The Emerging Histopathologic Diagnostic Challenges of Kaposi Sarcoma in the Acquired Immunodeficiency Syndrome Era

Research Article

Austin J HIV/AIDS Res. 2016; 3(1): 1020.

The Emerging Histopathologic Diagnostic Challenges of Kaposi Sarcoma in the Acquired Immunodeficiency Syndrome Era

Ramdial PK1*, Miles E1 and Pillay B2

1Department of Anatomical Pathology, National Health Laboratory Service & School of Laboratory Medicine & Medical Sciences, University of KwaZulu Natal, Durban, KwaZulu Natal, South Africa

2Department of Vascular/Endovascular Surgery, Nelson R Mandela School of Medicine, University of KwaZulu Natal, Durban, KwaZulu Natal, South Africa

*Corresponding author: PK Ramdial, Department of Anatomical Pathology, Level 3, Laboratory Building, Inkosi Albert Luthuli Central Hospital, 800 Vusi Mzimela Road, Mayville, 4058, Durban, KwaZulu-Natal, South Africa

Received: January 01, 2016; Accepted: February 11, 2016; Published: February 15, 2016


The acquired immunodeficiency syndrome (AIDS) not only catapulted Kaposi Sarcoma (KS) as the commonest AIDS-associated malignancy, but also introduced a wider histomorphological spectrum and an expanded range of diagnostic mimicry and pitfalls. A tissue diagnosis of KS is necessary because of the clinical differential diagnoses, especially in the skin where overlapping features between diseases are visually appreciated. However, the histopathological diagnostic challenges facing the pathologist are not fully recognized. This review highlights the histomorphological challenges that impact the diagnosis of KS in the context of the mimicry of/by traditional KS variants, increased recognition of uncommon variants, emergent histomorphological variants, impact of co-lesional, co-morbid infections and treatment and procedure-related diagnostic challenges.

Keywords: HIV; AIDS; Kaposi’s sarcoma; Pathology; Challenges


AIDS: Acquired Immunodeficiency Syndrome; AIDS-KS: Acquired Immunodeficiency Syndrome-Associated Kaposi Sarcoma; EBV: Epstein Barr Virus; HAART: Highly Active Anti-Retroviral Therapy; HHV8-LNA-1: Human Herpesvirus 8-Latent Nuclear Antigen-1; HIV: Human Immunodeficiency Virus; KS: Kaposi Sarcoma; LLKS: Lymphangioma-Like Kaposi Sarcoma


Kaposi Sarcoma (KS), a multicentric disorder of endothelial origin, is the most frequently observed Human Immunodeficiency Virus (HIV)/Acquired Immunodeficiency syndrome (AIDS)- associated malignancy [1]. Although mucocutaneous disease occurs more commonly than visceral disease, the microscopic morphological landscape is characterized by a spindle-shaped cellular neoplastic infiltrate in a richly-vascularized background, a mononuclear cell-rich inflammatory infiltrate, erythrocyte extravasation and edema [2]. The cutaneous spectrum, traditionally encompassing patch, plaque and nodular stages, are well-recognized entities [3]. However, the HIV/AIDS era has introduced an expanded spectrum of histomorphological variants [4,5,6]. Furthermore, the microscopic features of KS lesions maybe impacted by co-morbid, concomitant immunosuppressive diseases [7-13], and Highly Active Anti-Retroviral Therapy (HAART)-induced flares and regression. Finally, challenges arising from secondary AIDS-associated diseases such as lymphedema and biopsy factors may impact the diagnostic recognition of KS [14,15].

This review highlights the histomorphological diagnostic challenges of KS in the HIV/AIDS era in the context of the:

Mimickers of Traditional KS Variants

Although there is a decrease in AIDS-associated KS (AIDS-KS) following HAART implementation in developed countries, this is not the case in developing countries where the incidence of KS continues to increase (3). Apart from the rapid lesional evolution and atypical predilection for the trunk and mucosal surfaces in AIDS patients, visceral involvement also occurs more commonly [16]. The established nodular stage of AIDS-KS does not pose diagnostic dilemmas (Figures 1A-D), but a spindle cell-rich angiosarcoma, pyogenic granuloma and bacillary angiomatosis (Figures 1E-F) may be challenging. While these mimickers lack Human herpes virus 8-latent nuclear antigen-1 (HHV8-LNA-1) immunopositivity, KS lacks the cellular pleomorphism of angiosarcoma, argyrophilic bacillary clusters of bacillary angiomatosis (Figure 1F) and the prominent lobulation and intervascular septa of pyogenic granuloma. The aneurysmal pseudovascular foci, inflammatory component and hemosiderin pigment in aneurysmal fibrous histiocytoma may pose a pitfall but the admixture of foam cells, variable fibrosis and peripheral collagen compartmentalization and HHV8-LNA-1 immunonegativity will enable KS diagnosis [16]. A lobular architecture, intralesional thrombi and absence of eosinophilic globules help differentiate KS from epithelioid hemangioendothelioma [16].