Malignancy Masquerade: Inclusion-Negative Herpes Simplex Virus Rectal Pseudotumor in a Patient With HIV

Area of Science:

• Infectious Diseases
• Gastroenterology
• Oncology

Background:

• Herpes simplex virus (HSV) is a common sexually transmitted infection.
• Immunocompromised patients may present with atypical HSV manifestations, including masses.
• HSV pseudotumors, particularly in the rectum, are rare and underreported.

Observation:

• A 51-year-old male with well-controlled HIV-1 presented with a rectal mass.
• The mass raised initial concerns for bacterial infection or malignancy.
• Histologic examination and HSV immunohistochemical staining on biopsy were negative.

Findings:

• The rectal mass significantly improved with empiric intravenous acyclovir treatment.
• This clinical response strongly suggests a diagnosis of a rectal HSV pseudotumor.
• The case underscores the diagnostic challenge of HSV pseudotumors, especially with negative staining.

Implications:

• Clinicians should consider atypical HSV infections in the differential diagnosis of rectal masses in immunocompromised patients.
• Empiric antiviral therapy can be diagnostic and therapeutic for suspected HSV pseudotumors.
• Further research is needed to understand the pathogenesis and diagnostic criteria for HSV pseudotumors.