Lymphatic Malformation (Cystic Hygroma) Workup

Updated: Dec 14, 2020
  • Author: Vijay A Patel, MD; Chief Editor: Ravindhra G Elluru, MD, PhD  more...
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Workup

Laboratory Studies

Studies have suggested that fluorescent in-situ hybridization (FISH) can be used to evaluate for lymphatic malformation (LM) in antenatal chromosomal analysis (chromosomes 13, 18, 21, X, and Y). [11]

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Imaging Studies

Magnetic resonance imaging (MRI), computed tomography (CT), and ultrasonography (US) are all helpful in delineating the nature of a cystic neck mass. CT and MRI reveal a ringlike margin enhancement with sharp demarcation of cystic areas. The cystic areas tend to appear circumscribed and discrete. A poorly defined isodense mass that obscures muscle and fatty planes is more consistent with a microcystic LM.

Magnetic resonance imaging

MRI is the consensus study of choice. It provides the best soft-tissue detail and can delineate the relation of the lesion to surrounding structures. Contrast can be used to differentiate hemangiomas from lymphangiomas. On MRI, LMs appear hyperintense on T2-weighted images and hypointense on T1-weighted images.

Computed tomography

CT is faster than MRI and may be more readily available; however, it carries the risk of radiation exposure, and detail is lost if the LM is surrounded by tissues of similar attenuation. Contrast helps to enhance cyst-wall visualization and the relation to surrounding blood vessels. On CT, LMs appear isodense to cerebrospinal fluid (CSF). (See the image below.)

Saggital CT reveals a large lymphatic malformation Saggital CT reveals a large lymphatic malformation which required intubation due to respiratory distress

Ultrasonography

US is the least invasive study. It is very useful in demonstrating the relationship of LM to the surrounding structures; however, it is of limited value for assessing mediastinal and retropharyngeal structures. US can also be used to detect LM in utero. Echographic visualization of multiple septa in fetal LM has been postulated to be a poor prognostic indicator. [8]

Plain radiography

With any large mass of the head and neck, airway radiography (high-kilovolt anteroposterior and lateral neck radiographs or airway fluoroscopy) can be helpful in delineating possible airway compromise. Plain radiography is a reasonable initial imaging modality in the evaluation of a neck mass with potential airway manifestations.

Lymphoscintigraphy

A case report has also highlighted the ability to visualize LM by means of lymphoscintigraphy. [12]

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Histologic Findings

LMs are composed of large irregular sinuses with a single layer of flattened epithelial lining and fibrous adventitial coats. The thickness of the vessel wall varies, with both striated and smooth muscle components. 

Although most LMs are multicystic, a unilocular cyst is found in approximately 10% of cases. Cysts can range from 1 mm to several centimeters in size and are filled with clear- to straw-colored fluid, which is eosinophilic and protein-rich. Individual cysts may be isolated or may freely communicate. The surrounding stroma is fibrous or fatty and may contain lymphoid aggregates, smooth muscle, or other local tissues.

LMs may contain multiple subtypes (eg, capillary and cavernous) and, in these instances, are categorized according to the predominant subtype. In addition, lesions with a hemangiomatous component are considered hemangiolymphangiomas. Hemorrhage into the cyst is common and can be secondary to trauma or spontaneous bleeding.

Capillary LMs contain capillary-sized lymphatic channels that involve the epidermis. Cavernous LMs infiltrate surrounding structures and are dilated lymphatic channels. Macrocystic LMs are cystic masses lined by a single layer of endothelium with a connective-tissue stroma.

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Staging

Classification has been marred by a historical lack of conformity. In 1877, the first system was proposed by Wegener. In 1982, Mulliken and Glowacki presented a cell-based classification of pediatric vascular lesions that is currently used by many authors. [13] Their system stratified lesions into two types: hemangiomas and vascular malformations, with LMs falling into the latter category. The World Health Organization (WHO) recognizes three types of lymphangiomas: capillary, cavernous, and cystic. The former is a synonym for microcystic lymphangioma, and the latter two are macrocystic lymphangiomas. A cystic hygroma is a macrocystic lymphangioma found in the neck.

Giguère et al proposed categorizing lymphangiomas on the basis of the size of the cystic component  [14] :

  • Macrocystic - Cystic spaces ≥2 cm
  • Microcystic - Cystic spaces < 2 cm
  • Mixed lesions

De Serres et al proposed the following system for staging of LMs of the head and neck  [15] :

  • Stage I - Unilateral infrahyoid (17% complication rate)
  • Stage II - Unilateral suprahyoid (41% complication rate)
  • Stage III - Unilateral and both infrahyoid and suprahyoid (67% complication rate)
  • Stage IV - Bilateral suprahyoid (80% complication rate)
  • Stage V - Bilateral infrahyoid and suprahyoid (100% complication rate)
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