AssessmentsHuman herpesvirus 8 (Kaposi sarcoma)
USMLE® Step 1 style questions USMLE
A 46-year-old man comes to his primary care provider regarding mouth discomfort and bleeding for the past several weeks. He noticed bleeding after brushing his teeth. The patient's medical history is notable for HIV infection, and he says that he has been poorly compliant with his antiretroviral medication. Physical examination shows an intraoral dark-brown lesion with an overlying plaque which is easily scraped. Biopsy of the lesion shows significant lymphocyte infiltration and the presence of spindle cells. Which of the following is the most likely diagnosis?
Reproduced from from: Wikimedia Commons
Content Reviewers:Viviana Popa, MD
HHV-8 is one of the seven known oncoviruses, meaning viruses that cause cancer in people.
Human herpesvirus 8 is a large double stranded linear DNA virus surrounded by an icosahedral capsid, which is a spherical protein shell made up of 20 equilateral triangular faces.
The capsid is covered by a protein layer called the tegument, and finally enclosed in an envelope, which is a lipid membrane that contains viral glycoproteins and is acquired from the nuclear membrane of host cells.
HHV-8 is transmitted through sexual contact and once in the body it uses the viral glycoproteins on its envelope to enter a wide variety of cells such as B cells, endothelial cells, macrophages and epithelial cells.
Now, the virus life cycle has two phases - a latent phase and a lytic phase.
In the latent phase, the virus just hangs out in the cell without destroying it, and expresses the viral latency-associated nuclear antigen, or LANA-1.
So when LANA-1 inhibits p53, that prevents apoptosis and leads to uncontrolled cellular pro