Primary perineal hernias are rare and can be a diagnostic challenge. We report the case of a 45-year-old female patient who presented with painless perineal swelling suggestive of perineal hernia. Computed tomography (CT) scanning revealed a pelvic mass herniating through the pelvic floor into the perineum. The lesion was completely excised by an abdominoperineal approach. Histopathological examination of the lesion revealed a leiomyoma. This case report suggests that the possibility of perineal herniation of a pelvic leiomyoma should be considered in a female patient with suspected primary perineal hernia. We recommend an abdominoperineal approach for the surgical management of such a lesion.