Penile Agenesis

(1)

Pediatric Surgery, Al Azher University, Cairo, Egypt

Abstract

Congenital absence of the penis, is a rare anomaly caused by developmental failure of the genital tubercle, the first published case dates to 1701, Aphallia could be associated with urethral atresia and absent urinary meatus, but few cases may have a normal urethra and meatus. some cases reported with other syndromes, like caudal regression syndrome. In the past all such cases are reassigned as a female with orchidectomy and vaginoplasty, but recently the trend of penile reconstruction either by grafting, tissue engineering or even penile transplant became applicable and acceptable by the families.

Keywords

AphalliaApeniaPenile agenesisAblatio penisPopliteal pterygium syndromePenile transplant

Nomenclature

Aphallia (this term is also applicable for female without clitoris), Apenia, Penile Agenesis, Ablatio Penis, but the last term usually used for acquired or posttrumatic vanished penis.

Definition

Congenital absence of the penis, is a rare anomaly caused by developmental failure of the genital tubercle. Penile agenesis occurs often as a consequence of testicular agenesis, but the reverse is never the case. Most patients have no known family history and usually have an otherwise normal male anatomy and usually, the scrotum is normal but testes are undescended, there are many cases reported where the both testicles are normally descended with normal development. The urethra opens at any point of the perineal midline from over the pubis to, most frequently, the anus or anterior wall of the rectum (Fig. 8.1).

Fig. 8.1

Neonate with aphallia but a normal scrotum and testicles

8.1 Historical Background

The first published case dates to 1701 and was recorded by the French surgeon Saviard (1656–1702), under the heading of a “child who had no rod”, but the first full description of this anomaly was by Imminger in 1853, since then more than 100 cases have been reported in the literature, but very recently there are many cases in the process of reporting [1].

8.2 Approximate Incidence

One in 10 to 30 million population, but a higher incidence detected in institutes doing autopasy for stillbirth and cases neonatal death, and that is explain many cases escape record.

8.3 Aetiology

Penile agenesis results from failure of development of genital tubercles. The definitive urogenital sinus in such cases ends in the perineum without the normal proliferation, hence, it does not move anteriorly and cephalic to the ventral border of penis, the urethra therefore opens in the perineum, at or near the anal border.

Agenesis of the penis may occurs as a consequence of single gene disorders, teratogenic effects, or malformation sequences and associations of unrecognized patterns of anomalies, it thus should be considered as a developmental field defect. Its concurrence with scrotal hypoplasia, absent raphe, and anal anomalies implies a major disturbance of the caudal mesoderm, in such cases severe renal defects are usually seen, and the prognosis is poor. When the patient has a patent urethra and normal scrotum, raphe, and testes the baby may survive with such anomaly, however penile agenesis may be a localized malformation of the genital tubercle and potentially related to penoscrotal transposition. Reports indicate that aphallia may be associated with pregnancy complicated by poorly controlled maternal diabetes [2].

8.4 Associated Anomalies

More than 50 % of patients with penile agenesis have associated genitourinary anomalies, the most common of which is cryptorchidism; renal agenesis and dysplasia. Cardiovascular gastrointestinal defects, such as caudal axis anomalies, also have been described. Skoog and Belman (1989) [3] reviewed 60 reports of aphallia and found that the more proximal the urethral meatus, the greater the likelihood of neonatal death and the higher the incidence of other anomalies. Sixty percent of patients had a postsphincteric meatus located on a peculiar appendage at the anal verge, this group of patients had the highest survival rate (87 %) and the lowest incidence of other anomalies (1.2 per patient). Twenty-eight percent of patients had presphincteric urethral communications (prostatorectal fistula), and there was a 36 % neonatal mortality rate. Twelve percent had urethral atresia and a vesicorectal fistula for drainage. This group had the highest incidence of other anomalies and a 100 % mortality rate.

8.5 Classifications

Skoog and Belman [3] suggested three variants, based on urethral position in relationship to the anal sphincter, as: Postsphincteric; Presphincteric (Prostatorectal fistula) and Urethral atresia. More proximal the bladder outlet, greater is the likelihood of other anomalies and death.

We adopted herein a simple classification after reviewing many cases and literature concerning with this anomaly according to presence or absence of external urinary meatus, and if this anomaly associated or not with another syndromes:

Aphallia with urethral atresia and absent urinary meatus (Fig. 8.2).

Fig. 8.2

Aphallia without any urethral opening, testicles, scrotum, or raphe, there is also an imperforate anus, he had only a skin appendage at the pubic region
Aphallia with normal urethra and meatus.
Aphallia with other syndromes (Figs. 8.3 and 8.4).

Fig. 8.3

Aphallia with Exomphalos

Fig. 8.4

Aphallia with Popliteal Pterygium syndrome
Aphallia with caudal regression syndrome.

This classification correlated with Evans et al. who suggest that most cases can be classified into either a severe form (16 %) with renal aplasia or dysplasia and other caudal anomalies or a second group (72 %) with low mortality and fewer additional malformations [4].

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