A Case Report of Systemic Capillary Leak Syndrome: When More Than One Inciting Factor Exists, the Question Is Who Pulls the Trigger?

Systemic capillary leak syndrome (SCLS) constitutes a rare clinical entity. It is characterized by spontaneous, recurrent episodes of increased capillary permeability, leading to a double clinico-biological paradox: diffuse pitting edema with hypovolemia or hypovolemic shock, and hemoconcentration with hypoalbuminemia, in the absence of secondary causes for such abnormalities. Even though several theories have been proposed, the exact pathophysiology of SCLS remains unclear. We report herein a case of idiopathic SCLS in a 38-year-old male patient with a history of previous immunization, following COVID-19 infection, who was also diagnosed with a myeloproliferative neoplasm (MPN). To our knowledge, this is the first case where SCLS coexists with an MPN, leading to a legitimate question: Who pulls the trigger?