Introduction:
In 1848, Luschka first described congenital midline cervical cleft (CMCC). However, it was not completely described until 1946, when Ombredanne explained it in his textbook on pediatric surgery. CMCC is not very common, and it can be easily diagnosed through clinical examination. However, CMCC can be confused with a thyroglossal duct or branchial anomaly. Surgery is the treatment option for congenital midline cervical cleft. Early and prompt intervention is required to avoid any serious complications of longstanding congenital midline clefts like impairment of mandibular growth or limitation of neck extension.
Imaging is usually required to differentiate CMCC from other lesions or to examine the existence of other lesions. Magnetic resonance imaging or MRI is considered the best technique to determine the extent of the cleft and associated ENT (ear, nose, and throat) anomalies necessary for presurgical planning.
What Is Congenital Midline Cervical Cleft (CMCC)?
Congenital midline cervical cleft (CMCC) is a rare congenital anomaly that is seen during embryogenesis due to failure of fusion of the first and second branchial arches. It is mostly reported sporadically in Caucasian females and has a female-to-male ratio of 2:1. The cleft is found in the midline of the anterior neck, between the mandible and the sternum. It can be seen as a midline defect of the anterior neck skin along with a sinus or skin projection or as a subcutaneous fibrous cord. At the time of birth, the area has a discharge and is covered by thin, desquamating epithelium in most cases. During the next few months, the epithelium toughens and becomes dry. Histologically, the congenital midline cervical cleft consists of a fibrous cord, skeletal muscle, and exocrine tissues.
Midline congenital cervical malformations show an incidence of one to two percent that has been described in numerous cases, including ectopic thyroid, the absence of thyroid or thyroglossal duct cyst, branchial cyst, ectopic bronchogenic cyst, midline hemangioma, midline abdominal web, clefts of the lip, tongue, chin, mandible, or sternum, absence of hyoid bone or thyroid cartilage, ectopia cordis, and rare congenital cardiac anomalies. In case of inadequate repair or as the child grows, the fibrous cord becomes more evident and might lead to contractures of the torticollis, neck, or limited extension.
The first-line imaging technique for other cervical anomalies is ultrasound; however, for complete imaging of the cervical tract and possible associated anomalies with magnetic resonance imaging (MRI). MRI can be used for presurgical planning.
A bony prominence of the mandible might be palpated due to traction on the mandible, and exostosis of the mandible or sternum can be observed on radiographs and MRI. Therefore an early and prompt diagnosis is essential for avoiding these complications.
What Are the Clinical and Imaging Features of Congenital Midline Cervical Cleft?
The midline cervical cleft is usually detected at the time of birth as a thin vertical erythematous band of skin with a superior nipple-like projection. It can be present anywhere across the midline from the chin to the suprasternal notch. A blind-ending sinus tract associated with midline cervical cleft in the caudal aspect might exhibit occasional minimal secretion. The midline cervical cleft can heal by scarring, leading to a fibrous cord formation that might cause a neck contracture and gradually lead to micrognathia (an undersized jaw) in early childhood. Moreover, certain reports have shown defects in the mandible, lower lip, chin, and tongue.
Before the widespread use of ultrasound and MRI, in advanced cases, radiographs of the neck usually showed bony spurring at the mandible due to traction from the underlying fibrous cord. Ultrasound of the neck shows a non-vascular, blind-ending sinus tract from the skin surface. The thyroid gland is generally normal. MRI is helpful in identifying the lesion and its course to other lesions like thyroglossal duct cysts or branchial cleft anomalies.
How Is Congenital Midline Cervical Cleft Treated?
Congenital midline cervical cleft is treated surgically by resectioning the skin tag and fibrotic tissue, along with the closure of the soft tissue defect through Z-plasties (a transposition flap technique commonly used to revise scars in plastic and reconstructive surgery). Although there is no general agreement on the age of treatment, surgical intervention is advised at the initial stage before scarring leads to neck webbing, contracture, or mandibular hypoplasia (the underdevelopment of the mandible or the lower jaw). Good outcomes are seen after multiple series of Z-plasties.
However, recurrent cases have been documented. For treating infections or abscesses of congenital midline cervical clefts, antibiotics have to be administered. Treatment generally includes surgical excision and defect closure. The exact technique and time of surgery vary, but most of the research supports the earliest intervention for the desired results. Z-plasty incisions are advised, particularly in cases of delayed symptoms. To prevent the development of scar and subsequent cicatrices (scar) contractures. Primary anastomosis (a surgical connection between two structures) is used in patients with small clefts.
What Is the Differential Diagnosis of Congenital Midline Cervical Cleft?
Differential diagnosis of congenital midline cervical cleft includes
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Branchial cleft anomalies.
A thyroglossal duct cyst is a midline T2 hyperintense lesion that might show faint peripheral enhancement with a characteristic cystic appearance. It is usually more prominent in the neck, being more midline when related to the hyoid and generally lateral in the infrahyoid neck. Further, a thyroglossal duct cyst is not often associated with the sinus tract unless it is superinfected. Second and third branchial cleft cysts or pyriform sinus fistulae are usually off midline in the lateral neck.
Conclusion:
Congenital midline cervical cleft is a rare condition often diagnosed clinically. However, the radiologist might have to evaluate this problem to further characterize anatomy and rule-out other differential conditions. Diagnosing an anterior cervical midline skin defect with an underlying blind-ending sinus tract shows peripheral contrast enhancement on a magnetic resonance that allows prompt surgical intervention to prevent future complications. In summary, a congenital cervical cleft is a rare anomaly. A small amount of these is associated with other midline anomalies of the head, neck, and chest. Magnetic resonance imaging (MRI) is a useful technique for demonstrating the spread of the cleft and diagnosing if there are any other associated problems, and it might be useful for pre-planning the surgical repair.
