Polycythemia vera and stiff-person syndrome: a case report

Polycythemia vera (PV) is a myeloproliferative neoplasm, characterized by trilineage hypercellularity, which increases the risk of thrombosis. Stiff-person syndrome (SPS) is a very rare autoimmune neuronal excitability disorder, in which antibodies disrupt the balance between excitatory and inhibitory neurotransmitters, leading to stiffness and spasms of agonist and antagonist muscles.

This report describes the first known case of PV and SPS occurring simultaneously in a middle-aged male patient. He presented with back stiffness and painful abdominal spasms and was found to have erythrocytosis incidentally. He had high JAK2 V617F mutation burden and was positive for anti-GAD65 antibody. Progressively intensified therapy was given until his symptoms resolved.

This case highlights the diagnostic and therapeutic challenges of these conditions as well as the need for further exploration of potential shared molecular mechanisms between PV and SPS.