CHEST

Lymphatic malformations (LMs) are more common in the thorax than venous malformations (VMs) or arteriovenous malformations (AVMs). Extracutaneous chest LMs are typically located in the mediastinum or retropleural area and may be in continuity with the neck, thoracic inlet, retroperitoneum, or soft tissue lesions. Mediastinal LMs are usually asymptomatic; small-to-moderate-sized lesions may be observed. Large LMs can cause airway compression or pulmonary compromise and require treatment. Macrocystic LMs are amendable to image-guided sclerotherapy. However, symptomatic microcystic lesions may need resection. Lymphatic anomalies of the chest can result in pleural effusion. Medical management for a chylothorax can be attempted (for example, a fat-restricted diet, octreotide, or sirolimus). Small effusions or those causing tolerable symptoms can be treated nonoperatively. Interventions (for example, pleurodesis, lymphovenous anastomosis, or thoracic duct ligation) are performed if symptoms continue despite medical therapy. LMs of the lung parenchyma are uncommon. Congenital pulmonary lymphangiectasia is a rare anomaly that is characterized by severe respiratory distress of the newborn; the prognosis is poor. Supportive treatment with ventilation and extracorporeal membrane oxygenation may be indicated. VMs and AVMs rarely occur in the chest cavity. Symptomatic lesions typically are managed with endovascular interventions rather than resection.

ABDOMEN

Although hemangiomas are the most common vascular anomaly, hemangiomas of the chest cavity and abdomen are typically clinically silent because of their predictable pattern of involution. The liver is the most frequent extracutaneous site of these tumors. The presence of five or more skin hemangiomas (hemangiomatosis) may be indicative of a liver lesion. Hepatic hemangiomas are categorized into (1) focal, (2) multifocal, or (3) diffuse. Focal hepatic hemangiomas are rapidly involuting congenital hemangiomas (RICH), which undergo more than 90% volume reduction by 13 months of age. A small subcapsular hepatic nodule remains after involution, and therapy is rarely required. Multifocal hepatic hemangiomas are infantile hemangiomas that have a growth pattern similar to skin lesions. Most patients are asymptomatic, but a subset develops: (1) consumptive hypothyroidism because of the expression of a deiodinase by a hemangioma, which inactivates the thyroid hormone, and/or (2) high-output cardiac failure from shunting. Diffuse hepatic hemangiomas replace an extensive portion of liver parenchyma. Patients may be diagnosed within several months of birth because of massive hepatomegaly, respiratory compromise, abdominal compartment syndrome, or heart failure. Hypothyroidism is treated with aggressive thyroid hormone supplementation. Thyroid function normalizes with tumor involution. Children exhibiting heart failure can be managed with pharmacotherapy (steroids or propranolol). Endovascular embolization is rarely used for cardiac failure. Patients with diffuse hepatic hemangiomas who have abdominal compartment syndrome and show clinical deterioration may require liver transplantation.

Abdominal LMs that leak into the peritoneum can form chylous or nonchylous (clear) ascites. Chylous leaks occur from the lymphatics of bowels, mesentery, or retroperitoneum that contain lipids. LMs causing persistent ascites may require exploratory laparotomy, localization of the origin of the leak, and removal of the inciting area.

VMs of the abdomen can be focal, multifocal (for example, blue rubber bleb nevus syndrome [BRBNS]), or diffuse. These lesions may result in gastrointestinal or intraperitoneal hemorrhage. Symptomatic focal lesions can be treated with endoscopic sclerotherapy or segmental bowel resection. Patients with multifocal VMs who require chronic blood transfusions may undergo surgical eradication of all the luminal lesions with intraoperative endoscopic assistance. Nonsurgical management (pharmacologic therapy or endoscopic treatment) for BRBNS has not been durably effective; however, early experience shows some optimism for sirolimus in this regard. In contrast, diffuse VMs are treated with selective excision of the symptomatic area. These lesions typically encompass the left colon to the anus and are managed with left colectomy, mucosal proctectomy, and coloanal pull-through. In some patients repeated sclerotherapy of the submucosal anorectal VM may avoid or delay the need for pull-through.

Hepatic VMs are common and frequently mislabeled “hemangiomas” or “cavernous hemangiomas.” These lesions are typically asymptomatic until adulthood. They can cause pain during pregnancy and rarely may rupture. Intralesional sclerotherapy is preferred if treatment is required, although surgical extirpation is also used. Rare abdominal “AVMs” are usually VMs that are incorrectly classified. True intestinal AVMs may be amendable to segmental intestinal resection.

GENITALIA

Vascular malformations of the genitalia can cause psychosocial morbidity and defecatory, urinary, and/or sexual dysfunction. The lesions are concealed by clothing and often lower self-esteem. LMs of the scrotum can masquerade as inguinal hernias; an ultrasound examination may help with diagnosis and prevent an inguinal exploration for suspected hernia. Compression garments are recommended for slow-flow vascular malformations. Interventions for lesions that are not causing functional symptoms are often delayed until anatomic maturity, although extreme deformity can be addressed earlier. Genital LMs are rarely macrocystic. Resection is preferable to sclerotherapy for symptomatic slow-flow malformations of the male genitals; surgical scrotal scars are well hidden, and fluoroscopic testicular exposure is prevented. Bleeding endourethral VMs should be treated with laser photocoagulation. AVMs are rare and usually managed with embolization and debulking.

Genital lymphedema affects both genders. Conservative treatment involves prevention of infection and compression. Surgical intervention is reserved for patients with significant morbidity into puberty despite nonsurgical management. Resections for female genital lymphedema are generally not performed. Excisional procedures are used for penile and scrotal lesions.

SURGICAL MANAGEMENT

CHEST

Large vascular malformations of the thorax can cause airway compression or respiratory compromise from mass effect. In contrast to macrocysts, microcystic LMs are not amendable to sclerotherapy and necessitate resection if they are symptomatic. These lesions typically involve the mediastinum and retropleural and retrocrural spaces. Surgery is avoided before age 6 months unless there is an immediate airway threat. At this age, the risk of anesthesia is diminished, and the infant is less susceptible to airway complications from postoperative edema. Vascular malformations do not require total extirpation, because they are not malignant. However, extensive removal of the lesion should be performed while preserving vital structures. Remnant LMs can reexpand, and reoperation is more challenging. Large, anterior mediastinal microcystic LMs may be debulked with median sternotomy. These lesions can involve the airway, esophagus, nerves, thymus, and vascular structures. The phrenic, recurrent laryngeal, and vagus nerves should be preserved. Posterior mediastinal and apical lesions are better exposed with a thoracotomy.

A lymphatic anomaly may leak and cause a pleural effusion. The chylothorax does not usually resolve with excision of the lesion. Chemical (for example, bleomycin, doxycycline, or talc) or mechanical pleurodesis with stripping or abrasion of the parietal pleura can be used for treatment. Pleurodesis creates inflammation to facilitate adherence of the visceral and parietal pleura. However, it is difficult to maintain pleural apposition with high-volume lymph leakage from malformations, and these techniques are less successful than pleurodesis for other causes of effusion. Microvascular lymphovenous anastomosis of the thoracic duct has also been successful. The thoracic duct can be ligated near the diaphragm to decrease chylothorax if other treatments have failed. The duct can be localized during thoracoscopy or thoracotomy by enteral fat loading (for example, a bolus of heavy cooking cream through a nasoduodenal tube).

ABDOMEN

LMs causing persistent ascites are difficult to manage, because localization of the leaking area is challenging. Nonchylous ascites from an LM of a solid organ (for example, the kidney) may have an atypical appearance on imaging and obvious swelling on laparotomy; nephrectomy may be required. It can be more problematic to find the cause of abdominal chylous ascites, because the bowel, mesentery, or retroperitoneal sources have chyle-filled lymphatics that are difficult to identify.

VMs of gastrointestinal hollow viscera may cause bleeding. The surgical approach is dependent on whether the lesion is (1) localized, (2) multifocal, or (3) diffuse. A segmental bowel resection can be performed for a symptomatic, focal VM localized to a limited region of bowel. Multifocal VMs occur in BRBNS. Patients with this condition have multiple VMs distributed throughout the viscera and eventually have gastrointestinal hemorrhage and anemia. An aggressive resection is indicated to eradicate all the VMs from the bowel lumen to resolve the bleeding. Laparotomy is performed with total intraoperative endoscopy from mouth to anus. Segmental bowel resection is limited to areas with many adjacent lesions. Enterotomies are created to access and remove mucosal VMs that are sparsely distributed by intussuscepting and inverting adjacent bowel segments. The mean operative time is 14 hours, and more than 130 lesions are typically removed.

Diffuse abdominal VMs may involve large segments of bowel, mesentery, and the retroperitoneum. In contrast to the multifocal VMs found in BRBNS, eradication of all lesions is not possible. Only the areas of hemorrhage must be removed. Diffuse gastrointestinal VMs usually cause chronic hematochezia. Diffuse colorectal VMs typically surround the rectum. Full-thickness resection of the rectum may result in uncontrollable bleeding. These lesions can be treated with anorectal mucosectomy, partial colectomy, and coloanal pull-through. The left colon is resected down to the peritoneal reflection, and the mucosa of the remaining rectum is stripped from the muscular rectal wall similar to the management of ulcerative colitis or familial polyposis. Endoanal sensation is maintained by preservation of the rectal mucosa for about 1 cm above the dentate line.

GENITALIA

Resection is indicated for symptomatic vascular malformations of the male genitalia. Sclerotherapy or excision can be performed for a focal VM of the glans penis. VMs of the penile shaft are typically superficial to the Buck fascia. These lesions can be excised, with preservation of the deep dorsal nerves and vessels and closed linearly. LMs of the penis are also located superficially in the subcutaneous tissues. Penile lesions are resected through a circumferential incision proximal to the corona of the glans penis. The shaft skin is degloved circumferentially to the base. The diseased tissue is removed off the Buck fascia, and the shaft integument is redraped. Excess circumference of the skin is trimmed to leave a longitudinal scar at the ventral midline. Penile lymphedema is removed with a similar technique.