A 16-year-old female presented with painful progressive swelling and erythematous skin lesions involving the whole of her right lower limb. She had lesions since birth and also had restricted movements but with no other systemic complaints. An examination revealed diffuse swelling of the right lower limb, including the vulva and the lower abdomen. There were multiple erythematous papules, nodules and plaques of varying size that were firm in consistency .
Diffuse swelling of the whole of the right limb with multiple erythematous papules, nodules and plaques
On subjecting the patient for investigations, her bleeding time, clotting time, prothrombin time and complete blood count were normal. Her renal and hepatic parameters were also normal. X-ray  and computed tomography scan revealed soft tissue swelling with diffuse osteolysis of the femur, tibia and fibula. A tentative diagnosis of Gorham's syndrome was made. The other differential diagnosis was Klippel Trenaunay syndrome, but due to the presence of osteoporotic changes in the bone, this was excluded.
X-ray showing diffuse osteolysis of the right lower limb bones compared with the normal left limb
Biopsy of the erythematous nodule showed nodular tumor in the dermis, which was composed of oval- to spindle-shaped epithelioid cells. Multiple vascular spaces containing red blood cells were seen . The nuclei showed a coarse chromatin pattern, and occasional mitotic figures were also noted. The cells were strongly immunoreactive for CD34  and factor VIII-related antigen. Finally, a diagnosis of EHE was made and the patient was referred to the vascular surgery department for further management.
Hematoxylin and eosin showing multiple vascular spaces with red blood cells (×40)