3.1 | Case 1: KHE with KMP
Patient 1 presented at 3 months of age with petechiae and purpura on his extremities. He had been diagnosed with an upper respiratory infection and placed on a 10-day course of antibiotics within the previous 2 weeks from presentation. Upon presentation to the emergency department his platelet count was 2,000/mm3. Given his presentation and recent viral illness, he was initially diagnosed with idiopathic thrombocytopenia (ITP) and was given intravenous immunoglobulin (IVIG) 1g/kg. The following day his platelets remained at 11,000/mm3 and hemoglobin declined to 8.7 g/dL. [Figure 1]
Ultrasound of the abdomen was performed as there was concern for splenomegaly and due to the atypical ITP presentation at this age. A retroperitoneal mass was discovered that appeared to be coming from the tail of the pancreas. Computed tomography (CT) was performed for better visualization and confirmed a 6.2 cm x 3 cm mass with heterogeneous attenuation encompassing the splenic artery and extending into celiac axis. Patient went to the operative room for biopsy of the lesion. Prior to the procedure he was transfused platelets and platelet count increased to 55,000/mm3. He had no bleeding complications with the procedure. Coagulation panel was obtained on hospital day 2 and revealed fibrinogen of 163 mg/dL and elevated d-dimer of 22. This was repeated on hospital day 6 and fibrinogen was 299 mg/dL and d-dimer 21.7.
Pathology was consistent with KHE. Given the thrombocytopenia and elevated D-dimer he was diagnosed with KMP and prednisone 2mg/kg/day was initiated. Consent was obtained from the family and he was started on weekly intravenous vincristine 0.05mg/kg. His fibrinogen initially dropped to 90 mg/dL and he was given cryoprecipitate, but his platelets began to improve after only a couple of days of corticosteroids. Over the subsequent 4 weeks his fibrinogen fluctuated from 86 mg/dL to 178 mg/dL and his platelets from 37,000/mm3 to 206,000/mm3. Steroids were very slowly weaned and were discontinued once fibrinogen and platelets had consistently normalized. The lesion was imaged with magnetic resonance imaging (MRI) every 3 months and saw initial shrinkage but then remained stable. He was treated with 3 12-week cycles of vincristine and at the end of therapy, his blood counts were normal and the KHE lesion was stable at 1.4 cm x 4 cm. He is now 5 ½ years off therapy and doing well with no recurrent of the KMP and no evidence of progression of the tumor.