Lymphangioma Circumscriptum Secondary to Cystic Hygroma

Dear Editor, A four-year-old female presented with recurrent, painless unilateral abdominal and thoracic swelling, accompanied by crusted vesicles that evolved into thick, hyperkeratotic plaques with a verrucous appearance [Figures 1 and 2]. Notably, areas around a prior surgical scar were spared, while other regions without previous surgery were affected. At birth, the patient had lateral abdominal swelling extending to the neck, associated with a localised eruption of erythematous vesicles, for which she underwent surgical excision at 10 days of age. She remained stable until 1.5 years of age, when progressive swelling in the thoracic region led to abdominal distension, respiratory distress, and poor oral intake.Figure 1: Thoracic and abdominal cystic hygroma with lymphangioma circumscriptum presenting as overlying grouped vesiclesFigure 2: Infrascapular cystic hygroma with overlying lymphangioma circumscriptum presenting as hyperkeratotic plaques with a verrucous appearanceHistopathological examination of a subsequent excision revealed thickened cyst walls, granulation tissue, chronic inflammation, necrosis, and lymphoid cell aggregation. Cystic spaces lined by endothelial cells confirmed the diagnosis of lymphangioma circumscriptum (LC) [Figure 3]. Ultrasonography demonstrated multicystic, echogenic lesions with small anechoic cysts in the deep subcutaneous tissue of the left lateral chest wall, extending to the heart, left subdiaphragmatic region, epigastric area, and posteriorly to the infrascapular region. Larger cysts were noted in the left upper chest wall and infrascapular area. Imaging also revealed rib splaying and scoliosis of the upper dorsal spine, suggesting osseous involvement. These findings were consistent with cystic hygroma, with extensive thoracic and abdominal involvement.Figure 3: (a) Histopathology of the excised tissue showing thickened cyst walls, granulation tissue, chronic inflammation, necrosis (green arrow), lymphoid aggregation (red arrow), and dilated lymphatic channels (blue arrow), consistent with lymphangioma [Hematoxylin and eosin, 10×]; (b) histopathology of the excised tissue showing dilated cysts lined by endothelium (yellow arrow) and lymphoid infiltrate (red arrow) [Hematoxylin and eosin, 40×]The patient was scheduled for cryotherapy to address superficial LC and referred for pediatric surgical evaluation for potential excision of the cystic hygroma. However, the patient declined further management due to previous recurrence of the condition and financial constraints; thus, the planned intervention was not pursued. Cystic hygroma is a benign congenital lymphatic malformation characterized by cystic structures extending into surrounding tissues, lined with endothelial cells and filled with lymphatic fluid. It results from the sequestration of lymphatic tissue during embryogenesis, which fails to integrate with the developing lymphatic or venous systems, causing cystic dilation.[1] It is identified in up to 90% of cases by age two, most commonly presenting in the posterior neck (75%) and axilla (20%), with rare occurrences in the mediastinum, retroperitoneum, and scrotum. Complications include hemorrhage, infections, abscess formation, airway obstruction, dysphagia, and obstructive sleep apnea.[2] In rare cases, cystic hygroma may lead to cutaneous complications like LC. LC, a microcystic lymphatic malformation, presents as hamartomatous skin lesions with small, translucent vesicles containing lymphatic fluid, which may become discoloured due to hemorrhage. These lesions can rupture, form crusts, bleed, and develop into thick, verrucous plaques and localised swelling. Acquired LC typically occurs later in life due to trauma, surgery, radiotherapy, or infections affecting deep lymphatics. While LC is rarely associated with systemic diseases or malignant transformation, it can arise secondary to cystic hygroma, as seen in a nine-year-old girl who developed LC, seven years postsurgical removal of a cystic hygroma.[3] Both cystic hygroma and LC stem from disruptions in lymphangiogenesis during embryogenesis, a process regulated by vascular endothelial growth factor C (VEGF-C) and vascular endothelial growth factor 3 (VEGF-3). While these conditions share a common molecular basis, their clinical presentations, anatomical distribution, and the extent of malformations suggest distinct developmental pathways for each.[4] There is no consensus on the optimal treatment for the superficial lymphatic component of vascular malformations, as current options commonly employed like surgical excision, are often associated with high recurrence rates and significant side effects. However, other approaches, including sclerotherapy, cryotherapy, and CO2 laser therapy, have been employed, but their efficacy is often limited due to the complex nature of the condition. Addressing the underlying cystic hygroma may also help alleviate symptoms and promote regression of the lymphangioma. Rapamycin, an mammalian target of rapamycin (mTOR) inhibitor, has shown promise in treating lymphatic malformations, especially microcystic forms. Studies have reported favourable results, including volume reduction and pain relief with minimal side effects, particularly when applied topically. Sirolimus, a form of rapamycin, has demonstrated a 90% response rate in children with head and neck lymphatic malformations, leading to improvements in volume, pain, and skin changes.[5] This effect is believed to result from the inhibition of VEGF and mTOR pathways, both crucial in lymphangiogenesis. However, further studies are needed to fully confirm its efficacy and underlying mechanisms. In conclusion, while surgical excision remains the standard treatment for LC, alternative therapies such as rapamycin offer promising, less invasive options. The connection between cystic hygroma and LC emphasises the need for careful monitoring and individualised treatment approaches. Further research into molecular therapies may offer new hope for managing these challenging lymphatic malformations. Declaration of patient consent The authors certify that they have obtained all appropriate parent consent forms. In the form a parent has given their consent for her images and other clinical information to be reported in the journal. The parent understands that her name and initials will not be published and due efforts will be made to conceal her identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest. Use of artificial intelligence (AI) The preparation of this manuscript was carried out entirely by the authors without the use of artificial intelligence technologies.