Multifocal kaposiform hemangioendothelioma of soft tissue with bilateral pulmonary involvement in an adolescent.

Kaposiform hemangioendothelioma (KHE) is a rare, locally aggressive vascular tumor of intermediate malignancy with resemblance to Kaposi sarcoma. It occurs predominantly in pediatric age groups as a cutaneous lesion with focal infiltration into the adjacent soft tissue and bone. Although visceral involvement is very uncommon, several cases with bone, retroperitoneal, or mediastinal involvement have been described. KHE has been reported to occasionally occur in unusual sites such as the thymus, tonsils, larynx, paranasal sinuses, deltoid muscle, spleen, uterine cervix, thoracic spine, and even the breast. Multifocal KHE is an extremely rare entity with few reports available in the literature, none of which describes pulmonary involvement. Herein, we report a unique case of multifocal KHE in a 13-year-old boy presenting with a huge soft tissue mass in the upper extremity complicated by bilateral pulmonary nodules that developed into large, necrotic tumor masses.