Although plasma cell neoplasms occupy a large place in hematology practice, POEMS syndrome is very rare. Serum lambda light chain elevation and polyneuropathy, together with organomegaly, endocrinopathy, and skin lesions are the main components of the syndrome. We share our case, which we diagnosed in our clinic, with the belief that it will contribute to the literature.

A 51-year-old male patient, who had no history of co-morbidity, drug use, or exposure to toxic substances, was started on supportive treatment in February 2021, who first developed the complaint of impotence. Later, he applied to the neurology outpatient clinic with complaints of weakness and weakness in the feet. After detecting polyneuropathy in his evaluation, IgG Lambda monoclonal gammopathy was detected in serum immune electrophoresis in his evaluation for etiology.

Thereupon, it started to be investigated in terms of plasma cell neoplasms. In the examinations performed, immunoglobulin levels, serum-urine kappa and lambda light chain levels, plasma increase in the bone marrow biopsies and a solitary 3.3 cm sclerotic lesion in the sacral region were detected in the PET-CT of the patient, whose ethology could not be diagnosed.

A tru-cut biopsy was taken from the sclerotic lesion of the patient, who was thought to be a plasmacytoma and a 20% monoclonal IgG lambda plasma increase was detected. In his physical examination, it was seen that he had increased lesions (Figure-1) and acrocyanosis (Figure-2) on the skin for the last 3-4 months. The patient's current complaints and laboratory results were evaluated with a preliminary diagnosis of POEMS syndrome (Table-1).

POEMS syndrome is a rare disease and its exact incidence is unknown. It is frequently seen in 5-6 decades, with a median age of 51 years, and 63% of cases are male patients [1]. Chronic and excessive production of proinflammatory and other cytokines (IL-1β, TNFα, IL-6, vascular endothelial growth factor (VEGF) etc.), microangiopathy, edema, effusions, increase in vascular permeability, increase in neovascularization are important in the pathophysiology of the disease.