A 28-year-old woman presents to her family physician complaining that she has a "growth" in her genital area. She states that she first noticed it 3 weeks ago and it seems to have grown somewhat since that time. She has hypothyroidism, for which she takes thyroid hormone replacement. She has no other medical problems and has never had surgery. She has had 3 sexual paners over her lifetime and is currently involved in a monogamous relationship. She has never had a sexually transmitted disease in the past. Examination demonstrates two nontender 6 mm well-circumscribed, flesh-colored, papillated, oval lesions on the labia majora. There is no ulceration, erythema, purulence, or inguinal lymphadenopathy. Which of the following is the most likely diagnosis?