PO113 | A STRANGE CASE OF RECURRENT ISOLATED DIGITAL ARTERIAL THROMBOSIS

M.M. Poggi, D. Bruni | SOC Medicina 1, Nuovo Ospedale Prato, Prato, Italy

Background. Arterial thrombosis is a leading cause of morbidity and mortality, sometimes occurring in uncommon sites without a readily apparent etiology. Polycythemia vera (PV) is a chronic myeloproliferative neoplasm due to a JAK2 gene variant and frequently characterized by arterial and venous thrombosis, even in atypical sites. Diagnosis requires specific Hb and HCT cutoffs along with low EPO level, but BM biopsy is highly recommended. Low dose ASA is suggested for all patients with PV. Cytoreductive therapies can be used in addition to aspirin and phlebotomy for patients with prior thrombosis to reduce thrombotic risk.
Case Report. We present the case of a 65 years old male patient with relapsing isolated digital arterial thrombosis. Patient was admitted in November 2025 to our hospital for an acute digital ischemia of the 4th finger of the left hand while on therapy with Rivaroxaban 10 mg OD for the extended prophylaxis of an idiopathic VTE episode. A CT angiography of the aorta excluded embolism, dissection and neoplastic lesions, so the patient was discharged with coumadin with an appointment to our ambulatory service for further diagnostic testing. However, after a few days he was re-admitted to ED for a recurrent thrombosis in the same site, so he was referred to our internal medicine department. The patient's medical history included multiple unprovoked VTE episodes treated with various antithrombotic regimens. There was no history of smoking or drug use, nor hypertension. The patient had a gastric NET treated with total gastrectomy, with persistently negative follow-up. Color doppler US confirmed obstruction of the 4th interdigital artery. Lab test showed negativity of APLAs (LA, aCL IgM-IgG, aβ2GPI IgM-IgG) and the whole autoimmune panel (ANA, ENA, ANCA, crioglobulins, C3/C4, HLA-B51). Both APCR and the G2021A prothrombin gene polymorphism were negative. Homocysteine ​​was only modestly increased (23 μmol/L), while glycemic and lipidic profile were in range according to ADA and ESC targets, respectively. Gastroscopy, colonoscopy and PSA were all negative, while serum protein electrophoresis demonstrated hypergammaglobulinemia with no evidence of a monoclonal component. Contrast-enhanced whole-body CT scan showed only a moderate splenomegaly but excluded cancer, vasculitis, dissection or aTOS. 18F-FDG-PET showed a moderate BM uptake without a morphological lesion on CT. TTE showed no vegetations or thrombi, and ambulatory ECG monitoring revealed no AF or flutter. VKA was stopped in favor of therapeutic UFH, with rapid remission of symptoms. After 7 days, we switched back to coumadin and added aspirin 100 mg without further relapse. Since lab tests led to inconclusive diagnosis, considering the findings described above, we investigated the JAK2 V617F mutation which was positive. Subsequent BM examination confirmed the diagnosis of PV. A treatment based on hydroxyurea was started along with DAT (coumadin + aspirin). TTR at 1 year was very good (> 90%), and patient didn’t have thrombotic recurrence nor evidence of major bleeding or CRNMBs.
Conclusions. Unexplained recurrent arterial thromboses in unusual sites are rare, yet they offer an interesting diagnostic challenge requiring a systematic approach. Once most common causes have been ruled out, rarer causes must be addressed. Among these, PV is condition at high thrombotic risk. However, once correctly diagnosed, treatment can prevent relapse in the majority of patients.