HIV-Associated Malignancies & Prophylaxis
- Crack Medicine
- 3 hours ago
- 4 min read
TL;DR
HIV-Associated Malignancies & Prophylaxis are commonly tested concepts in MRCP Part 1, combining infectious disease, oncology, and immunology. Candidates must recognise the classic AIDS-defining cancers—Kaposi sarcoma, non-Hodgkin lymphoma, and cervical cancer—and understand how CD4 thresholds guide opportunistic infection prophylaxis. Exam questions frequently focus on viral associations (HHV-8, EBV, HPV), recognition of malignancy patterns, and the correct prophylactic drugs. Mastering these high-yield links improves both exam performance and clinical reasoning.
Why this matters
In the MRCP Part 1 examination, HIV medicine is often tested through integrated clinical questions that combine immunology, infectious disease, and oncology. Among these topics, HIV-Associated Malignancies & Prophylaxis are particularly high-yield because they require candidates to connect CD4 count thresholds, viral oncogenesis, and opportunistic infection prevention.
Before the widespread use of combination antiretroviral therapy (ART), malignancies such as Kaposi sarcoma and aggressive lymphomas were common complications of HIV infection. Modern ART has dramatically reduced their incidence, but they remain clinically important and frequently appear in examination scenarios.
Candidates preparing for the exam should review these concepts alongside the broader MRCP Part 1 overview and practise application through question banks such as the Free MRCP MCQs.
Core sections
1. AIDS-Defining Malignancies
The classic AIDS-defining malignancies are a core exam topic.
Malignancy | Viral Association | Key Clinical Features |
Kaposi Sarcoma | Human herpesvirus-8 (HHV-8) | Violaceous skin lesions, oral mucosal involvement |
Non-Hodgkin Lymphoma | Epstein–Barr virus (EBV) | Aggressive B-cell lymphoma, extranodal disease |
Cervical Cancer | Human papillomavirus (HPV) | Persistent HPV infection → dysplasia → carcinoma |
These cancers signify advanced immune suppression and are central to exam questions testing the relationship between viral oncogenesis and HIV-related immunodeficiency.
2. Kaposi Sarcoma
Kaposi sarcoma is the most recognisable HIV-associated malignancy.
Clinical presentation
Purple or violaceous plaques and nodules
Frequently affects the skin of the legs, face, and trunk
Oral lesions commonly appear on the palate
Gastrointestinal and pulmonary involvement may occur
Pathogenesis
Kaposi sarcoma is caused by human herpesvirus-8 (HHV-8), which drives vascular tumour formation in the context of immune suppression.
Management principles
Initiation or optimisation of antiretroviral therapy
Local therapy for limited disease
Systemic chemotherapy for advanced disease
Exam insight
In MRCP questions, the description of purple vascular lesions in an HIV patient strongly suggests Kaposi sarcoma.
3. HIV-Associated Non-Hodgkin Lymphoma
HIV infection significantly increases the risk of aggressive lymphomas.
Common subtypes include:
Diffuse large B-cell lymphoma
Burkitt lymphoma
Primary central nervous system lymphoma
Key clinical clues
Rapidly enlarging lymph nodes
Constitutional “B symptoms” (fever, night sweats, weight loss)
Neurological deficits if CNS involvement occurs
These lymphomas are often associated with Epstein–Barr virus (EBV) infection and are characterised by rapid progression.
4. Cervical Cancer in HIV
Persistent infection with oncogenic human papillomavirus (HPV) significantly increases the risk of cervical cancer in women living with HIV.
Key points for MRCP revision:
HPV types 16 and 18 are most strongly associated with malignancy
Cervical cancer is an AIDS-defining condition
Screening intervals are typically more frequent in HIV-positive patients
Exam trap: Anal cancer is associated with HPV and HIV but is not AIDS-defining, unlike cervical cancer.
5. Non-AIDS-Defining Malignancies
With improved survival due to ART, the spectrum of malignancy in HIV has expanded.
Important examples include:
Anal carcinoma (HPV-related)
Hodgkin lymphoma
Lung cancer
Hepatocellular carcinoma (particularly with HBV or HCV coinfection)
These malignancies reflect chronic immune dysregulation and viral coinfection, and they occasionally appear in exam questions focusing on long-term HIV complications.
6. Opportunistic Infection Prophylaxis
Understanding CD4 thresholds for prophylaxis is a critical MRCP topic.
CD4 Count | Infection Prevented | Recommended Prophylaxis |
<200 cells/mm³ | Pneumocystis jirovecii pneumonia (PJP) | Co-trimoxazole |
<100 cells/mm³ | Toxoplasma gondii | Co-trimoxazole |
<50 cells/mm³ | Mycobacterium avium complex (MAC) | Azithromycin |
Important principle
Prophylaxis decisions are primarily CD4-driven rather than symptom-driven.
7. Role of Antiretroviral Therapy
Combination antiretroviral therapy (ART) has transformed the prognosis of HIV infection.
Benefits include:
Immune reconstitution
Reduced opportunistic infections
Lower incidence of Kaposi sarcoma and lymphoma
Improved survival
However, malignancy risk does not disappear entirely because chronic inflammation and viral coinfections persist.
8. High-Yield Revision Points for MRCP Part 1
Kaposi sarcoma is caused by HHV-8 infection.
Non-Hodgkin lymphoma in HIV is frequently linked to EBV.
Cervical cancer is an AIDS-defining malignancy.
Kaposi sarcoma lesions are typically violaceous vascular nodules.
PJP prophylaxis begins when CD4 <200 cells/mm³.
Co-trimoxazole protects against both PJP and toxoplasmosis.
EBV is strongly associated with primary CNS lymphoma in HIV.
ART significantly reduces opportunistic infection risk.
Anal cancer is HIV-associated but not AIDS-defining.
CD4 thresholds guide prophylaxis decisions in HIV care.
Practical examples / mini-cases
Clinical Scenario
A 41-year-old man with untreated HIV presents with multiple purple plaques on his lower limbs and palate. His CD4 count is 110 cells/mm³.
Which diagnosis is most likely?
A. Bacillary angiomatosisB. Kaposi sarcomaC. AngiosarcomaD. Pyogenic granuloma
Correct answer: B. Kaposi sarcoma
Explanation
Kaposi sarcoma is an AIDS-defining malignancy caused by HHV-8. The characteristic violaceous skin lesions in an immunocompromised patient with low CD4 count strongly support the diagnosis.
Common pitfalls (5 bullets)
Confusing Kaposi sarcoma with bacillary angiomatosis (caused by Bartonella species).
Forgetting that cervical cancer is AIDS-defining.
Misremembering the CD4 threshold for PJP prophylaxis (<200 cells/mm³).
Assuming all HIV-related cancers are AIDS-defining.
Missing the EBV association with HIV-related lymphoma.
FAQs
Which cancers are AIDS-defining in HIV?
The three classical AIDS-defining malignancies are Kaposi sarcoma, non-Hodgkin lymphoma, and invasive cervical cancer. Their presence indicates severe immunosuppression.
When should Pneumocystis prophylaxis start?
Prophylaxis with co-trimoxazole is recommended when the CD4 count falls below 200 cells/mm³, or if there is a history of oropharyngeal candidiasis.
What virus causes Kaposi sarcoma?
Kaposi sarcoma is caused by human herpesvirus-8 (HHV-8). Immunosuppression allows the virus to drive angioproliferative tumour growth.
Why is lymphoma common in HIV?
HIV causes chronic immune activation and impaired immune surveillance. This allows EBV-infected B cells to proliferate, increasing lymphoma risk.
Does antiretroviral therapy reduce cancer risk?
Yes. Effective antiretroviral therapy restores immune function, reducing both opportunistic infections and several HIV-associated malignancies.
Ready to start?
Success in MRCP Part 1 requires consistent exposure to exam-style clinical scenarios. Reinforce these high-yield HIV concepts by:
Reviewing the MRCP Part 1 overview
Practising exam questions through the Free MRCP MCQs
Testing your readiness with a Start a mock test
Structured practice helps convert theoretical knowledge into exam performance.
Sources
MRCP(UK) Examination Blueprint – https://www.mrcpuk.org
British HIV Association Guidelines – https://www.bhiva.org
World Health Organization HIV Guidelines – https://www.who.int/health-topics/hiv
Kumar & Clark’s Clinical Medicine
Oxford Handbook of Infectious Diseases and Microbiology
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