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.

Intraabdominal LMs may involve the mesentery, omentum, or retroperitoneum. Large lesions may be symptomatic (for example, diarrhea, distention, nausea, or pain). Most LMs are macro-cystic and are best managed with image-guided percutaneous sclerotherapy. Microcystic LMs less commonly occur in the abdomen and are usually asymptomatic. Surgical extirpation may be indicated for large, microcystic lesions causing mass effect.

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.