Haifa Israel.

Embryology
Four pairs of branchial arches develop in the fourth gestational week as ridges on the lateral cervico-facial area. These arches are separated by four paired clefts and pouches.

1. The first pharyngeal pouch gives rise to the eustachian tube, middle ear and mastoid cells.
2. The second pouch forms the supratonsillar fossa.
3. The third pouch develops into the thymus gland and upper parathyroid glands while
4. The fourth pouch gives rise to the lower parathyroid gland and part of the thyroid gland (1).

Brachial remnants (cysts, fistula, skin tags, chondrocuteneous vestige) are developmental anomalies of this system. Cervical chondrocutaneous branchial remnants are usually embedded in the anterior border of the sternocleidomastoid muscle and appear as  skin tags. They probably originate from the second branchial arch.

Clinical manifestation
Atlan et al (2) presented a detailed review of 20 children treated during a 13-year period. Seventeen were true chondrocutaneous branchial remnants and 3 were skin tags associated with a thyroglossal duct.
Of the 17 true cases, 12 were on the left side of the neck and 6 on the right. A single patient presented with two lesions. A male predominance was noted (11 of 17).

Associated anomalies

Were noted in 76 percent of cases. This included anomalies of the auditory, respiratory, orogastrointestinal, genitourinary, cardiovascular, musculoskeletal and visual systems.

Differential diagnosis

Branchial cyst/fistula ,thyroglossal cyst/fistula , hemangioma, dermoid tumor, Goldenhar syndrome.

Current cases
Presented are two fetuses of low risk pregnancies in whom we observed cervical echogenic elongated skin tags at 15 weeks gestation.
1. Male fetus with complete situs inversus.(unilateral left).

2. Female fetus with left persistent superior vena cava and ventricular septal defect.(bilateral).Figures B, C, D

Comment
Skin tags may be observed in early gestation (3). A detailed survey of all fetal organs should be done because of the high incidence of associated anomalies.

References
1. Doi O, Hutson JM, Myers NA, McKelvie PA. Branchial remnants: a review of 58 cases. J Pediatr Surg 1988;23(9):789-792.
2. Atlan G, Egerszegi EP, Brochu P, Caouette-Laberge L, Bortoluzzi P. Cervical chrondrocutaneous branchial remnants. Plast Reconstr Surg 1997;100(1):32-39.
3. Bronshtein M, Zimmer EZ:Transvaginal Sonography of the normal and abnormal fetus:    Parthenon Publishing 2001: Page 76