Kaposiform lymphangiomatosis (KLA) is a rare lymphatic anomaly associated with a poor prognosis. Disease hallmarks include multifocal, intra- and extra-thoracic lymphatic malformations, thrombocytopenia and consumptive coagulopathy.
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Epidemiology
The exact prevalence and incidence of kaposiform lymphangiomatosis is unknown, but the disease is very rare. The disease usually presents at birth or early childhood; however, reports exist of disease manifestations later in life 1. Males and females appear equally affected. The exact cause is unknown; however, genetic factors and changes in utero are thought to contribute to disease development.
Clinical presentation
Due to the generalized and multi-system involvement of the disease, clinical presentation can vary, making diagnosis difficult. The most common presenting features include:
respiratory symptoms (dyspnea, cough)
bleeding/hemorrhage - often secondary to coagulopathy
pericardial and pleural effusions (often hemorrhagic)
fractures secondary to bone involvement
discrete tissue swelling/mass
The disease often involves both intra- and extrathoracic structures of the chest and abdomen.
Pathology
Kaposiform lymphangiomatosis arises due to a malformation of the lymphatic system. It is characterized by multi-organ involvement and nearly all patients have intrathoracic involvement. The organs most commonly involved are the lungs, the heart, bones, and the spleen.
Microscopic appearance
Histopathology generally shows malformed dilated lymphatic channels associated with clusters or sheets of spindle-like cells. There is no atypia or dysplasia. Immunochemical staining is positive for markers of lymphatic endothelium.
Radiographic features
Imaging varies depending organ systems affected but is useful to aid in diagnosis.
Plain radiograph
Plain radiographs are of limited use as they often show nonspecific changes but may demonstrate changes in keeping with lung disease on chest radiographs (e.g. pleural effusions). Plain radiographs may also be useful in bone imaging, showing lytic lesions with cortical sparing, asymmetrically involving the axial and/or appendicular skeleton 4.
CT
CT imaging of the chest may demonstrate:
infiltrative, enhancing soft tissue thickening along bronchovascular bundles (following lymphatic distribution)
masses of low attenuation 4
CT imaging of the abdomen may demonstrate:
organomegaly, especially splenomegaly, hepatomegaly or nephromegaly
hypodense cystic lesions involving the spleen, kidneys, and pancreas
retroperitoneal involvement is common and may demonstrate an enhancing, infiltrative soft tissue mass, commonly with extension to other structures, including the mesentery, hepatic or renal hila, or along vessels in these regions 4
MRI
MRI imaging of the chest may demonstrate:
mass or soft tissue thickening as on CT that is heterogeneous and hyperintense on fluid-weighted sequences, with moderate to intense post-contrast enhancement 4
MRI imaging of the abdomen may demonstrate:
cystic lesions that are heterogeneous and hyperintense on fluid-weighted sequences 4
Treatment and prognosis
There is no current consensus on treatment, but patients are treated with a combination of medical and surgical therapies. Medical therapies may include combinations of steroids, chemotherapy and immunomodulators (interferon, sirolimus, vincristine) but responses are unpredictable. Surgical procedures are usually for symptomatic benefit; however, splenectomy appears beneficial in some patients for refractory thrombocytopenia.
Prognosis is generally poor, as the disease is progressive despite medical intervention.