A 79-year-old man with vulvar apocrine adenocarcinoma and right inguinal lymph node metastasis underwent wide excision and free skin graft reconstruction of the primary lesion and right inguinal lymphadenectomy. However, left inguinal lymph node metastasis was noted after 11 months, and left inguinal lymphadenectomy was performed. Twelve days postoperatively, the patient developed left inguinal lymphocele. The lymphocele was drained percutaneously and compressed, but lymph secretion persisted and lymphocele skin necrosis was observed. Therefore, debridement and vacuum-assisted closure (VAC) therapy were performed in cooperation with the department of plastic surgery. Subsequently, lymph secretion declined and eventually stopped. The lymphocele scar was reconstructed with a free skin graft, and after further observation for 8 months, right lymph node swelling was noted. Nevertheless, on the left inguinal site, neither lymphocele recurrence nor inguinal lymph node metastasis was observed. In conclusion, VAC therapy might be beneficial in the treatment of postoperative inguinal lymphocele after lymphadenectomy.