Keywords
congenital anomaly - perineal groove - perineal defect - newborn
Congenital perineal groove is characterized by an exposed erythematous nonepithelized
mucous membranes that resembles exposed wet erythematous sulcus, inflammation, or
rupture of the midperineum area. This lesion extends vertically downward from the
posterior portion of the vaginal fourchette to the anterior rim of the anus.[1]
[2]
[3] This lesion resembles failure of mid-perineum fusion or failure of midperineum skin
epithelialization.[3]
Case Presentation and Management
Case 1
At 37 weeks gestational age (GA) a white female with birthweight (BW) of 3,450 g was
delivered by cesarean section (CS) due to recurrent CS and placenta previa. Apgar
scores were 8 and 9 at 1 and 5 minutes, respectively. Infant was admitted to the neonatal
intensive care unit (NICU) for suspected imperforated anus. Infant's mother was a
25-year-old gravida 3 and para 3 (G3P3) with good prenatal care. All prenatal tests
were negative and there was no history of smoking, drinking alcohol, or abusing substances.
Placental histopathology showed mild placentomegaly, acute chorioamnionitis without
funisitis, and placenta previa. There was no family history of congenital anomalies.
Physical examination of the infant was normal except for the perineal area that showed
a lesion, which was suspicious for congenital or iatrogenic perineal rupture or imperforated
anus. The perineal defect was noted stretching vertically upward from 12 o'clock position
of the anal rim toward the posterior vaginal fourchette, with a wet groove-like unkeratinized
erythematous mucosal lesion ([Fig. 1]). Urethra and vaginal orifices were intact and within appropriate position. Infant
did not show any signs of urination problem. The diagnosis of imperforated anus was
ruled-out with normal anorectal examination and infant was stooling from the well-positioned
anal opening located posterior to the lesion. The ultrasounds of the head, pelvic,
renal, and spine were normal. The skeletal survey was also normal, and an echocardiogram
showed a small secundum atrial septal defect with a tiny patent ductus arteriosus.
The hospital course was uneventful except for transient hypoglycemia and received
empiric antibiotics for suspected infection with negative blood culture. She was discharged
home at 5 days of life. Follow-up at 4 months of age revealed no complications.
Fig. 1 (Case 1) Wet groove between the vulva and anus.
Case 2
At 37 weeks GA an African American female with BW of 3,510 g was delivered by CS due
to recurrent CS and preeclampsia. Apgar scores were 7 and 8 at 1 and 5 minutes, respectively.
Pregnancy was complicated by insulin-controlled gestational diabetes, chronic hypertension,
and preeclampsia. Infant was admitted to the NICU for transient hypoglycemia and suspected
perforated perineum with a four-vessel umbilical cord (two veins and two arteries).
Mother was a 41-year-old G5P5 with good prenatal care. All prenatal tests were negative
and there was no history of drinking alcohol, smoking, or abusing substances. Placental
histopathology was normal except for increased fetal nucleated red blood cells consistent
with fetal hypoxia. There was no family history of congenital malformations.
Infant's physical examination was normal for all organ systems except for four-vessel
umbilical cord and perineal defect. The perineal defect was a wet groove-like erythematous
nonepithelized mucous membrane that extended vertically downward from 6 o'clock position
of the posterior vaginal fourchette to the anterior rim of the anal orifice and resembled
ruptured perineal area ([Fig. 2]). Urethra, vaginal, and anal orifices were intact and well-positioned. Stooling
originated from an intact anal opening, and no fecal or urinary incontinence was noted.
Head, renal, pelvic, and spine ultrasounds were all unremarkable. Echocardiogram to
rule out any congenital cardiac anomaly that could be associated with four-vessel
cord was reported as normal. Skeletal survey was normal. Hospital course was unremarkable
and she was discharged home with her parents at 3 days of life. At 1-year follow-up,
it showed healing of the perineal groove lesion.
Fig. 2 (Case 2) Wet groove between the vulva and anus.
Discussion
Congenital perineal groove is a rare and benign malformation. It is mostly presented
in female infants as an isolated anomaly. So far only 23 cases have been reported
in medical literatures.[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11] In rare cases, it may be associated with other regional anomalies of anogenital
and/or urogenital system such as anteriorly placed anus, ectopic anus, prolapsed anus,
or urinary tract malformation.[3]
[6]
[12] Both of our patients were delivered within 12-month period and were diagnosed at
birth. It is likely that the incidence of this congenital anomaly is underestimated
as it may be unrecognized earlier at birth, and/or later misdiagnosed as a diaper
rash, contact dermatitis, or trauma.[5]
[6]
In 1968, Stephens[3] described perineal groove as a congenital malformation that consists of three features:
(1) a wet groove in midperineum between the fourchette and the anus; (2) normal formation
of the vestibule including the urethra and vagina; and (3) hypertrophy of the minoral
tails that skirt the perineum and course posteriorly to join at the anus or to surround
it.
Pathogenesis of perineal groove remains unclear. However, embryological mechanisms
have been proposed as follows: (1) a relic of the open cloacal duct,[13] (2) midline fusion failure of medial genital folds between the perineal raphe and
the vestibule,[3]
[4] and (3) urorectal septum developmental defect during cloacal embryological stages
at 5th to 8th week of GA.[6]
[7]
[14] Given that the perineal groove anomaly was also reported in one male infant,[12] this congenital anomaly can be derived during the embryological development stage
of external genitalia. External genitalia of both sexes are developed from the genital
tubercle, genital folds, and labioscrotal folds. Therefore, failure of labioscrotal
folds fusion to form perineal raphe will cause perineal groove to occur.[2]
Histological reviews of the resected area varied from a nonkeratinized stratified
squamous epithelium without sebaceous glands or sweat glands or hair follicles,[3]
[4]
[15] to a simple columnar or stratified columnar or cuboidal epithelium of a rectal type
mucosa with intervening area of a nonkeratinized stratified squamous epithelium.[7]
[15] These findings resembled anorectal transitional zone epithelium, which implied that
this malformation probably associated with embryology defect during urorectal septum
development.[2]
[6]
[7]
Patients with this congenital malformation are at an increased risk of urinary tract
infection, inflammation, or infection of the nonepithelized mucosa, fecal continence,
or incontinence and other associated regional anomaly.[5]
[6] This lesion may be self-resolved and completely epithelized by the age of 1 to 2
years.[1]
[2]
[5]
[6] Surgical correction can be done mainly for cosmetic reason, if the lesion is not
epithelialized by the age of 2 years. However, there are also some reports that the
lesion may need surgical correction earlier than the age of 2 years for clinical reasons
such as repeated inflammation or infection of the nonepithelized area from exposure
to mucous drainage, wet secretion from the urethra, vagina, or anal sites.[5]
[6] Because this lesion resembles rupture or inflammation of perineum region, failure
to recognize this lesion at birth will lead to misdiagnosis such as infection, irritant
dermatitis, ulcerated hemangioma, lichen sclerosis, trauma, or even sexual abuse.[5]
Conclusion
This uncommon benign congenital malformation tends to be self-epithelialized. However,
surgical referral is warranted if it involves other regional anomalies, recurrent
infection, or ulceration of the perineal groove, failure of epithelialization after
the age of 2 years or for a cosmetic reason. Early recognition of congenital perineal
groove at birth is important for health care providers to deliver an informed parental
counseling, appropriate follow-up, and to prevent an unnecessary surgical or medical
intervention.
