A 34-year-old man came to the office due to white plaques on his buccal mucosa that he incidentally discovered while brushing his teeth. After appropriate workup, he was found to be HIV positive, with a CD4+ T lymphocyte count of 280/mm³. He was referred to an infectious diseases specialist for follow-up but was noncompliant with appointments. The patient returns 3 years later due to several months of pain and itching in the perirectal area. He also has intermittent rectal bleeding and often sees bright red blood on the tissue after wiping. The patient did not seek medical care because he thought he had hemorrhoids. On examination, a single, hard mass with superficial ulceration measuring approximately 2x2 cm is noted in the anal canal. No hemorrhoids are present. There is no palpable regional lymphadenopathy. Which of the following pathogens is most likely responsible for this patient's current anal pathology?

Question

Quizplus · Accepted Answer

This patient with HIV likely has anal squamous cell carcinoma given the duration of pain, itching, and rectal bleeding in addition to the visible ulcerative mass (anal cancers are ulcerative in >50% of cases). Anogenital squamous cell carcinomas and their precursors, squamous intraepithelial lesions, have been linked to human papillomavirus (HPV) infection. Intraepithelial neoplasias of the cervix, vulva, penis, and anus have a well-documented association with HPV types 16 and 18. A strong correlation between HPV and invasive carcinoma has been established for cervical cancer. Immunodeficiency states (eg, AIDS) increase host susceptibility to HPV infection and more severe infection. HIV-positive men who have sex with men are at increased risk of developing anal squamous cell carcinoma (anal intercourse is hypothesized to be related), and HIV-positive women are more prone to developing cervical squamous cell carcinoma. (Choice A) Adenoviruses can cause severe upper respiratory illnesses, pneumonia, and disseminated infection in immunosuppressed patients. (Choices B and E) HIV-positive patients often experience reactivation of latent Epstein-Barr virus (EBV) infection. EBV replication in such patients is associated with certain lymphomas and with oral hairy leukoplakia, which typically manifests as white plaques on the lateral tongue margins (this patient's white buccal plaques on initial diagnosis were more likely thrush due to Candida). (Choice C) Chlamydia trachomatis causes lymphogranuloma venereum (LGV), characterized by an ulcerative or vesicular lesion on the external genitalia followed by significant regional lymphadenopathy. Proctitis with tenesmus and bloody discharge can be seen with both LGV and anal carcinoma; however, LGV has a less indolent clinical course, and painful lymphadenopathy is a cardinal feature. (Choice D) HIV-positive patients with CD4+ cell counts <100/mm³ are at significantly increased risk of developing cytomegalovirus (CMV) infection, which most frequently causes retinitis in AIDS patients. CMV involvement of the gastrointestinal tract typically manifests as esophageal ulcers or colitis, not anal masses. (Choice F) Although AIDS increases the prevalence of herpes simplex virus type 2 (HSV-2) infection and the frequency of symptomatic genital herpes recurrences, HSV-2 is not typically associated with anogenital carcinoma. A large, hard mass is not characteristic of herpetic lesions (classically painful vesicles or ulcers). Educational objective: Human papillomavirus (HPV) types 16 and 18 are strongly associated with anal and cervical squamous cell carcinoma. HIV infection increases the prevalence of HPV infection and the risk of anal carcinoma; this risk is further augmented in men who have sex with men. __________ References: Risk of human papillomavirus-associated cancers among persons with AIDS. (http://www.ncbi.nlm.nih.gov/pubmed/19648510) Anal cancer: an overview. (http://www.ncbi.nlm.nih.gov/pubmed/17522240)

A 34-Year-Old Man Came to the Office Due to White