Osteosclerotic myeloma and POEMS syndrome

Osteosclerotic bone lesions are seen in about 3% of patients with multiple myeloma.6768 Patients with osteosclerotic myeloma are on average about 10 years younger than those with classic myeloma, with a mean age at diagnosis of 55 years. Male gender predominates. The incidence of anemia, renal failure, hypercalcemia, and bone pain is lower than in classic myeloma. Monoclonal protein concentration is usually low. Osteosclerotic bone lesions are often limited in number, and bone marrow plasmacytosis is mild or absent. Peripheral polyneuropathy, however, occurs in 40-50% of patients and may precede other symptoms of myeloma.65 68 Similarly, multiple myeloma that is associated with polyneuropathies occurs at a younger age with a male predominance. In about 50% of cases, pure osteosclerotic or mixed sclerotic/lytic bone lesions are seen, although pure lytic lesions occur in about 25% of patients.42 69 In both groups, the monoclonal IgG or IgA are almost exclusively associated with X light-chain isotype. Clearly, these two groups of patients exhibit similar and overlapping features. Other unusual clinical manifestations, variably expressed in these patients, include organomegaly, endocrinopathy, and skin lesions. This constellation of clinical features is emphasized by the designation of an acronym, POEMS (plasma cell dyscrasia with polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes) syndrome.7071 For uniform diagnosis, it was recently proposed that a diagnosis of POEMS be made when a patient meets two major criteria—polyneuropathy and monoclonal plasmaprolif-erative disorder—and one of the minor criteria—sclerotic bone lesions, Castleman's disease, organomegaly (liver, spleen, lymph nodes), endocrinopathy (adrenal, thyroid, pituitary, gonads, parathyroid, pancreas), skin changes (hyperpigmentation, hypertrichosis, plethora, hemangiomata, white nails), and papilledema.72 The POEMS syndrome is associated with various plasma cell dyscrasias. The incidence was 1.4% in 2714 patients with plasma cell dyscrasias, excluding myeloma.73 Five to 20% of POEMS syndrome occurs in patients with typical myeloma with significant bone marrow plasmacytosis. Osteosclerotic or mixed scle-rotic/lytic bone lesions occur in 90%. In about 45% of patients, the bone lesion is solitary.74 The neuropathy in POEMS syndrome, form extensive demyelination with various degree of axonal degeneration, resembles chronic inflammatory demyelinating polyneuropathy. In the great majority, it is a chronic, distal sensorimo-tor neuropathy with symmetrical numbness and dysesthesia of legs, progressively extending proxi-mally, accompanied by ascending weakness. Reflexes are severely depressed. Cranial nerves are spared, and autonomic involvement is very rare.7576

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