Lymphangioma

Ronald Thant, M.D.

T. Ben Ami, MD

Children's Memorial Hospital

Abstract

3 day old ex-premie with a mediastinal/pericardial mass seen on echocardiogram.

Keywords

Lymphangioma, cystic hygroma, congenital lymphatic malformation, mediastinal mass, 1328 CT


Publication Date: 2007-05-25

History

3 day old ex-premie with a mediastinal/pericardial mass seen on echocardiogram.

Findings

CT – Low attenuated soft tissue mass within the middle mediastinum, surrounding the aorta and pulmonary arteries. It is difficult to tell with certainty if it extra- or intrapericardial. No definite enhancement except for mild enhancement of the thin walled septa. The mass extends superiorly to the origin of the right brachiocephalic artery and posteriorly to the esophagus and descending aorta.

US - Infiltrative mass seen at the superior aspect of the heart. The mass comprises of numerous anechoic cysts of variable size as well as echogenic components likely representing microscopic cysts. Real time imaging showed the mass to be deformed by vascular pulsation rather than restricting vascular motion. It insinuates around the ascending aorta and pulmonary trunk. Color Doppler did not demonstrate any internal vascularity.

DDx

Thymic cyst, pericardial cyst, bronchogenic cyst, and cystic teratoma.

Discussion

Lymphangiomas can be classified based on the size of the lymphatic spaces as simple, cavernous, or cystic. Simple lymphangiomas, which are the least common are composed of capillary sized, thin-walled lymphatic channels with considerable amount of connective tissue stroma. Cavernous lymphangiomas are composed of actively growing, dilated lymphatic channels with cysts of intermediate size. Cystic lymphangiomas, most common, are single or multiple cystic lymphatic channels varying in size from a few mm to >10 mm. All three are benign, slow-growing tumors and assumed to result from congential malformation of the lymphatic system.

75-80% of cystic lymphangiomas are seen in the neck and lower face. The most common location in the pediatric population is the posterior cervical space, followed by the oral cavity. In the adult population lymphangiomas are most commonly located in the sublingual, submandibular, and parotid spaces. Less common locations include axilla (20%), mediastinum (5%, as in our case), abdominal viscera (colon, spleen, liver), retroperitoneum (kidneys), scrotum, and skeleton. Of the cystic lymphangiomas located in the mediastinum, the majority are within the anterior or superior mediastinum. Unusual locations include the pericardium, pulmonary hilum, and pulmonary parenchyma. On the other hand, cavernous lymphangioma are commonly located in the tongue, floor of the mouth, or salivary glands. Simple lymphangioma are usually seen in the epidermis or dermis of proximal limbs.

Lymphangiomas are usually asymptomatic and usually discovered in adulthood. However, large cystic hygroma in the neonate and infant may represent a major medical and cosmetic challenge. Some may present with dyspnea or dysphagia due to mass effect on the trachea, pharynx, or esophagus. Other complications include infection, internal hemorrhage, formation of chylothorax/chylopericardium. Suspect infection or hemorrhage when there is sudden enlargement.

Cystic lymphangiomas are commonly associated with chromosomal abnormalities as high as 60-80%; Turner syndrome (45 XO), trisomies (21, 18, 13), Noonan syndrome, etc are commonly seen. Noonan syndrome also called pseudo-Turner, has a phenotype similar to Turner syndrome but with a normal karyotype. Cystic lymphangiomas are also associated with fetal alcohol syndrome. Cystic lymphangiomas in noncervical locations, such as our case, do not carry a significant risk of chromosomal anomalies and usually have a favorable prognosis.

Cystic lymphangiomas have an ultrasound appearance of thin-walled fluid-filled structure with multiple septa of variable thickness and some solid components. Fluid-fluid levels may suggest internal hemorrhage. On CT, poorly circumscribed multiloculated masses of fluid attenuation is seen. On MR, variable signal intensity on T1 depending on the amount of protein in the fluid and usually hyperintense on T2. Again, fluid-fluid levels on MR may suggest hemorrhage.

Surgical excision is the treatment of choice, but recurrence is common due to difficulty in obtaining complete resection. Other treatment such as radiotherapy and injection of sclerosant agents have been proposed, but are still considered controversial.

References

  1. “Thoracic Cystic Lymphangioma (Cystic Hygroma): A Chest Pain Syndrome: A Case Report”. Samantapudi K. Daya, Ramesh M. Gowda, Mamatha R. Gowda and Ijaz A. Khan. Angiology 2004; 55; 561.
  2. “A Case of Axillary Cystic Hygroma”. S. Mansingani, N. Desai, A. Pancholi, A. Parjapati, PA Vohra, S. Raniga. Chest 2005; 15; 517-519.
  3. “Cystic Lymphangioma: Report of Two Atypical Cases”. Erkan Yildirim, Koray Dural, Tevfik Kaplan and Unal Sakinci. Interactive CardioVascular and Thoracic Surgery 2004; 63-65.
  4. Radiology Review Manual. Wolfgang Dahnert. 5th Ed; 2003; 383-385.

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