Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal Protein, and Skin Changes (POEMS) Syndrome Presenting With Superior Mesenteric and Portal Vein Thrombosis: A Case Report.

Polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and skin changes (POEMS) syndrome is a rare paraneoplastic disorder associated with plasma cell dyscrasia and multisystem involvement. This report describes a case of splanchnic venous thrombosis presenting as the initial clinical manifestation. A 38-year-old woman presented with acute abdominal pain associated with progressive polyneuropathy. Imaging studies revealed extensive thrombosis of the superior mesenteric vein with extension into the portal vein, moderate ascites, hepatosplenomegaly, and diffuse osteosclerotic bone lesions. Laboratory investigations demonstrated an immunoglobulin A (IgA) lambda monoclonal gammopathy. Positron emission tomography-computed tomography showed widespread hypermetabolic osteosclerotic lesions, hypermetabolic axillary lymphadenopathy, and increased cardiac uptake. Transthoracic echocardiography revealed right ventricular dilation with an intermediate probability of pulmonary hypertension. The overall clinical, radiological, and laboratory findings were consistent with disseminated POEMS syndrome. This case illustrates a rare initial presentation of POEMS syndrome manifesting as splanchnic venous thrombosis. It emphasizes the importance of considering POEMS syndrome in patients with unexplained portal hypertension or atypical venous thrombosis in the presence of systemic manifestations.