Kaposiform hemangioendothelioma with Kasabach-Merritt phenomenon in a neonate of life- and limb-threatening nature: A case report.

Kaposiform hemangioendothelioma involving whole of a leg in a neonate with Kasabach-Merritt phenomenon causing limb and life-threatening situation has not been reported. One such case and its successful management is presented in this case report. Literature review is made.

INTRODUCTION

Kaposiform Hemangioendothelioma (KHE) is a rare congenital vascular tumor arising from vascular endothelial cell lining and 60% of it occurs in neonates. Kasabach-Merritt phenomenon (KMP) includes thrombocytopenia, microangiopathic hemolytic anemia and mild consumptive coagulopathy, and occurs in KHE, Kaposiform lymphatic anomaly (KLA) and tufted angioma (TA). KHE with KMP has a high mortality rate of up to 50%.[12] Although complete excision is the treatment of choice, due to its size, site and permeation of multiple tissue planes, KHE can rarely be resected safely. Hence the treatment of KHE with KMP is primarily medical. Treatment options include Corticosteroid,[34] Propranolol,[5] Interferon,[6] Sirolimus,[7] Vincristine,[378] VAT (Vincristine, Aspirin and Ticlopidine),[7] Radiotherapy[1] and Embolization.[5] No treatment is uniformly effective or relapse- and complication-free. Because of the rare nature of the disease, management decisions are based on anecdotal opinion and isolated case reports and series without guidance from prospective trials.[5] The case presented is a KHE with KMP in a neonate of limb- and life-threatening nature due to the involvement of entire leg, ulceration, and recurrent local and systemic sepsis. As drugs such as Prednisolone and Propranolol failed to contain the disease, Vincristine was started and KHE with KMP, ulceration and sepsis resolved, and the limb was saved.

CASE REPORT

One-month-old female baby presented with a circumferential diffuse swelling of entire right leg with reddish purple discoloration noticed since birth, which developed an abscess, ulceration and purulent discharge and sepsis. There was gross edema of right foot and thigh with inguinal adenitis [Figure 1a]. Hematological investigations showed anemia and thrombocytopenia. A diagnosis of KMP was made and a biopsy was carried out after controlling the sepsis, which showed features of KHE. Immunohistochemistry was positive for Vimentin, CD31 and CD34, negative for Cytokeratin and GLUT 1 and Ki67 was 5-10% suggestive of KHE. X-ray of right lower limb did not show any bony involvement or osteomyelitis. MRI showed T2 hyperintense ill-defined circumferential mass involving the entire right leg and lower thigh. Underlying bones and joints were normal [Figure 2]. Doppler correlation of the lesion showed increased vascularity. Arterial feeders were from arteries around the knee joint and the venous drainage was into the tibial vein. The arteries from the external iliac to popliteal artery showed high resistance flow. Distal tibial vessels showed reduced but high resistance flow due to severe external compression. The baby was started on high dose Prednisolone regimen (40 mg orally on alternate days tapered to half the dose every 20 days till a dose of 2.5 mg on alternate days was completed).[9] The KHE and KMP did not show any resolution and Propranolol 2 mg/kg daily orally in two divided doses was added.[5] There was no improvement for five months since admission and the child required frequent hospitalizations for increasing size of the lesion, foul smelling discharge from the fungating ulcer over the lesion, the proximally spreading violaceous discoloration on to the thigh, increasing distal foot edema and life- and limb-threatening systemic and local sepsis. Hence, Vincristine was administered at weekly dose of 0.025 mg/kg[10] for four weeks. The lesion resolved with local wound care and compression stockings gradually over the next 10 months [Figure 1b]. The hematological changes due to KMP also got corrected. Currently, the child is on follow-up.

Figure 1

KHE of right leg before (a) and after (b) Vincristine therapy

Figure 2

MRI of KHE of right leg

DISCUSSION

The prevalence of KHE is 0.91 per 100,000 children. The male: Female incidence is 1.33:1. KHE can be diagnosed in prenatal ultrasound. KHE is classified as superficial when its involvement is restricted to dermis through subcutaneous tissue and deep fascia. KHE is designated as deep when it involves muscle, bone, retroperitoneal or intrathoracic sites, and forms 83% of the cases. KHE is usually unifocal, but multifocal KHE have also been reported. Biopsy proven KHE of liver has never been reported.[2] Seventy-five percentage of cases progressively enlarge during infancy. The superficial component of KHE cause a red-purple discoloration with surrounding ecchymosis.[8]

KMP is hypothesized to be due to abnormal platelet activation and aggregation secondary to interaction with abnormal tumor endothelium resulting in localized trapping of platelets and consumption of clotting factors or due to turbulent blood flow that results from the architecture of the small convoluted capillaries of KHE. Infants with KMP are at risk for intracranial pleural, pulmonary, peritoneal, and gastrointestinal hemorrhage and musculocutaneous pain and decreased function.[2] Thrombocytopenia is unresponsive to platelet transfusion due to intralesional trapping.[8] KMP is less likely to occur in KHE less than 8 cm in size and its incidence increases when KHE is of deep type.[8] The mortality rate of KHE with KMP with life-threatening vasculopathy can go up to 30-50%.[1]

X-ray may show osteolysis due to bony involvement of KHE. MRI of KHE reveals ill-defined, hypo or isointense lesion in T1-weighed images and hyperintense mass with reticular standing in T2-weighed images. Feeding and draining vessels are small relative to tumor size. Doppler studies correlate these vascular changes of the lesion.[8] Histopathology of KHE reveals aggressive infiltration of normal tissues by sheets or lobules of oval or spindle endothelial cells, dilated lymphatic channels and slit-like vascular spaces filled with hemosiderin and compacted erythrocytes suggesting stasis.[8] There is characteristic absence of mitosis or nuclear atypia. There is focal immunopositivity for lymphatic endothelial markers.[2] The children with KHE with KMP who showed resolution require a close follow-up, as KMP can recur latter.[1] Authors believe that publication of number cases of this rare lesion may help to evolve a uniform treatment policy.