Pediatric Surgery, Al Azher University, Cairo, Egypt
Raphe means the line of union of the two halves of various symmetrical body parts, and the term median raphe refers to the perineal raphe, which is also known as the median raphe of the perineum; and it is divided anatomically to: penile raphe, scrotal and perineal raphe. This line starts just anterior to the anus and extends through the scrotum, continuing on the ventral surface of the penis and prepuce; it is usually darker in colour than the surrounding skin, generally deep pink or brown.
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KeywordsAbsent median rapheProminent median rapheWide median rapheSplitted rapheBucket handle malformationMedian raphe cystBeaded median raphePearly penile papules
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Raphe means the line of union of the two halves of various symmetrical body parts, and the term median raphe refers to the perineal raphe, which is also known as the median raphe of the perineum; and it is divided anatomically to: penile raphe, scrotal and perineal raphe (Fig. 16.1). This line starts just anterior to the anus and extends through the scrotum, continuing on the ventral surface of the penis and prepuce; it is usually darker in colour than the surrounding skin, generally deep pink or brown (Fig. 16.2).
Anatomical segments of median raphe
Normal appearance of median raphe
Genital Median Raphe (GMR) is a result of a fetal developmental phenomenon whereby the scrotum (the developmental equivalent of the labia in females) and penis close toward the midline and fuse, to form this line which represents the superficial effects of the midline fusion of ectoderm along these areas, as development progresses, the ectodermal edges of the urethral groove begin to fuse to form the median raphe  (Fig. 16.3). This embryological line or ridge may be subjected to a various anomalies, which not well known by many practitioners, and can thus pass unnoticed, these anomalies will be highlighted with some details.
Urethral groove before fusion to form median raphe from the ectoderm
Genital raphe, Penile raphe, Genitoperineal raphe and Median raphe.
Median raphe anomalies are not so common and rarely taken into consideration; and curiously these conditions receive little attention even in genitourinary textbooks, and they are generally classified in literature into one of only two groups: cysts or ectodermal canals. These anomalies are formed from outgrowing endoderm and ectoderm after closure. In a survey of 2880 babies aged from 1 day to 7 weeks we detect an overall incidence of about 2 %, with a wide spectrum ranging from simple anomaly like prominent raphe to a raphe cyst .
16.2 Significance of GMR Anomalies
Pathology of the GMR anomalies may be simple, carries no direct impact on the child health and in many occasions needs no surgical intervention, but its significance mainly came from the serious associated anomalies, which are usually hidden and may be only disclosed after detection of GMR anomalies; as we will see in cases of intact prepuce megameatus for example. Recently with the advance in ultrasound techniques, median raphe could be visualised accurately antenatally as an indictor not only for sex determination, where the male fetus was recognised by the presence of the scrotal sac as a rounded echogenic structure separated by an echogenic median raphe , but also may give a hint about an associated anomalies; like hypospadias, and as we will see from the wide range of GMR anomalies, it may be used in the future for more detection and diagnosis of other congenital genitourinary anomalies antenatally.
Anomalies of median raphe classified to:
Absent median raphe
Prominent Median Raphe
Wide median Raphe
Splitted median Raphe
Hyperpigmented Median Raphe
Short Contracted Raphe
Deviation of Raphe
Bucket handle malformation
Median raphe cyst
Beaded median raphe
Pearly penile papules
16.2.1 Absent Median Raphe
Complete absence of penile raphe with flat redundant skin covering the penile shaft is a very rare anomaly which may be detected with different types of hypospadias (Fig. 16.4), and it is also reported as an associated anomaly with transverse testicular ectopia , usually perineal raphe is normal in such cases.
Absent penile raphe with coronal hypospadias in a circumcised child
16.2.2 Prominent Median Raphe
Normally GMR identified by its little prominence than the rest of the penile skin around it, but abnormal extensively prominent raphe looks like a ridge was detected in association with other anomalies like hypospadias, imperforate anus, and in rare cases of Townes–Brocks syndrome (an autosomal dominant disorder with multiple malformations and variable expression, major findings include external ear anomalies, hearing loss, preaxial polydactyly and triphalangeal thumbs, imperforate anus, and renal malformations) .. In many severe cases of hypospadias the GMR was a very prominent midline ridge extending from the the anal orifice to the hypospadiac urinary meatus (Fig. 16.5). Prominent GMR have to be differentiated from others anomalies like: wide, hyperpigmented and splitted types.
Prominent Raphe with an anterior penile hypospadias
16.2.3 Wide Median Raphe
Abnormal wideness of median raphe; either flat or prominent probably due to the defective fusion of the ectoderm, or failure of maturation of the midline mesodermal components, and it may be presented as a prominent widely separated median raphe which may be detected in cases of anorectal malformations (Fig. 16.6). This wideness may affect the whole penile, scrotal and perineal raphe, or may be partially affecting only the penile raphe, and such cases may hide a megameatus with an intact prepuce (Fig. 16.7) (This issue will be discussed with some details in Chap. 20). Wide GMR may be contracted with shortening of the scrotal raphe and results in disfigurement of scrotum (Fig. 16.8), such cases need excision of the abnormal raphe tissue with a meticulous closure of the midline with an absorbable fine suture to avoid a further scar contraction.