Detection of HHV-8 in pyogenic granuloma-like Kaposi sarcoma

An exophytic red-purple nodule on the hip

A 35-year-old man with Fitzpatrick skin type IV, born in Brazil, presented to the dermatology clinic with a 3-month history of an asymptomatic growth on the left hip. He reported no prior history of trauma.

Human Herpesvirus 8 (HHV-8) Staining: A Savior in Early Kaposi Sarcoma

Kaposi sarcoma (KS) is a low-grade vascular neoplasm associated with human herpesvirus 8 (HHV-8) infection. The disease has various phases, and the morphology of the lesion may vary, especially in the early course of the disease, where the morphological features may not be even suggestive of Kaposi sarcoma. The authors take this opportunity to report a case of Kaposi sarcoma where the diagnosis was established because of HHV-8 staining rather than its histopathological features.

Angiosarcoma-like Kaposi Sarcoma: A Distinctive Histomorphologic Variant Representing an Important Diagnostic Pitfall

Kaposi sarcoma (KS) is a rare low-grade angioproliferative neoplasm associated with human herpesvirus 8 (HHV-8) infection with multiple clinical subtypes and varying histopathologic patterns. Histologically, many different variants of KS have been reported, yet all can be difficult to recognize and must be differentiated from other vascular tumors. In this report, we studied fourteen cases of a newly described variant of KS reminiscent of a well-differentiated angiosarcoma (angiosarcoma-like KS). All cases showed a diffuse, ill-defined infiltrative dermal-based lesion composed of numerous anastomosing vascular channels of varying caliber lined by a single layer of endothelium with minimal pleomorphism. The vascular proliferation ramified through the dermis and dissected the collagen bundles along with infiltration into the subcutaneous fat and around skin appendages. All cases showed expression of vascular markers (CD31, CD34, and ERG) and were positive for HHV-8. None showed the classic histopathology associated with KS. Without clinical guidance these tumors can be difficult to recognize as KS, creating significant diagnostic challenges. Our study expands on a rare histologic variant of KS that ought to be considered in the differential diagnosis of any cutaneous well-differentiated angiosarcoma. Awareness of this variant of KS is of important for proper diagnosis and management of these patients; thus, careful attention to the histomorphology and clinical history can help lead the pathologist to the correct diagnosis.

Pyogenic granuloma-like Kaposi sarcoma presenting in an HIV-negative man who has sex with men

A 36-year-old immunocompetent man who have sex with men first presented to the plastics team with an ulcerating lesion on his left first toe. The lesion was suggestive of pyogenic granuloma (PG) clinically and histologically. Two years later, the same patient presented to the dermatology clinic with a new erythematous lesion with intermittent bleeding on the left second toe. Clinically, this lesion was suggestive of another PG. However, the histology of the skin curettage revealed part of a PG merging with an atypical spindle cell proliferation with characteristic 'sieve-like' appearance in keeping with Kaposi sarcoma. This was confirmed with human herpesvirus-8 immunohistochemistry staining. PG-like Kaposi sarcoma is an uncommon variant of Kaposi sarcoma. Often not considered clinically or histologically, a deep skin biopsy is essential to establish the right diagnosis. Our case highlights the need to consider Kaposi sarcoma as a differential diagnosis in all patients, including HIV-negative individuals, presenting with PG-like lesions.

D2-40 negative pyogenic granuloma-like Kaposi's sarcoma: Diagnostic features and histogenetic hypothesis of an uncommon skin tumor in HIV-negative patients

Pyogenic granuloma-like Kaposi's sarcoma (PGLKS) is a recently described skin tumor showing features both of pyogenic granuloma (PG) and Kaposi's sarcoma (KS). The differential diagnosis is often challenging. We reviewed a series of 50 PG and 23 Ks located on distal extremities with the aid of an immunohistochemical panel comprising CD34, CD31, FVIII, SMA, D2-40, HHV8. After revision, 6/50 PG lesions previously diagnosed as PG, showed positive immunostaining for LNA1-HHV8 and focal positivity for CD31 and FVIII in the endothelial cells of the proliferating vessels, with some SMA positive pericytes. D2-40, a marker of lymphatic endothelium positive in KS, stained negatively. These lesions were renamed PGLKS. Of note, in our series, PGLKS represented the only form of KS localized in the hand; all the patients were HIV-negative, older than PG patients, with a prevalence for male gender. PGLKS and PG need a different management and a follow-up is advisable for PGLKS, as for the other variants of KS. To date, D2-40 negative immunostaining has not yet been reported in PGLKS and should not lead to a misdiagnosis of PG. The morphological similarities with PG and the immunohistochemical findings, showing a defective phenotype of the neoplastic cells, suggest a histogenetic hypothesis in which D2-40 negative PGLKS could represent an early stage of HHV8 infection of a pre-existing PG, whose vessels loose progressively their blood vascular markers but have not still acquired the lymphatic ones.

Anogenital Lesions: Kaposi's Sarcoma and Its Mimicks

Kaposi's sarcoma (KS) is a low-grade vascular neoplasm associated with human herpes virus-8 (HHV-8) infection, and, in the epidemic form, with the human immunodeficiency virus (HIV). Although HHV-8 is present in all body fluids and is sexually transmitted, there are surprisingly few reports of anogenital KS. Clinically, especially in HIV/KS endemic areas, dark stained skin patches or nodules are prone to misdiagnosis, especially in dark-skinned individuals. Therefore, a biopsy is recommended. The histologic appearance spans a broad spectrum of KS and non-KS lesions; therefore, the final diagnosis should be confirmed by HHV-8 immunohistochemistry. We report a series of 36 anogenital biopsies from a group of 16 documented HIV-positive patients; in 20 the HIV serostatus was unknown. There were ten KS (five in HIV-positive patients), and 26 non-KS (11 in HIV-positive subjects) lesions. In the era of HIV/AIDS, anogenital lesions may be the first manifestation of KS in immunocompromised individuals and should be biopsied. The histological diagnosis should be confirmed by HHV-8 immunohistochemistry.

Clinicopathological Proficiency in the Diagnosis of Kaposi's Sarcoma

Background. The prevalence of Kaposi's sarcoma (KS), an AIDS-defining illness, has increased in parallel with the HIV/AIDS epidemic. The presence of violaceous skin lesions should raise suspicion of KS. However, especially on dark skin, KS mimics a variety of non-KS skin conditions. Histologically, there is a wide range of expressions of KS and a large number of mimickers. For all these reasons, a HHV-8 immunohistochemically biopsy-proven diagnosis of KS should be the gold standard. Methods. Prospective study of 490 consecutive skin biopsies from the general community in the Limpopo Province of South Africa, from April 2010 through December 2011. Results. The clinical discordance rate (over-/underdiagnosis of KS) was 30.5%; the histological discordance rate was 9.2%. Conclusion. Because of the magnitude of diagnostic error, both clinical and histological, all clinical lesions suspicious of KS should be biopsied and HHV-8 LAN-1 immunophenotyped.

Unique histologic variants of cutaneous Kaposi sarcoma

BACKGROUND

Kaposi sarcoma (KS) is a low-grade angioproliferative neoplasm derived from lymphatic endothelium. Lesions progress from early patch stage into plaques that ultimately form tumor nodules. Several histological variants of KS have been described. The aim of this study is to describe 5 new histopathologic variants of cutaneous KS.

METHOD

Skin biopsy material submitted to a South African dermatopathology practice diagnostic of KS was reviewed. Formalin-fixed, paraffin-embedded tissue was routinely processed and stained with hematoxylin and eosin. Confirmatory immunohistochemical stains included CD31 and latent nuclear antigen-1 (human herpesvirus 8).

RESULTS

All biopsies were procured from HIV-positive patients with a clinical diagnosis of cutaneous KS tumor. Five distinct histologic KS variants, not previously well characterized in the literature, were identified including glomeruloid KS, telangiectatic KS, ecchymotic KS, KS with myoid nodules, and pigmented KS. Tumor cells in all of these variants were immunoreactive for CD31 and latent nuclear antigen-1.

CONCLUSIONS

These unique cases highlight the ability of KS to exhibit variable histomorphology. Their clinical significance requires further study. Dermatopathologists should be aware of these newly described variants to avoid the potential for their misdiagnosis.

Dermatopathological challenges in the human immunodeficiency virus and acquired immunodeficiency syndrome era

The histopathological assessment of cutaneous lesions is critical to the definitive diagnosis of many human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome-associated dermatoses, infections and tumours. Dermatopathological challenges stem mainly from the altered histopathological profile of established cutaneous entities compared with that in the HIV-unaffected population, the emergence of new diseases and the impact of therapeutic modalities on cutaneous lesions. This review focuses on some of these diagnostic dilemmas, with emphasis on the following challenges: (i) infective diagnostic pitfalls; (ii) itchy papular skin lesions; (iii) co-lesional comorbid diseases; (iv) drug-induced disease alterations; and (v) neoplastic and pseudoneoplastic proliferations. The drug-induced alterations include highly active antiretroviral therapy-associated disease modifications.

Histological variants of cutaneous Kaposi sarcoma

This review provides a comprehensive overview of the broad clinicopathologic spectrum of cutaneous Kaposi sarcoma (KS) lesions. Variants discussed include: usual KS lesions associated with disease progression (i.e. patch, plaque and nodular stage); morphologic subtypes alluded to in the older literature such as anaplastic and telangiectatic KS, as well as several lymphedematous variants; and numerous recently described variants including hyperkeratotic, keloidal, micronodular, pyogenic granuloma-like, ecchymotic, and intravascular KS. Involuting lesions as a result of treatment related regression are also presented.