图案是KS高度特异的皮肤镜特征。偏振光皮肤镜下呈现彩虹图案的KS皮损组织学显示为血管腔丰富型，由紧密排列的“背靠背”血管结构组成，而无彩虹图案的KS皮损组织学显示为血管腔稀少型，血管腔被间质和细胞组织进一步分隔开。其他血管性肿瘤未呈现彩虹图案，组织学特征为大小不一的血管结构被大量间质和细胞组织分隔。在1例KS患者中，彩虹图案的消失与手术切除治疗后血管结构的闭塞有关。
KS中的彩虹图案与血管腔丰富的组织学亚型相关，在血管腔稀少的亚型中不明显，在肿瘤完全切除后消失。因此，KS中血管的潜在结构排列可能决定在偏振皮肤镜下是否能看到彩虹图案。
