POEMS syndrome

Clinical History

The patient presented with diffuse erythrodermia, hepatosplenomegaly, adenopathy and peripheral neuropathy. Transaxial CT showed bone sclerosis in the distal portion of the femur and a lytic lesion with a sclerotic rim in the sacrum.

Imaging Findings

The patient presented with thoracic pains, diffuse erythrodermia and increased haematocrit level. Examination revealed hepatosplenomegaly and subclavicular bilateral adenopathy. The patient complained of diffuse paresthesias in the lower limbs, and deep tendon reflexes were absent. Peripheral neuropathy was confirmed by electromyography. Endoscopy of the stomach showed erosive congestive gastritis. Haemoglobin was at 170g/l and platelets at 560x10⁹/l. Serum electrophoresis results were normal but immunofixation showed an IgG kappa M component.

Conventional radiography and CT (Figs 1,2 ) showed osteosclerosis in the distal portion of the right femur and a lytic lesion with a sclerotic rim in the right sacrum. Biopsy of the sacral tumour was performed and revealed proliferation of tumoral plasma cells.

Discussion

The syndrome now known as POEMS was first described by Crow in 1956 and later by Fukase in 1968. It was given the name of Crow-Fukase syndrome by Nakanishi. POEMS syndrome is more common in men than in women and the average age of involved patients is about 46 years.

It is a multisystemic syndrome associated with plasma cell dyscrasia characterised by the combination of Polyneuropathy (chronic inflammatory demyelinating neuropathy), Organomegaly, Endocrinopathy, M-protein, and Skin changes (hyperpigmentation, skin thickening, hypertrichosis). Other signs are frequently observed in affected patients, such as peripheral oedema, anasarca, diarrhoea, weight loss, finger clubbing, arteriopathy, nephropathy and thrombocytosis. The plasma cell dyscrasia that causes POEMS syndrome differs from the dyscrasia found in multiple myeloma. The light chain of the M-protein is always l, the heavy chain is a in 50% of patients.

POEMS syndrome, with a 5-year survival of 60%, has a better prognosis than that of multiple bone myeloma. However, this high rate is largely due to cases where POEMS syndrome is secondary to plasmocytoma. In these patients, local treatment (surgery and/or radiotherapy) can cure the disease. POEMS syndrome is certainly a paraneoplastic phenomenom mediated by a soluble mediator produced by abnormal plasma cells. VEGF is thought to play an important role in the pathophysiology of this syndrome.

Two types of radiographic features may be observed in POEMS syndrome: focal bone lesions and bony proliferation.

Focal bone lesions can be solitary (55%) or multiple. The most frequent sites are the pelvis and the spine, although other sites may be involved (long bones, cranial vault, ribs). The imaging features commonly observed are uniformly sclerotic or mixed lytic-sclerotic lesions (lytic centre with a sclerotic rim). In some patient, an ivory vertebra or features similar to those of bone islands may be observed. Purely lytic lesions do occur but are unusual.

Bony proliferation at sites of tendon and ligament attachment also can be seen. Particularly characteristic are irregular bony excrescences involving the spine, particularly the posterior elements (Resnick). Enthesopathic abnormalities also may appear in obturator rings, margins of the sacrum and ilium, along the tibia and fibula.

Differential Diagnosis List

Final Diagnosis

POEMS syndrome

URL:	https://www.eurorad.org/case/1972
DOI:	10.1594/EURORAD/CASE.1972
ISSN:	1563-4086