The first report of a JAK2 V617F-positive myeloproliferative neoplasm with initial manifestation as a rare pampiniform venous plexus thrombosis and review of the literature.

Pampiniform venous plexus (PVP) thrombosis is exceedingly rare, with fewer than 25 cases described. Thus, the etiology and pathophysiology remain largely unknown. A 38-year-old male with no known risk factors incidentally noted a 10-day history of right testicular discomfort prompting evaluation. Findings included extensive right PVP thrombus, critically elevated hematocrit, and a JAK2 V617F gene variant. Despite no treatment guidelines, conservative management was initiated with therapeutic apixaban, and therapeutic phlebotomy and hydroxyurea for newly diagnosed primary polycythemia vera (PV), sparing exploratory genitourinary surgery. This represents the first reported case of PVP thrombosis as the initial manifestation of a JAK2 V617F positive PV and the first documented report of PVP thrombosis associated with an acquired hypercoagulable state. Of the 8 previous cases with hypercoagulable testing performed, 2 involved inherited hypercoagulable states, suggesting hereditary and acquired prothrombotic disorders should be considered as predisposing factors. Testing for the JAK2 V617F variant in patients with mesenteric, cerebral, and splanchnic venous thromboses is currently recommended, but testing patients with venous thromboses in other anatomical locations remains controversial. We reviewed all previously described cases to expound upon this diagnosis, potential association with hypercoagulable disorders, treatment options, and observed clinical outcomes. This case adds to the minimal literature and supports genetic testing all patients with spontaneous PVP thrombosis for the JAK2 V617F variant and other hypercoagulable conditions. Additionally, conservative management with therapeutic anticoagulation and treatment of the underlying precipitating disease state may be acceptable in select patients, following exclusion of surgical emergencies.