No need for panic with MANIC
By Warren R. Heymann, MD
March 22, 2018
As a medical student, I would panic over embryology of the neck. I never quite understood the development and anomalies of branchial arches or the migration of the thyroid anlage from the foramen cecum; yet I knew that as a clinician, it would be important to comprehend the differential diagnosis of neck lesions. Parents may worry, having questions and concerns about imaging studies, potential associations, and possible surgery.
The standard differential diagnosis of defects of the anterior midline fusion plane includes thyroglossal duct cysts (TDC), bronchogenic cysts (BC) and congenital midline cervical clefts (CMCC).
TDCs are the most frequently encountered congenital abnormality of the neck, accounting for up to 75% of midline lesions in children. They may be noted in all age groups. They classically present as indolent, asymptomatic soft masses that move upward with tongue protrusion or swallowing, although restricted movement does not rule out the diagnosis. Because of its embryologic development, lesions may be intralingual, suprahyoid and/or submental, juxtahyoid, or suprasternal. Ultrasound is considered the ideal initial investigation of TDCs; CT scans or fine needle aspiration may also be considered for diagnosis. Thyroglossal duct carcinomas occur in approximately 1% of TDCs. (1) Such cancers are exceedingly rare in the pediatric population, and all have been papillary carcinomas in this age group. Just as for the surgical approach for standard TDCs, the Sistrunk procedure (removal of the cyst, tract, and portion of the hyoid bone) is considered the treatment of choice for patients with thyroglossal duct cyst carcinomas. (2)
BCs are rare congenital malformations of ventral foregut development. They are located in the thorax in more than half of patients, but may be present from the oral cavity to the mediastinum or lung parenchyma. Dermatologists will usually note them in the mid-cervical region. Ultrasound, CT, and MRI are useful imaging studies, although a definitive diagnosis can only be obtained following surgical excision, where a pseudostratified columnar epithelium will be observed histologically. (3)
CMCCs are rare developmental abnormalities of the ventral neck consisting of red, atrophic skin at the ventral midline neck, associated with a fibrous cord, a cephalic nipple-like skin projection, and caudal sinus tract. The cleft can extend from the submental region to the suprasternal notch. The embryopathology remains unclear, although CMCC is considered result from a failure in mesodermal fusion of the first and second branchial arches on the midline of the neck between gestational weeks 3 and 4. Associated cysts may occur because of the presence of seromucinous glands in the sinus tract (and may not be BCs or TDCs). Although rare reports of associated anomalies exist in the literature (minor renal malformation, congenital heart disease [atrial septal defect], lack of a hyoid bone), CMCC is considered an isolated malformation not requiring an exhaustive imaging assessment beyond an ultrasound. Surgical excision of the entire lesion may be considered for aesthetic reasons or to prevent the development of a cervical contracture. (4)
Walsh et al detailed seven patients with of small, superficial midline neck cysts appearing as giant milia without evidence of underlying anomalies or associated defects. They termed these lesions midline anterior neck inclusion cysts (MANICs). MANICs appear to be superficial congenital developmental defects occurring along the anterior midline fusion plane. The characteristic and consistent location (on the lower neck on the sternal notch, just above the manubrium) in all cases, and their congenital presentation suggest a developmental anomaly at that site. MANICs were not associated with other congenital or developmental defects. Shave or snip removal, surgical excision, or even curettage can be curative, and spontaneous regression may even occur (as observed in one patient). (5)
In conclusion, with careful thought (without panic), lesions of the anterior neck presenting in childhood can be addressed diagnostically and therapeutically. For superficial suprasternal milia-like lesions, MANIC should be at the top of the list.
Point to remember: MANICs are benign, congenital, suprasternal superficial milia-like lesions not requiring further evaluation.
1. Chou J, et al. Thryoglossal duct cysts: anatomy, embryology, and treatment. Surg Radiol Anat 2013; 35: 875-81.
2. Thompson LDR, et al. Thyroglossal duct cyst carcinomas in pediatric patients: Report of two cases with a comprehensive literature review. Head Neck Pathol 2017; 11: 442-9.
3. Lee DH, et al. Bronchogenic cyst in the head and neck region. J Craniofac Surg. 2017; 28: e303-e305.
4. Achard S, et al. Congenital midline cervical cleft: A retrospective case series of 8 children. Int J Pediatr Otorhinolaryngol 2016; 81: 60-4.
5. Walsh R, et al. Midline anterior neck inclusion cyst: A novel superficial congenital developmental anomaly of the neck. Pediatr Dermatol 2018; 35: 55-8.
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