Cystic lesions of the head and neck can be caused by a wide variety of conditions, including congenital anomalies, inflammation, infections, or neoplastic growths. In infants and children, cystic lesions are typically congenital, while in adults, the likely cause is inflammatory or neoplastic. Common cystic lesions in the head and neck include sebaceous cysts, dermoid cysts, dental/dentigerous cysts, mucous retention cysts, epiglottic and thyroglossal cysts, and branchial cleft cysts.

1. Nasal Dermoid Cyst A rare developmental anomaly resulting from the incomplete obliteration of neuroectoderm in the frontonasal region, a nasal dermoid can present as a cyst, sinus, or fistula and may have an intracranial extension. The incidence is approximately 1 in 30,000 live births. • Case Presentation: An 18-year-old female presented with a slowly enlarging soft, cystic swelling at the root of her nose for one year, causing a cosmetic deformity. Examination showed no punctum or hair follicle. A CT scan of the paranasal sinuses (PNS) revealed no intracranial extension. • Treatment: Surgical excision is the only treatment. The approach, whether local or combined, depends on the extent of the lesion. 2. Post-Auricular Dermoid Cyst Post-auricular (P/A) dermoid cysts are a common condition but are rare in the P/A area. They are caused by the entrapment of epithelium between the developing squamous parts of the temporal and parietal bones. Patients often seek treatment for cosmetic reasons as the cyst size increases. Differential diagnoses include lipoma, P/A lymphadenitis, and sebaceous cyst. • Case Presentation: A 30-year-old female had a 2x2 cm, smooth, mobile, non-tender swelling in the right post-auricular area that had been gradually enlarging for two years. There was no punctum or signs of inflammation. • Treatment: Surgical excision was performed under local anesthesia, and the lesion had to be sharply dissected from an attachment to the mastoid bone. The histopathological report confirmed the cyst wall was lined with keratinized squamous epithelium and contained hair follicles and sebaceous glands. 3. Nasolabial Cyst A rare, non-odontogenic lesion, the nasolabial cyst can be found in the nasal vestibule, canine fossa, and sublabial region. It is also known as a Klestadt cyst, nasoalveolar cyst, or nasal vestibule cyst. It occurs in less than 1% of jaw cysts and arises from the proliferation of entrapped epithelium of the nasolacrimal duct. • Case Presentation: A 58-year-old female presented with fullness and pain in her right nasolabial sulcus for one year, which had increased in size over six months. She also complained of right-sided nasal obstruction. Examination showed a 2x2 cm soft cystic swelling that narrowed the nasal vestibule and was palpable in the gingivo-buccal sulcus. • Treatment: A nasolabial cyst should be considered in the diagnosis of a painless, soft-tissue vestibular swelling. The most effective treatment is complete excision via a sub-labial approach to prevent recurrence and for cosmetic purposes. Histopathology revealed the cyst was lined by pseudo-stratified ciliated columnar epithelium. 4. Dentigerous Cyst A dentigerous cyst is a type of odontogenic cyst that forms around the crown of an unerupted or impacted tooth. It can manifest as a painless swelling, a palpable mass, or mimic sinusitis. Radiology is helpful for diagnosis, but histopathological confirmation is needed after excision. • Case Presentation: A 24-year-old overweight female presented with a chubby face, puffiness, and pain in her right cheek for three months, along with yellowish discharge from her right nasal cavity. The right third maxillary molar was missing. An X-ray of the paranasal sinuses showed complete opacification of the right maxillary sinus. A CT scan revealed a unilocular, well-defined cystic lesion in the right maxillary sinus with an unerupted tooth embedded in the cyst wall. • Treatment: The treatment is surgical excision, typically via a Caldwell-Luc approach. Histopathology confirmed a dentigerous cyst. 5. Epiglottic Cyst An epiglottic cyst is a rare, benign retention cyst of the larynx. Its pathogenesis involves the obstruction of ducts of the mucous glands or minor salivary glands in the vallecula and at the base of the tongue. While often asymptomatic, it can cause symptoms such as stridor, difficulty swallowing, hoarseness, throat irritation, and chronic cough. • Case Presentation: A 42-year-old female singer presented with a four-month history of a cough, snoring, and throat irritation. An examination with a tongue depressor showed a yellowish, globular, partially mobile swelling near the base of the tongue in the right half of the vallecula. Video laryngoscopy identified the lesion arising from the lingual surface of the epiglottis. • Treatment: Treatment involves excision of the entire cyst or marsupialization. The patient underwent excision via microlaryngeal surgery. The histopathology report confirmed it was an epiglottic cyst. 6. Branchial Cleft Cyst Branchial cleft cysts are embryonic anomalies caused by the incomplete involution of branchial cleft structures during development. These cysts are pathological remnants of epithelium-lined cavities that can present as cysts, fistulae, sinus tracts, or cartilaginous remnants on the anterior neck and upper chest. • Case Presentation: A 7-year-old female child had a smooth, non-tender, and fluctuant neck swelling at the lower border of the right sternocleidomastoid muscle (SCM). The cyst had ruptured spontaneously once. • Treatment: The standard treatment is surgery via a step-ladder incision. Methylene blue is injected to visualize the tract, and a Prolene suture can be used to facilitate dissection. 7. Thyroglossal Cyst Thyroglossal duct cysts are embryonic in origin, arising from a remnant of the thyroglossal duct along its path in the neck. These cysts are commonly seen in preschool children (25%), children up to 10 years old (40%), and adults around 20 years old (33%). Before performing an excision, it's essential to rule out the possibility of a midline ectopic thyroid. • Case Presentation: A 20-year-old college student presented with a right-sided, submandibular neck swelling that had been present for one year. The swelling gradually increased to the size of a small lemon and caused discomfort while swallowing, in addition to being cosmetically unacceptable. Investigations included routine blood tests, thyroid function tests, ultrasound, and FNAC of the swelling. • Treatment: The standard and safe surgical procedure is the Sistrunk's Operation, which involves the complete excision of the cyst up to the base of the tongue, including the central part of the hyoid bone. Careful dissection and removal of the hyoid bone are crucial to prevent recurrence.

Cystic lesions of the head and neck present a diagnostic challenge due to their diverse etiologies. A thorough understanding of their clinical presentation, pathophysiology, and appropriate diagnostic tools is vital for effective management. Surgical excision remains the primary mode of treatment for most of these conditions, with specific approaches tailored to the type and location of the cyst.

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