Reply to: A Rare Case of Vulvar Skin Metastasis of Rectal Cancer After Operation

The document is a response to comments on a previous manuscript about cutaneous scrotal metastasis. The authors discuss the rarity of metastasis of visceral malignancies to the scrotum and vulva, which are embryologically derived from the same origin. They note that vulvar metastases from visceral malignancies are rare but seem to have a higher incidence than scrotal metastases, accounting for 5-8% of all vulvar malignancies. A study from 2003 reported 66 women treated over 57 years who developed vulvar metastasis, with nearly half having a primary gynecologic tumor. In contrast, a review of cutaneous scrotal metastasis identified only 29 men with metastases to the scrotum, with the most common primary tumor sites being the prostate and gastrointestinal tract. The prognosis for patients who develop scrotal or vulvar metastases is poor, with median survival times of 7.5 months and 2 months respectively. The authors conclude that a new skin lesion on the scrotum or vulva in a patient with a history of visceral malignancy should prompt consideration of cutaneous metastasis.