Congenital dermal sinus is an uncommon form of cranial or

spinal dysraphism Neural tube defects (NTDs) are a group of birth defects in which an opening in the Vertebral column, spine or cranium remains from early in human development. In the third week of pregnancy called gastrulation, specialized cells on the dorsal si ...

. It occurs in 1 in 2500 live births. It occurs as a dermal indentation, found along the midline of the

neuraxis The neuraxis, also known as the neuroaxis is the axis of the central nervous system. It extends from the brain to the spinal cord and denotes the direction in which the central nervous system lies in both development and in mature organisms. Ear ...

and often presents alongside infection and neurological deficit. Congenital dermal sinus form due to a focal failure of dysjunction between the cutaneous

ectoderm The ectoderm is one of the three primary germ layers formed in early embryonic development. It is the outermost layer, and is superficial to the mesoderm (the middle layer) and endoderm (the innermost layer). It emerges and originates from the o ...

and

neuroectoderm Neuroectoderm (or neural ectoderm or neural tube epithelium) consists of cells derived from the ectoderm. Formation of the neuroectoderm is the first step in the development of the nervous system. The neuroectoderm receives bone morphogenetic pro ...

during the third to eight week of

gestation Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregn ...

. Typically observed in the

lumbar In tetrapod anatomy, lumbar is an adjective that means of or pertaining to the abdominal segment of the torso, between the diaphragm (anatomy), diaphragm and the sacrum. Naming and location The lumbar region is sometimes referred to as the lowe ...

and

lumbosacral Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

region, congenital dermal sinus can occur from the

nasion The nasion () is the most anterior point of the frontonasal suture that joins the nasal part of the frontal bone and the nasal bones. It marks the midpoint at the intersection of the frontonasal suture with the internasal suture joining the na ...

and

occiput The occipital bone () is a cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone lies over the occipital lobes of the ...

region down. Early diagnosis and treatment is crucial for cases of congenital dermal sinus. It ensures that neurological condition does not degrade and prevents infection. Diagnosis can be confirmed through the use of advanced

neuroimaging Neuroimaging is the use of quantitative (computational) techniques to study the neuroanatomy, structure and function of the central nervous system, developed as an objective way of scientifically studying the healthy human brain in a non-invasive ...

to observe the tract and associated

lesions A lesion is any damage or abnormal change in the tissue of an organism, usually caused by injury or diseases. The term ''Lesion'' is derived from the Latin meaning "injury". Lesions may occur in both plants and animals. Types There is no de ...

Embryogenesis

During normal development, cutaneous

separates from

to allow for the insertion of

mesoderm The mesoderm is the middle layer of the three germ layers that develops during gastrulation in the very early development of the embryo of most animals. The outer layer is the ectoderm, and the inner layer is the endoderm.Langman's Medical ...

. That is, the skin separates from the tissue of the spinal cord to allow proper formation of the

vertebral column The spinal column, also known as the vertebral column, spine or backbone, is the core part of the axial skeleton in vertebrates. The vertebral column is the defining and eponymous characteristic of the vertebrate. The spinal column is a segmente ...

. In cases of congenital dermal sinus there is a failure in this process, resulting in formation of a persistent connection between the skin and neural tissue. This manifests as a tract extending from the surface of the skin to the spinal cord lined with

stratified squamous epithelium A stratified squamous epithelium consists of squamous (flattened) epithelial cells arranged in layers upon a basal membrane. Only one layer is in contact with the basement membrane; the other layers adhere to one another to maintain structural ...

, surrounded by dermal and neurological tissue. The tract may terminate in the

deep fascia Deep fascia (or investing fascia) is a fascia, a layer of dense connective tissue that can surround individual muscles and groups of muscles to separate into fascial compartments. This fibrous connective tissue interpenetrates and surrounds the m ...

, or even make contact with neural elements. Congenital dermal sinus may form at any point along the midline of the neuraxis, however, the majority form in the lumbar and lumbosacral region (41% and 35% of cases respectively).

Diagnosis

Congenital dermal sinus is often diagnosed in

infants In common terminology, a baby is the very young offspring of adult human beings, while infant (from the Latin word ''infans'', meaning 'baby' or 'child') is a formal or specialised synonym. The terms may also be used to refer to juveniles of ...

and

children A child () is a human being between the stages of childbirth, birth and puberty, or between the Development of the human body, developmental period of infancy and puberty. The term may also refer to an unborn human being. In English-speaking ...

. Early diagnosis is important in congenital dermal sinus, so that treatment can be provided early, to prevent progression of associated complications.

Cutaneous abnormalities

Congenital dermal sinus is a tract from the surface layer of the skin, through the deeper tissues into the cranial or spinal cavity. The skin findings of this tract can include: * Pit along neuraxis * Flat capillary

hemangioma A hemangioma or haemangioma is a usually benign vascular tumor derived from blood vessel cell types. The most common form, seen in infants, is an infantile hemangioma, known colloquially as a "strawberry mark", most commonly presenting on the sk ...

Hypertrichosis Hypertrichosis (sometimes known as werewolf syndrome) is an abnormal amount of hair growth over the body. The two distinct types of hypertrichosis are generalized hypertrichosis, which occurs over the entire body, and localized hypertrichosis, w ...

Skin tag A skin tag, or acrochordon (: acrochorda), is a small benign tumor that forms primarily in areas where the Human skin, skin forms creases (or rubs together), such as the neck, armpit and groin. They may also occur on the face, usually on the ey ...

* Abnormal pigmentation * Subcutaneous

lipoma A lipoma is a benign tumor made of adipose tissue, fat tissue. They are generally soft to the touch, movable, and painless. They usually occur just under the skin, but occasionally may be deeper. Most are less than in size. Common locations inc ...

* Signs of local

infection An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmis ...

Infection

The stratified squamous epithelium of the congenital dermal sinus tract can extend to the spinal

fascia A fascia (; : fasciae or fascias; adjective fascial; ) is a generic term for macroscopic membranous bodily structures. Fasciae are classified as superficial, visceral or deep, and further designated according to their anatomical location. ...

of the dura mater or all the way to the

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...

. Thus, the congenital dermal sinus forms a point of entry for infection, this can allow for the formation of an

abscess An abscess is a collection of pus that has built up within the tissue of the body, usually caused by bacterial infection. Signs and symptoms of abscesses include redness, pain, warmth, and swelling. The swelling may feel fluid-filled when pre ...

, especially among children. Infection can then travel up the spinal cord to result in

meningitis Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, intense headache, vomiting and neck stiffness and occasion ...

, which can be fatal if left untreated.

Neurological deficit

Congenital dermal sinus is often also associated with

spinal fluid Cerebrospinal fluid (CSF) is a clear, colorless transcellular body fluid found within the meningeal tissue that surrounds the vertebrate brain and spinal cord, and in the ventricles of the brain. CSF is mostly produced by specialized ependym ...

drainage, intradural

cysts A cyst is a closed Wikt:sac, sac, having a distinct Cell envelope, envelope and cell division, division compared with the nearby Biological tissue, tissue. Hence, it is a cluster of Cell (biology), cells that have grouped together to form a sac ...

and

tethering; conveying neurological deficit. Neurological deficit can occur due to spinal cord compression from intradural

dermoid cyst A dermoid cyst is a teratoma of a cystic nature that contains an array of developmentally mature, solid tissues. It frequently consists of skin, hair follicles, and sweat glands, while other commonly found components include clumps of long hair ...

growth in the

epidermis The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and Subcutaneous tissue, hypodermis. The epidermal layer provides a barrier to infection from environmental pathogens and regulates the ...

and

dermis The dermis or corium is a layer of skin between the epidermis (skin), epidermis (with which it makes up the cutis (anatomy), cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from s ...

. Tethered spinal cord can result in

gait Gait is the pattern of Motion (physics), movement of the limb (anatomy), limbs of animals, including Gait (human), humans, during Animal locomotion, locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on s ...

difficulties and

sphincter A sphincter is a circular muscle that normally maintains constriction of a natural body passage or orifice and relaxes as required by normal physiological functioning. Sphincters are found in many animals. There are over 60 types in the human bo ...

dysfunction, as well as compressing the spine. Neurological deficits are more likely to occur where diagnosis has not been timely, allowing cysts and or infection.

Imaging

Magnetic Resonance Imaging Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and ...

(MRI) is the preferred tool for diagnostic and preoperative imaging of congenital dermal sinus. MRI allows the neural structures to be observed, visualizing the tract and its anomalies and lesions. For example, exposing tethered cord, inclusion tumors or spinal cord malformations. Observation by

X-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...

is limited in diagnosis, especially due to immature

calcification Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue,Miller, J. D. Cardiovascular calcification: Orbicular origins. ''Nature M ...

of infants less than 18 months. X-ray may be used in conjunction with MRI or sonogram images to assist preoperatively.

Treatment

Treatment of congenital dermal sinus involves complete resection of the tract as well as intradural exploration.

Prophylactic Preventive healthcare, or prophylaxis, is the application of healthcare measures to prevent diseases.Hugh R. Leavell and E. Gurney Clark as "the science and art of preventing disease, prolonging life, and promoting physical and mental health a ...

surgical removal of the congenital dermal sinus tract is beneficial for the patient, allowing neurological and bladder function to be maintained. Early surgical intervention results decreases the risk of infection and/or tumour progression – factors typically associated with delayed presentation of congenital dermal sinus. ] Intradural exploration is necessary as excision of the entire tract, as well as any of its intradural connections, reduces need for further surgical intervention. The surgical technique involves ‘removing the cutaneous lesion in ellipse’. The tract of the congenital dermal sinus must then be explored and excised, with intradural lesions dissected. If not all epithelial tissue is removed, there is a possibility for the dermoid cyst to reoccur and require further operation. Further operations are limited by postoperative and post-infection scarring.

History

Prior to pervasive use and availability of advanced methods of neuroimaging, it is possible that the rate of incidence of congenital dermal sinus has been supplemented by the incidence of coccygeal pits. Coccygeal pits are distinct from congenital dermal sinus as they are found within the

gluteal cleft The intergluteal cleft or just gluteal cleft, also known by a number of synonyms, including natal cleft and cluneal cleft, is the groove between the buttocks that runs from just below the sacrum to the perineum, so named because it forms the vis ...

, rather than above the gluteal cleft. The

caudally Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provi ...

orientated coccygeal pits are not associated with intradural pathology and do not need to be excised, unlike the cephalically oriented tracts of the congenital dermal sinus which confer great intradural pathology and require surgical intervention. While coccygeal pits occur in 4% of

neonate In common terminology, a baby is the very young offspring of adult human beings, while infant (from the Latin word ''infans'', meaning 'baby' or 'child') is a formal or specialised synonym. The terms may also be used to refer to Juvenile (orga ...

population, congenital dermal sinus is only found in 1 in 2500 live births.

References

{{Congenital malformations and deformations of musculoskeletal system Congenital disorders of nervous system Congenital disorders of musculoskeletal system Cutaneous congenital anomalies