Detection of HHV-8 in Pyogenic Granuloma-like Kaposi Sarcoma

Abstract

Kaposi sarcoma (KS) is a low-grade vascular neoplasm associated with human herpesvirus-8 (HHV-8) infection. Clinically, lesions commence as blue-red macules that may develop into plaques and eventually into nodules. The histologic appearance spans a broad spectrum and varies with the stage of the lesion. At each stage, KS has significant morphologic overlap with other vasoproliferative lesions. Recently, we encountered 6 KS tumors that histologically mimicked pyogenic granuloma (PG), a common benign vascular tumor of the skin that usually does not figure in the histologic differential diagnosis of KS. We stained 6 PG-like KS and 28 PGs with a mouse monoclonal antibody (13B10) against HHV-8 latent nuclear antigen-1 (LNA-1) to determine the utility of immunoperoxidase staining in distinguishing KS from PG. All 6 PG-like KS demonstrated nuclear staining for HHV-8 LNA-1. No staining was identified in any of the 28 PGs. Histologic criteria often used to differentiate between these two entities were not helpful in our cases. The only distinguishing feature was the presence or absence of HHV-8 LNA-1 staining. The presence of HHV-8 LNA-1 nuclear staining seems to be a specific marker for KS when comparing PGs and PG-like KS. Immunoperoxidase staining for HHV-8 LNA-1 is a useful diagnostic tool in this setting.

Kaposi Sarcoma with Abscessing Clinicopathologic Morphology

“…Apart from heightened awareness and recognition of the changing face of KS in the AIDS era, diagnostic confirmation has also been facilitated by the relative recent discovery of Human herpesvirus-8 (HHV8), also labelled KS-associated herpes virus, as the viral etiopathogenesis of KS [17]. This has facilitated improved understanding of KS and therapeutic possibilities and distinction from diagnostic masqueraders [17][18][19][20][21][22][23]. The commercial availability of HHV-8 LANA-1 immunohistochemical antibodies and HHV8 PCR studies has enabled the diagnostic confirmation of KS in challenging histodiagnostic settings [19][20][21][22].…”

Pyogenic Granuloma‐Like Kaposi's Sarcoma

“…Importantly, HHV-8 LNA-1 immunoreactivity has not been reported in pyogenic granuloma 7. Previously reported cases of pyogenic granuloma-like Kaposi sarcoma have described varying degrees of positivity for HHV-8 LNA-1.…”

Histological Subgroups in Classic Kaposi Sarcoma

“…PBS ile y›kand› ve protein blokaj› sonras›nda primer antikor ile ile oda s›cakl›¤›nda 1 saat inkübe edildi. S›ras›yla sekonder antikor, streptavidin peroksidaz kompleksi ve renklendirmek icin 6,[9][10][11][12][13][14][15][16] . En s›k görülen his- …”

“…Bu grupta yer alan olgular›n %26,4'ü makül, %37,6's› plak ve %36's› nodüler evre lezyonlard›r. Serimizde olgular›n %17,2'si histopatolojik özellikleri aç›s›n-dan literatürde tan›mlanan alt tipler ile uyum göstermekte-dir 6,[9][10][11][12][13][14][15][16] . En s›k görülen histolojik alt tip lenfanjiyektatik varyant (%7,3) olup, bunu s›ras›yla büllöz (%2,6), lenfanjiyom benzeri (%2,6), intravasküler (%2) ve piyojenik granülom benzeri (%2) varyantlar izlemektedir.…”

“…Bu olgularda HHV8 immün reaksiyonunun gösterilmesi tan›y› destekler 25,26 . Urguhart ve ark., bu histolojik alt tipin iyi s›-n›rl›, epidermisin yakal›k tarz›nda lezyonu çevreledi¤i, iyi geliflmifl kapillerlerin eksofitik proliferasyonu olarak tan›mla-maktad›r 16 . Ek olarak, bu alt tipte piyojenik granüloma benzer olarak epidermiste ülserasyon ve dermiste nötrofil infiltrasyonu izlenmektedir 6 .…”