| disease | Cervical Cystic Lymphangioma |
| alias | Cystic Hygroma |
Lymphangioma is not a true tumor but a congenital benign hamartoma. It results from tumor-like malformations caused by the isolation of primitive lymphatic sacs from the lymphatic system during embryonic development. Approximately half of these cases are present at birth, and over 90% are detected before the age of 2. The incidence is roughly equal between males and females. Cystic lymphangioma most commonly occurs in the neck and is also known as a cystic hygroma. It is the most frequently observed clinically, accounting for about 3/4 of cases, with the rest found in the axilla, mediastinum, retroperitoneum, and pelvis.
bubble_chart Pathological Changes
During the embryonic stage, the fusion of mesodermal clefts in the venous plexus forms large primitive lymphatic sacs, which drain into the central venous system. Later, these lymphatic sacs gradually regress or develop into a lymphatic vessel system parallel to the veins. If the primitive lymphatic sac fails to connect with the venous system, a cystic lymphangioma may form. If it does not communicate with the main trunk of the lymphatic system, a cavernous lymphangioma may occur. If a small number of lymphatic sacs become isolated during the formation of the lymphatic system, a simple lymphangioma may develop. Because the jugular lymphatic sac forms earliest and is the largest, cystic lymphangiomas most commonly occur in the neck.
Lymphangiomas are composed of proliferating, dilated, and structurally disordered lymphatic vessels that can grow invasively into surrounding tissues. Based on their morphology and distribution, they can be divided into three types:
(1) Simple lymphangioma: Consists of dilated, irregular capillary lymphatic plexuses with minimal stroma, primarily occurring in the skin, subcutaneous tissue, and mucosal layers.
(2) Cavernous lymphangioma: Lymphatic vessels expand into sinus-like structures filled with lymph fluid, forming multilocular cystic cavities with abundant surrounding stroma. The lesions may involve the skin, mucosa, subcutaneous tissue, and deep structures such as muscles, retroperitoneum, and mediastinum.(3) Cystic lymphangioma: Characterized by large cystic cavities, which may be unilocular or multilocular and interconnected, lined with endothelial cells and with minimal stroma.
In clinical practice, lymphangiomas are often mixed types. If a lymphangioma contains hemangioma tissue, it is referred to as a lymphangiohemangioma.
bubble_chart Clinical Manifestations
The presence of a giant cystic hygroma in the neck can cause difficulty in fetal delivery. Generally, a soft cystic mass can be observed on the lateral side of the neck shortly after birth, with obvious fluctuation and a positive transillumination test. Its boundaries are often unclear, it is not easily compressible, and there is no pain. The tumor is not adherent to the skin, grows slowly, and shows no significant change in size. However, it is prone to complications such as infection, which can be difficult to control. Intracystic hemorrhage may also occur, causing sudden enlargement of the tumor, increased tension, and a bluish-purple color. Compression of surrounding organs can lead to corresponding symptoms. Some tumors may extensively invade the floor of the mouth, throat, or mediastinum, compressing the trachea or esophagus, resulting in respiratory distress and dysphagia, which can even be life-threatening.
Some lymphangiomas may spontaneously thrombose and regress during their development, or after infection, when the endothelial cells of the cyst wall are destroyed, they may resolve on their own once the infection is controlled.
1. A cystic mass in the posterior cervical triangle, characterized by spreading growth to surrounding areas (supraclavicular/infraclavicular, floor of the mouth, paratracheal/esophageal, and mediastinum), often with indistinct boundaries. Most commonly seen in infants and young children. It may be massive at birth or gradually enlarge.
2. The cyst is soft, generally non-compressible, and translucent. The overlying skin is normal and not adherent.
3. The contents are pale yellow and transparent or chylous, occasionally bloody. Microscopically, a large number of lymphocytes containing cholesterol crystals can be observed.
4. When the cyst involves the floor of the mouth, tongue, or pharynx, it may cause speech, respiratory, or swallowing difficulties. If located in the supraclavicular region, it may compress the brachial plexus, leading to motor dysfunction or muscle atrophy. There may be seasonal epidemic duct displacement.
bubble_chart Treatment Measures
(1) Expecting Spontaneous Healing For small and localized lymphangiomas that do not affect function or aesthetics, treatment may not be necessary, as some lymphangiomas have a tendency to regress naturally. For lesions that are more extensive but show no signs of respiratory or swallowing difficulties or other severe complications, observation and follow-up for 1–2 years may be appropriate. If no regression or even enlargement is observed, treatment should then be initiated.
(2) Injection Therapy In the past, local injection of sclerosing agents was considered ineffective for treating lymphangiomas. In recent years, the use of the antitumor drug bleomycin for local injection therapy has yielded satisfactory results, with complete regression or significant shrinkage achieved in up to 70% of cases. This may be due to its dual effects of inhibiting the growth of lymphatic endothelial cells and chemically stimulating stromal fibrosis. Histologically, it is less effective for types with more stroma, such as simple and cavernous lymphangiomas, but more effective for types with less stroma, such as cystic hygromas. Practical applications have confirmed this.
Recent reports describe the use of OK-432 (picibanil, a preparation of hemolytic streptococci) for local injection therapy. One clinical unit (1 ke) of OK-432 is dissolved in 10 mL of saline, and an equal volume of the solution is injected into the tumor cavity after aspirating the fluid. The maximum single dose should not exceed two clinical units, and additional injections of 1–2 units may be given after 2–4 weeks of observation. In a group of 22 cases, 14 showed complete regression after 1–3 injections within 2–3 months, 6 showed significant shrinkage, and 2 showed no response. Side effects include local inflammatory reactions, swelling lasting 3–5 days, and transient fever. This method avoids the risk of pulmonary fibrosis associated with bleomycin.
Because injection therapy is relatively simple, causes minimal tissue damage, and avoids the severe complications that may arise from surgery—which often fails to achieve complete removal—it can be considered the first-line treatment for cystic lymphangiomas.
(3) Surgical Treatment Although surgical excision remains the primary treatment for lymphangiomas, it is no longer recommended without clear indications for any type of lymphangioma. Surgery is indicated for cervical lymphangiomas that extend into the mediastinum or thoracic cavity, potentially causing respiratory or feeding difficulties, and for cases unresponsive to injection therapy. Surgery should not be performed during active infection, which must first be controlled. Intracystic hemorrhage is not a contraindication for surgery.
The actual extent of cystic lymphangiomas often exceeds initial estimates, making complete surgical removal challenging. Careful dissection of critical structures such as nerves and blood vessels in the neck is essential to prevent complications like facial nerve palsy, lingual nerve injury, recurrent laryngeal nerve injury, or phrenic nerve injury, which may lead to respiratory difficulties or hoarseness. For residual cyst walls, application of 0.5% iodine tincture can destroy endothelial cells to prevent recurrence.
It should be differentiated from thyroglossal duct cyst, branchial cleft cyst, dermoid cyst, and lipoma.
