Cutaneous Microthrombosis in a Patient With Factor V Leiden Heterozygosity and Antibodies to Phosphatidylserine/Prothrombin Complex.

This report describes the development of recurrent cutaneous microthrombosis in a patient with the superposition of Factor V Leiden heterozygosity on a noncriteria IgM antibody to phosphatidylserine/prothrombin complex. The patient was treated with prednisone, apixaban, and rituximab and was stable off of prednisone at her last outpatient visit 22 months after the initial event. This report illustrates the challenges of dealing with multifactor thrombophilia especially when one of those factors is a noncriteria antiphospholipid antibody and reaffirms the value of testing for noncriteria antibodies when clinical findings suggest the presence of antiphospholipid antibodies but the criteria antibodies are negative. This report further shows, in this patient, the benefit of the addition of rituximab-pvv to apixaban in normalizing the level of antiphosphatidylserine/prothrombin complex antibodies with the cessation of cutaneous microthrombotic events, normalization of inflammatory markers, and allowing the discontinuation of prednisone. Because of the relatively high frequency of Factor V Leiden heterozygosity in Caucasian populations, this report suggests that dual-factor thromobophilia due to its combination with criteria or noncriteria antiphospholipid antibodies may be more common than is recognized.