Multifocal lymphangioendotheliomatosis with thrombocytopenia: phenotypic variability and response to rapamycin.

Introduction: Multifocal lymphangioendotheliomatosis with thrombocytopenia (MLT) is characterized by multiple maculopapular lesions involving the stomach and the lungs, associated with thrombocytopenia as a result of platelet entrapment. Episodes of severe digestive bleeding, which are sometimes unmanageable, are one of its most frequent presentations and a cause of mortality. Our objective was to describe the various phenotypes, as well as our treatment experience.

Materials And Methods: A retrospective analysis of patients diagnosed with MLT in our vascular abnormality unit from 2007 to 2018 was carried out. Epidemiological, clinical, and evolution data were analyzed, and a long-term follow-up was performed.

Results: Five patients (3 boys and 2 girls) had congenital macules and erythematous papules of various sizes. They were later associated with episodes of severe hematemesis along with thrombocytopenia, which required blood product transfusion. The most frequently involved areas were the stomach and the colon. In two patients, multiple bilateral pulmonary nodules were noted. The anatomical pathology examination showed extended vessels with a prominent, hobnail endothelium, as well as intraluminal papillary projections in the dermis. Immunohistochemical analysis was CD-31 positive and CD-34 positive in a characteristic manner. Two patients were treated with mTOR inhibitors (rapamycin), with a progressive decrease in extracutaneous involvement and platelet recovery, but with a poor response in dermal lesions. Two patients were treated with vincristine, with a reduction of digestive bleeding episodes. No deaths were reported in our series.

Conclusion: MLT is characterized by hematological and cutaneous involvement - sometimes minimal -, with potential lesions in other internal organs. Its heterogeneous presentation, which may start with severe digestive bleeding, makes this rare pathology difficult to diagnose. mTOR inhibitors have opened up new treatment possibilities.