Cysts of the neck



Cysts of the neck

|Midline cyst |Lateral cyst |

|submental dermoid cyst. |cystic hygroma. |

|thyroglossal cyst. |plunging ranula. |

|subhyoid bursitis. |branchial cyst. |

|cyst in the thyroid isthmus. |cyst in thyroid lobe. |

|cold abscess in submental or prelaryngeal L.N. |cold abscess. |

|Laryngeocele. |pharyngeal pouch. |

|Suprasternal dermoid. |pneumatocele. |

I. dermoid cyst:

Definition : cyst which is due to continued epithelial growth under the skin.

Types:

1- Sequestration dermoid cyst:

occurs during development where some epithelial cells become sequestrated beneath the lines of fusion between the dermatomes. The cyst will be formed later in life.

2- Tubulodermoid:

due to distension of embryonic duct remanent as:

• thyroglossal cyst (from thyroglossal duct)

• branchial cyst (from cervical sinus)

• post anal dermoid cyst.

3- Implantation dermoid cyst:

occurs commonly in the fingers, palm, sole and in relation to skin wound. They are due to puncture wounds (pin prick) in which some of the epithelial cells are implanted into the subcutaneous tissue which will grow forming a cyst.

4- Teratomatous dermoid cyst:

It is a benign form of teratoma. Usually occurs in the testis and ovary. It is due to inclusion of embryonic toti potent cells in the ovary during development. The wall is made of skin containing teeth, hair, bone and cartilage.

Sequestration dermoid cyst:

• Although it is congenital yet it may not appear except late.

• It occurs at the line of fusion.

o Neck and trunk: midline anteriorly and posteriorly.

o Face: junction between frontonasal-maxillary and mandibular process.

o Limbs: no line of fusion as the limbs develop as bud.

• Pathology: the cyst is small lined by squamous epithelium contains sebaceous material and covered by fibrous tissue.

• Complications:

o Infection leading to abscess.

o Rarely external angular dermoid in the face may have an intracranial extension.

o Malignant change is very rare.

• Types of sequestration dermoid cysts:

a- External angular dermoid: occurs at the lateral side of the orbital margin at the line of fusion of the frontonasal and maxillary process.

b- sublingual dermoid cyst: (submental) in the midline of the neck either:

1- Inframyelohyoid cyst: below the myelohyoid muscle. Does not move with protrusion of the tongue nor with deglutition.

2- supramyelohoid cyst: bulges in the floor of the mouth above the myelohoid muscle.

c- Suprasternal dermoid cyst: in the midline at the suprasternal notch.

• Clinical picture of dermoid cyst: well defined cystic swelling with smooth surface. Rounded or oval in shape, not tender unless inflamed, mobile over the deep structures. The skin overlying could be separated from the swelling. The cyst in not compressible nor translucent.

• Treatment:

o Excision.

o If infected it is only incised and drained.

o If it has an intracranial extension it is left until adulthood when the bones close and the stalk between the two partws of the cyst is obliterated then the subcutaneous part is excised.

II. Thyroglossal cyst:

It is the commenest midline neck cyst.

The thyroglossal tract arises from the foramen caecum in the tongue at the junction between the anterior 2/3 and posterior 1/3 then descends downwards either infront or inside the hyoid bone then passes slightly upwards behind the hyoid bone then descends downwards again to form the thyroid isthmus and the medial portion of the thyroid lobes. The duct atrophies at the 6th week if it does not atrophy it persists as a thyroglossal duct forming the thyroglossal cyst..

• Pathology:

Males and females are equally effected. The age range from 4 months to 70 years. 90% are in the midline. 10% are to one side of these 95% on the left side and 5% on the right side.

The site incidence:

Prehyoid 75%.

Thyroid cartilage 15%.

Suprahyoid 5%

Cricoid 4%

Base of the tongue 1%.

• Clinical picture:

Painless swelling moving with protrusion of the tongue. The cyst is mobile and if low in the neck the subcutaneous tract could be felt. Cyst at the base of the tongue may cause dysarthria and should be differentiated from lingual thyroid by thyroid scan.

• Complications:

Infection leading to abscess.

Fistula: thyroglossal fistula is never congenital it is due to either abscess in a thyroglossal cyst or incomplete removal.

• Treatment:

Sistrunk operation where we remove the cyst, all the tract, the central part of the hyoid bone and part of the base of the tongue.

III. Branchial cyst:

Four grooves, branchial cleft and the intervening bars are the branchial arches.

It arises from vestigial remnant of the 2nd branchial cleft. The cyst contains mucoid fluid with many cholesterol crystals. The wall is lined with epithelial tissue and contains lymphoid tissue.

• Clinical picture

Usually at the age of 20 years as a slowly growing painless swelling at the upper lateral part of the neck between upper and middle third which is partially undercover the anterior border of the sternomastoid. It transilluminates.

• Complications: infection which is treated by antibiotics - branchial fistula - branchiogenic carcinoma.

• Treatment by complete excision reaching the deep structures near the external auditory meatus.

N.B.: the branchial fistula may be congenital due to persistence of 2nd branchial cleft. It occurs at the lower 1/3 of the anterior border of the sternomastoid. The inner opening is just behind the tunsil or may be blind (sinus). It may also be acquired due to infection or incomplete removal of a branchial cyst. It discharge mucoid or mucopurulent material. It is treated by complete excision via transverse neck incision.

IV. Subhyoid bursitis:

Inflammation of the subhyoid bursa giving a cystic transverse swelling below the hyoid bone moving with deglutition.

V. Laryngeocele:

Occurs in wind instruments players due to herniation of the laryngeal mucous membrane through the thyrohyoid membrane. It forms a tense cystic resonant translucent swelling which is compressible and enlarge when the patient blow and close the nose.

VI. Pneumatocele:

Herniation of the lung apex through the sibson fascia (suprapleural membrane) which is attached between the transverse process of the 7th cervical vertebrae and the inner border of the 1st rib. It gives a compressible resonant swelling at eh supraclavicular region specially on straining.

VII. Cystic hygroma:

Due to congenital lymphatic anomaly. Where the lymphatic spaces have afferent without efferent vessels.

It appears at birth commonly at the lower part of the neck in the posterior triangle but it may arise in the groin, mediastinum or axilla.

It is brilliantly transleuscent cystic swelling which is partially compressible.

Complications: infection, respiratory obstruction, obstructed labour.

Treatment: better at 2 years by excision but if causing respiratory obstruction aspiration is done if failed tracheostomy.

VIII. Plunging ranula:

It is a buccal ranula which has a deep extension in the neck and appears below the mandible.

A ranula is a retention cyst that arises from the glands in the floor of the mouth (glands of Balandin and Nuhn). It also may be due to extravasation from the sublingual gland.

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External auditory meatus

2nd

3rd

4th

Normally

disappear

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