Fig. 10.30 Kaposisarcoma.(A)Characteristiccoalescentcutaneousred-purplemaculesandplaques.(B)Histologicviewofthenodularstage,demonstratingsheetsofplump,proliferatingspindlecellsandslitlikevascularspaces.(Courtesy of Christopher D.M. Fletcher, MD, Brigham and Women’s Hospital, Boston, Massachusetts.) http://ebooksmedicine.net
Epithelioid hemangioendothelioma is a tumor of adults arising in association with mediumto large-sized veins. The clinical course is highly variable. While excision is curative in a majority of the cases, up to 40% of the tumors recur; 20% to 30% eventually metastasize, and 15% of patients die of their tumors.
Angiosarcomas are malignant endothelial neoplasms ranging from highly differentiated tumors resembling hemangiomas to wildly anaplastic lesions. Older adults are more commonly affected, without gender predilection; lesions can occur at any site, but most often involve the skin, soft tissue, breast, and liver. Clinically, angiosarcomas are aggressive tumors that invade locally and metastasize. Current 5-year survival rates are only about 30%.
Angiosarcomas can arise in the setting of lymphedema, classically in the ipsilateral upper extremity several years after radical mastectomy (i.e., with lymph node resection) for breast cancer. In such instances, the tumor presumably arises from lymphatic vessels (lymphangiosarcoma). Angiosarcomas can also be induced by radiation and rarely are associated with long-term (years) indwelling foreign bodies (e.g., catheters).
Hepatic angiosarcomas are associated with certain carcinogens, including arsenical pesticides and polyvinyl chloride (one of the best known examples of human chemical carcinogenesis). Multiple years typically transpire between exposure and subsequent tumor development.
MORPHOLOGYIntheskin,angiosarcomasbeginassmall,sharplydemarcated,asymptomaticrednodules.Moreadvancedlesionsarelarge,fleshyred-tantogray-whitemasses(
Fig.10.31A )withmarginsthatblendimperceptiblywithsurroundingstructures.Necrosisandhemorrhagearecommon.
Onmicroscopicexamination,theextentofdifferentiationisextremelyvariable,rangingfromplumpatypicalECsthatformvascularchannels(
Fig.10.31B )toundifferentiatedspindlecelltumorswithoutdiscerniblebloodvessels.TheECorigincanbedemonstratedinthepoorlydifferentiatedtumorsbystainingfortheECmarkersCD31andvonWillebrandfactor(
Fig.10.31C
Vascularectasiasarenotneoplasms,butratherdilationsofexistingvessels.
Vascularneoplasmscanderivefromeitherbloodvesselsorlymphatics,andcanbecomposedofECs(e.g.,hemangioma,lymphangioma,angiosarcoma)orothercellsofthevascularwall(e.g.,glomustumor).
Mostvasculartumorsarebenign(e.g.,hemangioma);somehaveanintermediate,locallyaggressivebehavior(e.g.,Kaposisarcoma);andothersarehighlymalignant(e.g.,angiosarcoma).
Benigntumorstypicallyformobviousvascularchannelslinedbynormal-appearingECs.Malignanttumorsmoreoftenaresolidandcellular,exhibitcytologicatypia,andlackwell-definedvessels.