Hindawi Publishing Corporation Case Reports in Medicine Volume 2013, Article ID 959812, 6 pages http://dx.doi.org/10.1155/2013/959812 Case Report Cavernous Hemangioma-Like Kaposi Sarcoma: Histomorphologic Features and Differential Diagnosis Nilüfer Onak Kandemir, 1 Figen Barut, 1 Banu DoLan Gün, 1 Nilgün Solak Tekin, 2 Sevinç Hallaç Keser, 3 and Fükrü OLuz Özdamar 1 1 Department of Pathology, Faculty of Medicine, B¨ ulent Ecevit University, 67100 Zonguldak, Turkey 2 Department of Dermatology, Faculty of Medicine, B¨ ulent Ecevit University, 67100 Zonguldak, Turkey 3 Department of Pathology, Dr. L¨ utf Kırdar Training and Research Hospital, Istanbul, Turkey Correspondence should be addressed to Nil¨ ufer Onak Kandemir; niluferkandemir@yahoo.com Received 6 May 2013; Revised 12 August 2013; Accepted 19 August 2013 Academic Editor: Jochen Utikal Copyright © 2013 Nil¨ ufer Onak Kandemir et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Aim. Cavernous hemangioma-like Kaposi sarcoma is a rare morphologic type of Kaposi sarcoma. So far there are no cases in the literature defning the histological features of this morphologic spectrum in detail. In this study we presented two classical- type cutaneous Kaposi sarcoma cases with histologic fndings resembling cavernous hemangioma in company with clinical and histopathological data. Cases. One hundred and eighty-fve classical-type cutaneous Kaposi sarcoma lesions in 79 patients were assessed retrospectively in terms of histopathological features. Findings of two cases showing features of cavernous hemangioma- like Kaposi sarcoma whose clinical data could be accessed were presented in accompany with the literature data. Both cases were detected to have bluish-purple, protruded, irregularly bordered cutaneous lesions. Histopathological examination revealed a lesion formed by cavernous hemangioma-like vascular structures organized in a lobular pattern that became dilated and flled with blood. Typical histological fndings of early-stage KS, consisting of mononuclear infammation, extravasated erythrocytes, and a few immature vascular structures in superfcial dermis, were observed. All cases were serologically HIV-1 negative. A positive reaction with HHV-8, CD31, CD34, and D2-40 monoclonal antibodies was identifed at both cavernous hemangioma-like areas and in immature vascular structures. Results. Cavernous hemangioma-like Kaposi sarcoma is a rare Kaposi sarcoma variant presenting with diagnostic challenges, that may be confused with hemangioma. As characteristic morphological features may not be observed in every case, it is important for diagnostic purposes to show immunohistochemical HHV-8 positivity in this variant. 1. Introduction Kaposi sarcoma (KS) is a rare vascular lesion with four diferent epidemiological forms (classical, African (endemic), iatrogenic, and AIDS related) caused by human herpes virus- 8 (HHV-8) [1]. It may have various clinical and histopatho- logical features. More than 10 histological subtypes has been defned so far (e.g., anaplastic, lymphangioma-like, and micronodular KS) [2, 3]. While clinical appearance of lesions is diferent from usual type KS in some subtypes (e.g., bullous, verrucous, and ecchymotic KS), most histological subtypes do not have a prominent discriminatory clinical feature [1– 7]. Despite being variable by lesion stage, some character- istic fndings are important in histopathological diagnosis. Among these are immature vascular formations intersecting collagen to form clef- or mesh-like patterns and spindle cells that are considered to be the main neoplastic component. Hyaline globules, hemosiderin pigment, and lymphoplasma- cytic infammatory cells frequently accompany neoplastic vascular structures [1, 8]. In KS spindle cells and neoplastic vascular structures react positively with endothelial markers (e.g., CD31, CD34, and D2-40) [1]. Te most important point in the diagnosis of KS is to show HHV-8 immunopositivity supporting histological fndings in the neoplastic component [9–11]. Since they are considerably rare, we discussed two cases of classical-type cutaneous KS exhibiting cavernous hemangioma-like features in company with clinical and histopathological fndings and stressed the importance of HHV-8 immunoreactivity in diferential diagnosis of these lesions.