Perineal raphe with special reference to its extension to the anus: a histological study using human fetuses

Microphallus early management in infancy saves adulthood sensual life: A ‎‎comprehensive review

Microphallus/Micropenis is a rare condition with significant physical and psychological implications for affected individuals. This article comprehensively reviews micropenis, its etiology, epidemiology, and various treatment options. We conducted a thorough literature review to collect relevant information on micropenis and microphallus, as well as related disorders. Our primary databases were PubMed, Medline, and Google Scholar. We searched for articles published in English between 2000 and 2023. Our analysis included 67 review articles, 56 research studies, 11 case reports, one guideline, and one editorial. Our search terms included "microphallus", "micropenis", "congenital hypogonadotropic hypogonadism", "androgen insensitivity syndrome", "pediatric management of micropenis", "testosterone therapy", and "psychosocial implications of micropenis". We focused on diagnosing micropenis and related conditions, including hormonal assessments, medical and surgical treatment options, psychosocial and psychological well-being, sexual development of adolescents, and sociocultural influences on men's perceptions of penile size. Additionally, we explored parenting and family dynamics in cases of micropenis and disorders of sex development, implications of hormonal treatment in neonates, and studies related to penile augmentation procedures and their effectiveness. The article highlights the importance of early diagnosis and intervention in addressing the physical and psychological well-being of individuals with micropenis. Surgical procedures, such as penile lengthening and girth enhancement, and non-surgical approaches like hormonal therapy are explored. The significance of psychological support, education, and lifestyle modifications is emphasized. Early management and comprehensive care are crucial for individuals with micropenis, from infancy to adolescence and beyond. A multidisciplinary approach involving urologists, endocrinologists, and mental health professionals is recommended. Regular assessment of treatment effectiveness and the need for updated guidelines are essential to provide the best possible care. Healthcare professionals should prioritize early diagnosis, and neonatologists should measure stretched penile length in neonates. A collaborative effort is needed among professionals, parents, and affected individuals to create a supportive environment that recognizes worth beyond physical differences. Continuous research and evidence-based updates are crucial for improving care standards.

Development and growth of median structures in the human tongue: A histological study using human fetuses and adult cadavers

Glossectomy is a surgical procedure performed to remove all or part of the tongue in patients with cancer. The removal of a significant part of the tongue has a marked effect on speech and swallowing function, as patients may lose not only the tongue muscles but also the median lingual septum (MLS). Therefore, to achieve successful tongue regeneration, it is necessary to investigate the developmental processes of not only the tongue muscles but also the MLS. This study was conducted to clarify the mutual development of the tongue muscles and the MLS in human fetuses. Serial or semi-serial histological sections from 37 embryos and fetuses (aged 5-39 weeks) as well as nine adults were analyzed. The MLS appeared at Carnegie stage 15 (CS15), and until 12 weeks of gestation, abundant fibers of the intrinsic transverse muscle crossed the septum in the entire tongue. However, in near-term fetuses and adults, the contralaterally extending muscles were restricted to the deepest layer just above the genioglossus muscle. This finding indicates that the crossing transverse muscle showed the highest density at mid-term. A thorough understanding of both the MLS and the tongue muscles is necessary for successful tongue regeneration.

Distal vaginal atresia: a report of a rare type found a late-term fetus and its histological comparison with the normal pelvis

Solitary distal vaginal atresia is generally caused by a transverse septum or an imperforate hymen. We found a novel type of distal vaginal atresia in a late-term fetus (gestational age approximately 28 weeks) in our histology collection. This fetus had a vaginal vestibule that was closed and covered by a thick subcutaneous tissue beneath the perineal skin in the immediately inferior or superficial side of the imperforate hymen. The uterus, uterine tube, anus, and anal canal had normal development. The urethral rhabdosphincters were well-developed and had a normal topographical relationship with the vagina, but the urethrovaginal sphincter was absent. Thus, vaginal descent seemed to occur normally and form the vestibule. However, the external orifice of the urethra consisted of a highly folded duct with hypertrophied squamous epithelium. Notably, the corpus cavernosum and crus of the clitoris had poor development and were embedded in the subcutaneous tissue, distant from the vestibule. Normally, the cloacal membrane shifts from the bottom of the urogenital sinus to the inferior aspect of the thick and elongated genital tubercle after establishment of the urorectal septum. Therefore, we speculate there was a failure in the transposition of the cloacal membrane caused by decreased elongation of the genital tubercle. The histology of this anomaly strongly suggested that the hymen does not represent a part of the cloacal membrane, but is instead a product that appears during the late recanalization of the distal vagina after vaginal descent. The transverse septum was also likely to form during this recanalization.

Congenital Perineal Groove Defect in Monozygotic Twin Infants: A Literature Review

Perineal groove is a rare benign congenital anomaly with lesion that resembles perforation of mid-perineum or perineal raphe area. Most reported cases of congenital perineal groove presented as an isolated defect in term or early-term singleton female infants. Thus far, there is no reported case of this anomaly in monozygotic twins. Embryo pathogenesis of this female predominance congenital defect remains controversial. Many clinicians are unfamiliar with this congenital anomaly. This congenital defect tends to get self-resolved at around 2 year of age. Nevertheless, the exposed nonepithelized mucous membrane can carry risk of local infection or irritation with the possibility of requiring early surgical correction. The defect can be infrequently associated with other ano-urogenital malformations that required immediate surgical intervention. Most isolated cases tend to be asymptomatic and self-healed with expectant management. Surgical correction may be considered if not healed after 2 years of age. Early diagnosis at birth is important to avoid misdiagnoses at later age for trauma, dermatitis, sexual abuse, and risk of unnecessary aggressive intervention. Early parental counseling for providing good hygiene and close follow-up is important to prevent infection or inflammation. Presentation of this anomaly in both monozygotic twins may support the hypothesis of potential disruption during embryo morphogenesis stages.

A missing distal complex of the external and internal anal sphincters: a macroscopic and histologic study using Japanese and German elderly cadavers

The lower margin of the internal anal sphincter (IAS) is considered to lie on a J-shaped, subcutaneous part (SCP) of the external anal sphincter (EAS). The lower IAS is united with the J-shaped SCP to form a smooth-striated muscle complex. In the first part of this study, we ensured the presence of the J-shaped EAS in the lateral wall of the anal canal from 12 near-term fetuses. Second, in the lateral anal wall, the examination of the longitudinal section from 20 male and 24 female Japanese cadavers (72-95 years-old) demonstrated that the J-shaped EAS was lost in 15 (34%) due to the very small SCP. Third, we demonstrated that the J-shaped EAS was restricted in the latera anal wall using longitudinal histological sections of the anal canal from 11 male Japanese cadavers (75-89 years-old). Therefore, a site-dependent difference in the IAS-EAS configuration was evident. Finally, we compared a frequency of the lost J-shape between human populations using 10 mm-thick frontal slices from 36 Japanese and 28 German cadavers. The two groups of cadavers were compatible in age (a 0.2-years' difference in males). The macroscopic observations revealed that the J-shaped EAS was absent from 13 (36%) Japanese and six (20%) German specimens, suggesting that the SCP degeneration occurred more frequent in elderly Japanese than elderly German individuals (p < 0.05). The distal IAS-EAS complex seemed to push residual feces out of the anal canal at a transient phase from evacuation to closure. The absence might be the first sigh of anal dysfunction.

Perineal Groove: An Anorectal Malformation Network, Consortium Study

OBJECTIVE

To review the Anorectal Malformation Network experience with perineal groove (PG) focusing on its clinical characteristics and management.

STUDY DESIGN

Data on patients with PG managed at 10 participating Anorectal Malformation Network centers in 1999-2019 were collected retrospectively by questionnaire.

RESULTS

The cohort included 66 patients (65 females) of median age 1.4 months at diagnosis. The leading referral diagnosis was anal fissure (n = 20 [30.3%]): 23 patients (34.8%) had anorectal malformations. Expectant management was practiced in 47 patients (71.2%). Eight (17%) were eventually operated for local complications. The median time to surgery was 14 months (range, 3.0-48.6 months), and the median age at surgery was 18.3 months (range, 4.8-58.0 months). In the 35 patients available for follow-up of the remaining 39 managed expectantly, 23 (65.7%) showed complete or near-complete self-epithelization by a mean age 15.3 months (range, 1-72 months) and 4 (11.4%) showed partial self-epithelization by a mean age 21 months (range, 3-48 months). Eight patients showed no resolution (5 were followed for ≤3 months). Nineteen patients (28.7%) were primarily treated with surgery. In total, 27 patients were operated. Dehiscence occurred in 3 of 27 operated patients (11.1%).

CONCLUSIONS

PG seems to be an underestimated anomaly, frequently associated with anorectal malformations. Most cases heal spontaneously; therefore, expectant management is recommended. When associated with anorectal malformations requiring reconstruction, PG should be excised in conjunction with the anorectoplasty.

Reorganization of mammalian body wall patterning with cloacal septation

Septation of the cloaca is a unique mammalian adaptation that required a novel reorganization of the perineum–the caudal portion of the trunk body wall not associated with the hindlimb. Fish, the basal vertebrates, separate ventrolateral body wall musculature of the trunk into two discrete layers, while most tetrapods expand this pattern in the thorax and abdomen into four. Mammals, the only vertebrate group to divide the cloaca into urogenital and anorectal portions, exhibit complex muscle morphology in the perineum. Here we describe how perineal morphology in a broad sample of mammals fits into patterning of trunk musculature as an extension of the four-layer ventrolateral muscular patterning of the thorax and abdomen. We show that each perineal muscle layer has a specific function related to structures formed by cloacal septation. From superficial to deep, there is the subcutaneous layer, which regulates orifice closure, the external layer, which supplements both erectile and micturition function, the internal layer, which provides primary micturition and defecation regulation, and the transversus layer, which provides structural support for pelvic organs. We elucidate how the four-layer body wall pattern, restricted to the non-mammal tetrapod thorax and abdomen, is observed in the mammalian perineum to regulate function of unique perineal structures derived from cloacal septation.

Midline sensory nerve supply to the anoscrotal junction: a study using human male fetuses

The origin of the posterior scrotal nerve is considered to be the bilateral pudendal nerves but the course to the midline is still obscure. Using 5 late-stage human male fetuses, we identified the single nerve through the intramuscular midline septum of the bulbospongiosus and the bilateral nerves along the left and right sides of the septum. Thus, the posterior scrotal nerve showed a variation: a single midline trunk or bilateral nerves. Branches of the bilateral pudendal nerves ran medially between the muscle and Cowper's gland and, at the midline area, they joined or associated closely. During the proximal course, much or less, the nerve penetrated the superior part of the muscle. The nerve entered the subcutaneous tissue at and near the perineal raphe. The communication with intrapelvic autonomic nerves were suggested behind Cowper's gland. Notably, the midline skin immediately anterior to the anus carried a considerable dense supply of thin sensory nerves. However, these nerves seemed to come from a space between the rectal smooth muscle and the external anal sphincter, not from the posterior scrotal nerve. Therefore, surgical treatment of the intersphincteric layer was likely to injure the original sensory nerve supply to the anterior anal skin.