認識Kaposi肉瘤

　　Kaposi肉瘤屬於血管的惡性腫瘤，一般認為與病毒感染有關或基因病變有關。事實表明，卡波西肉瘤與HHV-8感染密切相關。HHV-8可通過唾液、性交、血液製品、器官移植傳播。 　　Kaposi肉瘤(KaposiS sarcoma，KS)又稱為多發性特發性出血性肉瘤(multiple idiopathic hemorrhagic sarcoma)，屬於血管的惡性腫瘤，最早在1872年由匈牙利皮膚科醫師Moritz Kaposi所描述。病因未明，一般認為與病毒感染有關或基因表達異常有關。流行病學調查及在肉瘤組織中分離出HHV-8，事實表明，KS與HHV-8感染密切相關，HHV-8也稱“卡波西肉瘤相關皰疹病毒”(KSHV)。HHV-8可通過唾液、性交、血液製品、器官移植傳播。在AIDS associated KaposiS sarcoma患者中，其血清學陽性率是100％(The disease is named after Moritz Kaposi, a Hungarian dermatologist who first described the symptoms in 1872. Research over the next century suggested that KS, like some other forms of cancer, might be caused by a virus or genertic factors)。除HHV-8外，有研究提示發生卡波西肉瘤的病人具有HIA-DR5等位基因者的比例較高，說明卡波西肉瘤發生可能與遺傳有關。
　　臨床可分為歐洲型、非洲型、移植相關型和愛滋病相關型4型。典型表現為皮膚黏膜、內臟、淋巴組織的單一或多發病變。預後變化很大，某些患者可以長期病情穩定。 　　關於Kaposi肉瘤細胞的來源，可能是起自於間質前體細胞衍化來的血管，或是來自發育異常的內皮細胞(Despite its name, it is generally not considered a true sarcoma, which is a tumor arising from mesenchymal tissue 。KS actually arises as a cancer of lymphatic endothelium and forms vascular channels that fill with blood cells, giving the tumor its characteristic bruise-like appearance)。In Vitro研究結果指出，HIV-1反向啟動基因(TAT)及其產物Tat proteins可刺激Kaposi肉瘤細胞生長，並促使oncostatin-M和IL-6 receptors的表達。然而，Kaposi肉瘤細胞分泌IL-6，與IL-6 receptors結合後，會進一步刺激腫瘤細胞增值，也刺激其他間質細胞增殖，並且誘導血管生長。 　　根據研究，歐洲及北美地區，卡波西肉瘤相關性皰疹病毒(Kaposis sarcoma- associated herpesvirus，KSHV)可以經由接吻的唾液來傳播的。但在同性戀或雙性戀性伴侶之間深吻(deep kissing)，將KSHV有更高的傳播速率。另外，KSHV 也可藉由器官移植或輸血方式將病毒帶入體內。因此，完善器官移植前或輸血前病毒篩查，將可避免KSHV醫源性傳播。(In Europe and North America KSHV is transmitted through saliva. Thus, kissing is a theoretical risk factor for transmission although transmission between heterosexuals appears to be rare. Higher rates of transmission among gay and bisexual men has been attributed to "deep kissing" sexual partners with KSHV. KSHV is transmissible during organ transplantation and to a lesser extent through blood transfusion. Testing for the virus before these procedures is likely to effectively limit iatrogenic transmission) 　　KS各型並無明顯差異，其特點是腫瘤內由梭形細胞(Spindle cells)、網狀纖維和膠原纖維、血管等組成。梭形細胞的核大小不一和核多形性。

• 早期的組織象呈現肉芽組織性炎症，伴有血管新生和淋巴管形成。肉芽組織中出現向血管腔突出的內皮細胞，並有RBC滲出(RBC leaking)到周圍組織及含鐵血黃素(Hemosiderin)，使腫瘤外觀看起來顏色深暗，這對KS早期診斷意義極大。
• 晚期有廣泛的結締組織增生，與一般肉瘤不易區分，可做免疫組化來明確診斷。

(KS lesions contain tumor cells with a characteristic abnormal elongated shape, called spindle cells. The tumor is highly vascular, containing abnormally dense and irregular blood vessels, which leak red blood cells into the surrounding tissue and give the tumor its dark color. Inflammation around the tumor may produce swelling and pain)

　　關於卡波西肉瘤的分型、臨床症狀與體徵、診斷方式、鑑別診斷與治療等各方面，我們將在臨床醫學教室為各位講解，敬請留意！

Kaposi肉瘤、卡波西肉瘤、血管惡性腫瘤、基因病變、病毒感染、HHV-8、人類疱疹病毒、基礎醫學資訊館