A 41 y.o. woman from China presents with a platelet count of 17,000 and a large lesion in her liver

Could they be related?

Our patient was felt to have Kasabach-Merritt syndrome.  This is a consumption coagulopathy caused by a giant hemangioma of the liver.  This occurs most frequently in infants where the vascular abnormality is caused by a Kaposiform hemangioendothelioma or tufted angioma.  These are rapidly growing malignancies and can be fatal.  Because of this, any thrombocytopenia in infants should prompt a search for a hemangioma.  Simple hemangiomas ( not rapidly spreading) often regress in children and are not part of the syndrome.

this baby was treated with sirolimus and steroids.

Any giant hemangioma in an adult is thought to be able to cause thrombocytopenia by abnormal blood flow causing stasis and platelet trapping. This is similar to the platelet trapping which occurs in the spleen in ITP and in fact,  both conditions are treated with steroids. In Kasabach Merritt syndrome 2/3 of people do not respond to steroids.

Karabach Merritt can be associated with angiosarcoma

In the original syndrome, malignancy was always involved and would require a biopsy to diagnose. Our patient had a ddimer of 2,200 and was treated with steroids.  Her platelet count increased from 17, 000 to 21,000.  Hematology set a goal of 10,000 platelets since transfusion of platelets can make the condition worse.  She will be followed as an outpatient to determine if she needs immunosuppression.  

Mahajan H, Margolin J. Iacobas I. Kasabach Merritt phenomenon: classic presentation and management options. Clin Med Insights Blood Disord. 2017  10:1179545x17699849.

Kasabach H, Merritt K. Capillary hemangioma with extensive purpura: report of a case. Am J dis Child 1940, 59:1063-70.

Rodriguez V, Lee A, Witman P. Kasabach-Merritt phenomenon: case series and retrospective review of experience. J Pediatr Hematol Oncol. 2009; 31:52-526