A 35-year-old woman presents with multiple ulcerative lesions on the labia; Tzanck preparation shows multinucleated giant cells. What is the most likely diagnosis?

• A. Varicella Zoster Virus
• B. Cytomegalovirus
• C. Herpes Simplex Virus
• D. Human Papillomavirus

Answer: (C)

Genital herpes caused by herpes simplex virus is the most likely diagnosis. Tzanck preparations that show multinucleated giant cells point to a herpesvirus infection; the virus drives fusion of infected epithelial cells, creating these giant cells. When lesions are located on the labia and present as multiple ulcers, herpes simplex virus infection—especially HSV-2—is the classic cause.

Understanding the context helps: HSV-2 commonly causes painful, recurrent genital ulcers that can start as vesicles that rupture into shallow ulcers. Multinucleated giant cells on a Tzanck smear support herpesvirus involvement, although they aren’t perfectly specific since varicella-zoster virus can produce the same cells. The other organisms don’t fit as well here: cytomegalovirus isn’t a typical cause of new genital ulcers in a healthy adult and doesn’t usually present with the distinctive Tzanck smear findings; human papillomavirus causes warty lesions rather than ulcerative ones with multinucleated giant cells; varicella-zoster virus tends to produce a different distribution of vesicles or dermatomal herpes zoster rather than isolated genital ulcers.

Management involves antiviral therapy such as acyclovir, valacyclovir, or famciclovir, with dosing depending on whether this is a primary or recurrent episode, along with supportive care and counseling on transmission and prevention.