Successful management of steroid-resistant vascular tumors associated with the Kasabach-Merritt phenomenon using sirolimus

Abstract

Vascular tumors associated with Kasabach-Merritt phenomenon (KMP) are life-threatening and the mortality is as high as 10-30%. Steroids are considered the primary choice for drug therapy. However, there are many steroid-resistant cases. In the present study, analyzed data are presented to support the use of sirolimus in clinical practise for the treatment of corticosteroid-resistant vascular tumors with KMP in eight infants between June 2015 and April 2017 in a single hospital. The time to initial response was 6.8 ± 2.7 days. The average stabilization time for the platelet count was 19.1 ± 8.5 days. At the time of publication, the average duration of sirolimus treatment was 14.1 ± 4.0 months, and the average time for sirolimus treatment as a single agent was 12.6 ± 4.2 months. The side-effects were tolerable and included oral ulcer, fever, pain, skin rash and transient ascension of serum transaminase and cholesterol. Our study indicated that sirolimus therapy is an effective and safe method for the treatment of corticosteroid resistant vascular tumors associated with KMP in infants.

Keywords: Kasabach-Merritt phenomenon; hemangioendothelioma; mammalian target of rapamycin inhibitor; sirolimus; tufted angioma.

Figure 1

A patient aged 18 months with Kasabach–Merritt phenomenon in the maxillofacial region, neck and anterior chest wall. (a–b) Magnetic resonance imaging (MRI) examination showed extensive lesions in the right and left maxillofacial region, neck and anterior chest wall with unclear boundaries, a high signal intensity on enhanced T₁‐weighted images and tracheal compression. The patient had undergone four transcatheter arterial embolizations, more than 2 years of steroid use and intermittent vincristine therapy before sirolimus treatment. However, the condition was recurrent, and the platelet level continued to decline. (c–d) MRI re‐examination after 10 months of sirolimus therapy revealed that the lesions had disappeared from the maxillofacial region, neck and anterior chest wall.