Dermoid cysts: Benign, slow-growing lesions containing dermal components, may include hair, teeth, and skin glands.
Epidermoid cysts: Contain only epidermal tissue and keratin debris.
Common Locations:
Forehead, lateral corner of the eyebrow, anterior fontanelle, and postauricular space.
Symptoms:
Usually asymptomatic, but may increase in size over time, becoming osteolytic.
Diagnosis and Treatment:
Clinical examination is often sufficient for scalp lesions.
Imaging studies (e.g., ultrasound) are critical for midline lesions, such as communicating cephaloceles.
Treatment involves surgical excision.
Lymphadenopathy
Presentation:
Enlarged lymph nodes, typically in anterior cervical triangle, often presenting as small, mobile, discrete clusters.
Usually found along the sternocleidomastoid muscle border.
Diagnosis:
A detailed history and physical exam usually suffices to determine the need for surgery.
Ultrasound helps identify nodes with central necrosis requiring surgical intervention.
Fixed, non-tender, progressively enlarging supraclavicular nodes with constitutional symptoms (night sweats, weight loss) raise suspicion for more serious etiologies, warranting chest radiography to detect mediastinal adenopathy.
Common Causes:
Respiratory infections (e.g., adenovirus, influenza virus, respiratory syncytial virus) cause acute bilateral cervical lymphadenitis, usually treated by observation.
S. aureus and Group A streptococcus are responsible for most cases of acute pyogenic lymphadenitis.
Special Conditions:
Cat-scratch disease:
Caused by Bartonella henselae, presenting as painful regional lymphadenopathy.
Diagnosed via polymerase chain reaction (PCR) assay of lymph node biopsy; usually self-limited.
Nontuberculous mycobacterial infection:
Presents as fluctuant nodes with violaceous skin.
Diagnosis confirmed by positive cultures for nontuberculous acid-fast bacilli.
Treatment involves surgical excision, as these bacteria are resistant to conventional chemotherapy.
Cystic Hygroma
Definition:
A multiloculated cyst lined by endothelial cells, caused by lymphatic malformation.
Common Sites:
Posterior neck region, as well as axillary, mediastinal, inguinal, and retroperitoneal regions.
Approximately 50% are present at birth.
Clinical Features:
Soft cystic masses that can distort surrounding structures, including the airway.
Large neck masses in fetuses may cause airway obstruction at birth, requiring prenatal ultrasound and fetal MRI.
Management:
Severe cases may require a carefully coordinated ex-utero intrapartum treatment (EXIT) procedure at birth.
Prone to infection and hemorrhage.
MRI is useful to map the extent of the lymphatic channels.
Treatment:
Complete surgical excision with isolation and ligation of lymphatic branches is ideal.
Avoid aggressive dissection (blunt/electrocautery) to prevent recurrence or infection.
If complete excision is not feasible, sclerosing agents (e.g., bleomycin, doxycycline, OK-432) are effective nonsurgical alternatives.
Thyroglossal Duct Cyst
Definition: A midline cystic neck lesion often found in toddlers, commonly originating from remnants of the thyroglossal duct.
Embryology:
Arises from the thyroid diverticulum at the foramen cecum, which descends through the central hyoid bone.
The thyroglossal duct connects the base of the tongue to the thyroid gland during embryonic development.
Normally, the thyroglossal duct regresses as the thyroid descends to its pretracheal position. Failure of this regression can lead to the formation of a thyroglossal duct cyst.
Locations:
Can occur anywhere from the base of the tongue to the thyroid gland, but most often found at or just below the hyoid bone.
Complications:
Lingual thyroid can occur if the thyroid fails to descend properly, leaving no thyroid tissue in the neck.
Diagnosis:
Ultrasound or radionuclide imaging can be used to identify ectopic thyroid tissue.
Treatment:
The Sistrunk procedure is the gold standard treatment, involving the complete excision of the cyst along with the central portion of the hyoid bone and the cyst’s tract up to the base of the tongue.
Failure to completely excise the tract may lead to a 40-50% recurrence rate.
Branchial Cleft Remnants
Definition: Congenital lateral neck masses that arise from branchial cleft anomalies, including cysts, sinuses, or fistulas due to the failure of branchial arch structures to regress during embryonic development.
Embryology:
Derived from six pairs of branchial arches and their associated clefts and pouches.
The location of these remnants guides the surgical approach and indicates their embryologic origin.
Clinical Presentation:
Sinuses, fistulas, or cystic masses that may present as continuous mucoid drainage, infected cysts, or palpable cartilaginous lumps.
Dermal pits or skin tags may also be present.
Types:
First branchial cleft anomalies:
Typically located around the ear or upper neck.
Fistulas may pass through the parotid gland and course near the facial nerve.
Second branchial cleft anomalies (most common):
External ostium is found along the anterior border of the sternocleidomastoid muscle.
Fistula tract may extend from the carotid sheath to the tonsillar fossa, often requiring stepladder counter-incisions for complete excision.
The tract courses near the hypoglossal and glossopharyngeal nerves, behind the posterior belly of the digastric and stylohyoid muscles.
Third branchial cleft remnants:
Usually located in the suprasternal notch or clavicular region.
Typically present as cysts rather than fistulas and can descend into the mediastinum.
These often contain cartilage and may present as a firm mass or subcutaneous abscess in toddlers or older children.