Cystic hygroma modified by a multitude of minute overlying swellings: Expanding the clinical spectrum

Dear Sir,

A 2-month-old male infant, born through an uncomplicated full-term normal vaginal delivery, presented to the dermatology department with a progressively enlarging neck mass noted since birth. The parents denied any associated respiratory distress or feeding difficulties. No abnormalities were detected in his prenatal second-trimester anomaly scan.

On physical examination, a solitary, soft, non-tender cystic swelling measuring approximately 12 × 8 cm was observed over the right side of the neck [Figure 1a]. The overlying skin exhibited multiple small, coalescing cystic papules and plaques. Transillumination of the lesion was negative. No lymphadenopathy or developmental delay was noticed. Ultrasonography revealed an anechoic cystic mass with internal floating septations and a floating solid component. Contrast-enhanced magnetic resonance imaging (MRI) demonstrated a large, lobulated, exophytic, multicompartmental cystic lesion with internal fat content and extension into the mediastinum and axilla, consistent with lymphangioma [Figure 1b]. Histopathological examination was taken from the overlying papular swelling that showed multiple variably sized, dilated lymphatic spaces lined by round to oval endothelial cells [Figure 2a]. Immunohistochemistry was positive for D2-40 and CD31, confirming the diagnosis of cystic hygroma [Figure 2b]. His laboratory workup showed increased alpha-fetoprotein and lactate dehydrogenase levels.

Close

Figure 1:

(a) Multiple small, coalescing cystic papules and plaques containing whitish fluid overlying the cystic hygroma. (b) An ill-defined, large, lobulated cystic multi-compartmental hyperintense mass on T2-weighted magnetic resonance imaging, located in the posterior triangle of the neck, involving the subcutaneous plane.

Export to PPT

Close

Figure 2:

(a) Multiple variably sized, dilated lymphatic spaces lined by round to oval endothelial cells (Hematoxylin and Eosin, ×40). (b) Immunohistochemistry staining of endothelial cells with D2-40.

Export to PPT

The patient underwent surgical excision by the pediatric surgery team. Postoperatively, persistent chylous drainage was noted. Subsequently, the infant developed septic shock and respiratory distress, necessitating transfer to the pediatric intensive care unit. Despite supportive management, his condition deteriorated, and the patient succumbed to his illness.

Cystic hygromas are lymphatic malformations first described by Wernher. They result from developmental anomalies in the lymphatic system, with the most widely accepted pathogenetic theories being either sequestration or abnormal budding of primitive jugular lymph sacs.^[1] These lesions can be congenital or acquired and are clinically significant due to their size and infiltrative nature, often compromising respiration, swallowing, or nerve function. About 55% of cystic hygromas are associated with chromosomal aneuploidies and genetic syndromes, including Turner syndrome (21%), Trisomy 21 (17%), Trisomy 18 (10%), Trisomy 13 (3%), Noonan syndrome, and other congenital disorders.^[2] Late-onset cystic hygroma occurs after 30 weeks of gestation or postnatally and typically presents as a localized cystic lymphatic lesion without other anomalies.^[3]

They are most commonly located in the cervicofacial region, axilla, and mediastinum, but may also involve visceral organs such as the liver, spleen, kidneys, and intestines. Clinically, cystic hygromas present as soft, smooth, compressible, non-tender, and transilluminant masses containing serous, milky, serosanguinous, or straw-colored fluid. Ultrasonography typically reveals a multicystic lesion with internal septations, aiding in prenatal diagnosis. MRI and computed tomography imaging offer better delineation of lesion extent. Histopathologically, they are composed of multiple cystic spaces lined by flattened endothelial cells and separated by connective tissue stroma, often containing lymphoid aggregates. The differential diagnosis in the neck may include branchial cleft cyst, hemangioma, thyroglossal duct cyst, dermoid cyst, thymic cyst, laryngocele, thyroid mass, and lipoma.^[4]

Management of cystic hygroma depends on the time of its diagnosis. In cases with prenatal diagnosis, factors such as septate cystic hygroma, increased nuchal translucency, elevated maternal serum alpha-fetoprotein, and early gestational detection are associated with poor prognosis.^[5] Spontaneous resolution before 20 weeks of gestation is considered a good prognostic factor, seen in about 20% cases.^[2] Those cases with persistent lymphangioma after 20 weeks, structural abnormalities, and abnormal karyotyping should be advised to undergo termination of pregnancy.^[5] In postnatal cases, surgical excision remains the cornerstone of treatment for complete removal. The success of surgery depends on the lesion’s location, with those confined to the posterior triangle of the neck generally having the most favorable outcomes. In contrast, complex multicystic lesions extending into the mediastinum or mucosal areas are more challenging, with recurrence rates reaching up to 20%. Alternative therapeutic modalities, including sclerotherapy, aspiration, sclerosing agent, laser excision, radiofrequency ablation, and cauterization, should be employed based on lesion characteristics and patient factors.^[6]

Our case features multiple cystic swellings overlying a cystic hygroma, highlighting a rare and atypical presentation of secondary cutaneous lymphatic changes. The late-onset nature of the lesion, which was associated with a poor outcome, highlights the importance of regular ultrasonographic monitoring during the third trimester.