While the etiology of POEMS syndrome is not known, it is attributed to chronic inflammation (cytokine overproduction) resulting in microangiopathy, edema, increased vascular permeability, and neovascularization. Polyneuropathy, pulmonary hypertension, leukocytosis, and thrombocytosis are possible consequences.
POEMS syndrome should be considered in patients with polyneuropathy and evidence of a monoclonal plasma cell disorder. It is a rare disorder and affects patients predominantly in their fifth and sixth decades of life, with a median age of 51 years and a slight male predominance. While all patients with POEMS syndrome will have polyneuropathy and monoclonal cell disorders, and the vast majority will have osteosclerotic bone lesions, only about two-thirds will have associated skin changes and endocrinopathy. About one-half will have concurrent organomegaly, and about one-third will have fatigue and weight loss. Castleman disease is seen in about 15% of cases.
Criteria used for diagnosis include the following.
Mandatory major criteria:
- Polyneuropathy that is frequently demyelinating (100%)
- Monoclonal plasma cell proliferation (100%) – usually immunoglobulin G (IgG), almost always lambda chain
- Castleman disease (angiofollicular lymph node hyperplasia)
- Marked elevation of serum vascular endothelial growth factor (VEGF) levels
- Extravascular volume overload (ascites, pleural effusions)
- Endocrinopathy that may have affected several glands (67%-84%)
- Bone lesions – usually sclerotic (27%-97%)
- Multiple skin changes (detailed below) (68%-89%)
- Papilledema (29%-64%)
- Thrombocytosis (54%-88%)