Perineal carcinoma of unknown origin is a rare and aggressive disease, so an early diagnosis and adequate treatment are essential to prevent its progression. We report the first series of cases of perineal carcinoma of unknown origin: (I) a 62-year-old male patient being followed up for a urethral stricture treated with periodic dilations with subsequent development of perineal abscesses and perineal carcinoma; (II) a 67-year-old male patient who consults for urinary discomfort associated with a perineal abscess. Recurrence of the abscess in the first month revealed the presence of an underlying perineal carcinoma; (III) a 78-year-old male patient that underwent urethroplasty with graft with subsequent regimen of periodical dilations. Recurrent formation of perianal abscesses revealed the presence of an underlying perineal carcinoma; and (IV) a 78-year-old male patient with history of in situ penile carcinoma treated by glans resurfacing. He consulted for penile pain, and imaging tests revealed a perineal abscess adjacent to the left corpus cavernosum. The core needle biopsy revealed a squamous cell carcinoma. Penile exploration and negative glans biopsy ruled out possible recurrence of penile carcinoma. The form of presentation of the disease has been very similar in all patients, demonstrating the presence of perineal abscess in all cases. Two patients had inguinal lymph node disease at diagnosis. All patients were treated by surgery, and three of them required adjuvant systemic treatment. Surgery combined with systemic treatment is probably the best option if the patient's conditions allow it.