Presentation
Born via spontaneous vaginal delivery with extensive left lower limb swelling since birth. Lab tests revealed thrombocytopenia with a platelet count of 68,000. D-dimer elevated at 3,250 mcg/L.
Patient Data
Lateral radiograph shows increased soft tissue density and bulk in keeping with extensive limb overgrowth.
MRI of the left lower limb shows extensive unilateral limb overgrowth with ill-defined thickening involving multiple tissue planes. There is thickening and hyperenhancement of the skin with marked enlargement and reticular stranding of the subcutis. Abnormal signal and thickening are also noted in the anterior thigh musculature. Large dilated veins are seen in the calf.
Case Discussion
Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor, typically presenting in infancy as a distinctive cutaneous lesion with ill-defined borders. KHE can be confused with infantile hemangioma due to the age of presentation and presence of a vascular cutaneous lesion.
KHE tends to proliferate over several months followed by slow involution over many years.
KHE is an infiltrative tumor that has a tendency to cross tissue planes involving dermis, subcutis, fascia, muscle and bone.
T1 weighted imaging reveals characteristic, ill-defined hypointense soft tissue thickening involving multiple planes. T2 typically demonstrates hyperintense masses with reticular stranding in the subcutaneous fat.
Kasabach-Merritt phenomenon (KMP) is profound thrombocytopenia which results from intralesional platelet trapping. KMP occurs with KHE and tufted angioma but not infantile or congenital hemangioma.