Polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome is a rare multisystemic disease that occurs in the setting of a plasma cell dyscrasia. The pathophysiologic link between the constellation of symptoms and the underlying disease is not well understood, but the link may be related to changes in the levels of a cytokine or a growth factor. POEMS syndrome was first described by Crow in 1956 and then by Fukase in 1968. The syndrome was termed Crow-Fukase syndrome (by which it is known in Japan) by Nakanishi in a study of 102 cases in Japan.
In 1980, the acronym POEMS was coined by Bardwick et al based on the 5 main features of the disease, namely, polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes.
No specific case definition exists for POEMS syndrome; however, most authors agree that patients with POEMS syndrome should have 3 or more of the 5 features. Some authors have proposed that the presence of 2 major criteria, including a monoclonal plasma-proliferative disorder and polyneuropathy, in addition to the existence of 1 minor criterion, is sufficient for diagnosis. The suggested minor criteria include sclerotic bone lesions, organomegaly, edema, endocrinopathy, papilledema, and skin changes. However, the findings of a retrospective analysis of 629 patients using these criteria suggest that this approach may be inadequate for excluding other disease processes that may account for symptoms and that atypical presentations of POEMS may be misdiagnosed.[1, 2]
The polyneuropathy associated with POEMS syndrome is a bilateral symmetric disturbance. It involves both motor and sensory nerves, begins distally, and has a progressive proximal spread. Associated cranial or autonomic nerves are not involved. Both demyelination and axonal degeneration are noted.[3]
The liver, the lymph nodes, and the spleen are the organs most frequently involved. Enlargement of the lymph nodes and spleen is secondary to changes consistent with Castleman disease (giant angiofollicular hyperplasia, multicentric plasma cell variant) in most patients. Approximately 15% of patients with POEMS syndrome have concomitant evidence of Castleman disease, and both may be associated with glomeruloid hemangioma.[4] Hepatomegaly is not associated with any defined histologic or pathophysiologic changes.
Multiple endocrinopathies have been associated with POEMS syndrome, and most patients have more than 1 endocrine abnormality. Many of the abnormalities noted can be explained by elevations in estrogen levels. Impotence and gynecomastia are common among men. Amenorrhea is common among women. Diabetes mellitus and glucose intolerance are also noted in many patients. Other associated endocrinopathies include hypothyroidism, hyperprolactinemia, and hypoparathyroidism.
POEMS syndrome is seen in the setting of a plasma cell dyscrasia. Although many plasma cell disorders have been reported in patients with POEMS syndrome, most patients are seen with osteosclerotic myeloma or monoclonal gammopathy of unknown significance.
The M proteins most frequently found are the immunoglobulin A (IgA)–gamma and immunoglobulin G (IgG)–gamma light chains. In a case report of one patient with POEMS syndrome,[5] serum electrophoresis demonstrated an M-band with isolated IgA heavy chain but no abnormal light chain, which could suggest abnormal secretion of monoclonal protein or the rare possibility of coincidental heavy-chain disease in association with POEMS syndrome. A single case of POEMS syndrome in association with Waldenström macroglobulinemia,[6] characterized by immunoglobulin M–kappa paraproteinemia, has been reported. Classic multiple myeloma has not been associated with the disease. The type of plasma cell disorder has not been shown to be correlated with the constellation of symptoms noted in patients with POEMS syndrome.
Multiple dermatologic changes have been associated with POEMS syndrome. The most common changes include hyperpigmentation, skin thickening, sclerodermoid changes, and hypertrichosis. Other skin changes, including whitening of the proximal nail (Terry nails), peripheral edema, hyperhidrosis, clubbing of the fingers, Raynaud phenomenon, and angiomas, have been observed.
Other signs and symptoms associated with POEMS syndrome include papilledema, anasarca, pleural effusions, ascites, fever, thrombosis, renal insufficiency, and diarrhea.
The pathophysiology of POEMS syndrome is not well understood. In all patients, a plasma cell disorder underlies the development of the syndrome; however, the mechanism by which this occurs is unknown. Elevations of cytokines, such as interleukin (IL)–1beta, IL-6, and tumor necrosis factor (TNF)–alpha, have all been noted.
Most recently,[7] significant elevations in vascular endothelial growth factor (VEGF) levels have been noted. Increases in VEGF levels have been postulated to lead to enhanced vascular permeability, leading to the associated edema, increased endoneural pressure, and deposition of plasma cell–derived material. As myelin is exposed to serum cytokines and complement, demyelination can occur. In one case report of a patient with POEMS syndrome and bilateral cystoid macular edema, macular thickness varied with serum VEGF levels. After vitrectomy and an intraocular triamcinolone injection, decreased macular thickness was associated with lower intraocular VEGF levels. The authors proposed that elevated VEGF levels may be causally related to cystoid macular edema in persons with POEMS syndrome. Stimulated vascular proliferation has also been postulated to result in some of the skin changes associated with the disease.
VEGF may also play a role in bone metabolism, as suggested by a study of 2 patients who received high-dose therapy (HDT) with autologous stem cell transplantation.[8] In this study by Kastritis et al,[9] decreasing VEGF levels corresponded with both clinical improvement and the normalization of bone metabolism as measured by multiple remodeling indices.
In a study of 22 patients with POEMS, hyperalgesia was correlated with an elevation of proinflammatory cytokines (IL-1beta, IL-6, and TNF-alpha), in addition to the electrophysiologic reduction of sensory nerve action potentials and the histopathologic loss of myelinated fibers.[10] Serum levels of other growth factors, including epidermal growth factor, fibroblast growth factor, and platelet-derived growth factor, are not increased in patients with POEMS syndrome. Because POEMS syndrome is associated with Castleman disease and angioma formation, a role for human herpesvirus 8 (HHV-8) has been postulated; however, early studies have not demonstrated an association.
All cases of POEMS syndrome are associated with a plasma cell disorder. The syndrome has been seen in association with osteosclerotic myeloma, monoclonal gammopathy of unknown significance, and Waldenström macroglobulinemia, but not with classic multiple myeloma. The reason plasma cells in some dyscrasias produce factors that cause POEMS syndrome while others do not is not clear. The mechanism by which plasma cells lead to POEMS syndrome is not understood; however, elevations in IL-1beta, IL-6, TNF-alpha, and VEGF levels have been implicated.
POEMS syndrome is rare. Several hundred cases have been described in the literature; however, the incidence may be underreported because the syndrome may go unrecognized.
No specific racial association has been identified, although a preponderance of cases have been reported in the Japanese literature.
POEMS syndrome is slightly more prevalent among men than women, with a male-to-female ratio of 2.5:1.
The onset of POEMS syndrome occurs most frequently in the fifth or sixth decade of life, with a mean patient age at onset of 48 years for men and 59 years for women. In 2007 and 2008, however, POEMS syndrome has been reported to occur in two 15-year old patients.[11, 12]
The prognosis depends on the extent of the underlying plasma cell disorder and its response to treatment. The prognosis is best for patients with a single lytic lesion. The prognosis is worst for patients with a plasma cell disorder involving the bone marrow.[13] Patients with multiple lytic bone lesions have an intermediate prognosis. When the plasma cell disorder responds to treatment, all other symptoms usually improve or resolve completely. Reduced survival times are associated with the presence of cough, and respiratory weakness decreased mean survival time from 139 months to 87 months in one study.[14]
The morbidity associated with POEMS syndrome depends on the systems involved and ranges from skin pigment alteration to debilitating weakness and loss of function. The median survival period for patients with POEMS syndrome is 8 years. The natural course of POEMS syndrome is chronic, with a reported median survival of approximately a decade (8-13.8 y). In their review, Miralles and colleagues[15] reported a 5-year survival rate of 60%.
Overall shorter survival has been associated with extravascular volume overload (eg, effusions, edema, ascites) and fingernail clubbing. Cardiorespiratory failure, renal failure, infection, and progressive inanition are among the most common causes of death. The neurologic sequelae of POEMS syndrome cause approximately 50% of the patients with POEMS syndrome to become bedridden. Death may also occur as a consequence of decubitus ulcers and thromboses due to inactivity, organomegaly, and endocrinopathy, rather than as a consequence of the aggressiveness of the monoclonal protein.
Presenting symptoms vary based on the organ systems involved. Frequent presentations include the following:
Patients may also report the following:
Skin manifestations are as follows:
Neurologic manifestations are as follows:
Cardiovascular manifestations are as follows:
Endocrine manifestations are as follows:
Pulmonary manifestations are as follows:
Other extracutaneous manifestations are as follows:
When POEMS syndrome is suggested clinically, perform a range of laboratory studies to define the extent of involvement and to establish whether other organ systems are involved.
Patients commonly have thrombocytosis with or without polycythemia.
Hypercalcemia and renal insufficiency are rarely present.
Generally, the M protein is IgG-gamma or IgA-gamma and small in size (median, 1.1 g/dL).
Serum protein immunoelectrophoresis is used to define the nature and the extent of the monoclonal gammopathy.
Thyrotropin levels, fasting blood glucose levels, a glucose tolerance test, and estrogen levels can be used to screen for endocrinopathy.
In patients with neuropathy, cerebrospinal fluid test results either are in the reference range or may show elevated levels of protein.
Erythrocyte sedimentation rate results are in the reference range or slightly elevated.
Cerebrospinal fluid may demonstrate a cytoalbuminologic dissociation.
For research purposes, cytokine and growth factor levels can be measured. Based on past studies, TNF-alpha, IL-6, IL-1beta, and VEGF levels are usually elevated, while epidermal growth factor, fibroblast growth factor, and platelet-derived growth factor levels are within the reference range.
Although rare, it has been suggested that POEMS syndrome may increase the risk of potentially lethal calciphylaxis. Follow-up on the potential occurrence of this symptom is advisable.[21]
Plain film radiographs are useful for locating lytic bone lesions caused by osteosclerotic myeloma.
At least 95% of patients have osteosclerotic lesions, with more than half the patients having multiple lesions. Both osteosclerotic and osteolytic lesions may be present and may be of modest size.
Bone marrow biopsy may be indicated because as many as 10% of patients have marrow involvement with plasma cells.
Lymph node biopsy is indicated in patients with lymphadenopathy and, in most patients, demonstrates findings of Castleman disease. HHV-8 has been demonstrated within the lymphocytes of some of these lymph node biopsy specimens, in addition to being present within endothelial cells and lymphocytes in the glomeruloid hemangioma skin biopsy specimen.[22, 23] Within the HHV-8 genome, a viral homologue to human IL-6 is present, which is believed to induce angiogenesis and hematopoiesis. However, some patients test negative for HHV-8,[24] so the complete role of this virus in the pathogenesis of Castleman disease is unknown.
Electromyography exhibits findings consistent with polyneuropathy, prominent demyelination, and features of axonal degeneration. One study demonstrated a statistically significant pattern of lower limbs having absent or attenuated amplitudes of compound muscle action potentials and absent sensory nerve action potentials compared with upper limbs. Intermediate nerves segments exhibited abnormal conduction slowing compared with distal portions. These patterns may aid in early diagnosis.
Nerve biopsies usually reveal evidence of both axonal degeneration and demyelination, characterized by uncompacted myelin lamina without immunoglobulin deposition and minimal cellular infiltration.
The histopathologic changes seen in the sclerodermoid lesions are nonspecific, showing hyperpigmentation of the basal layer with an inflammatory infiltrate or dermal fibrosis. Other reports have noted vascular prominence. Sweat glands and collagen are normal, differentiating this condition from scleroderma. A skin biopsy of hyperpigmented lesional skin may demonstrate a nonspecific inflammatory infiltrate composed of a lymphoplasmacytic population.[25]
Most angiomas seen in persons with POEMS syndrome are histologically consistent with cherry angiomas. The angiomas in a small proportion of patients have the appearance of a glomeruloid hemangioma.[26] This finding may be strongly suggestive of POEMS syndrome, but it is not pathognomonic because the presence of this pathologic entity has been reported in a patient without POEMS syndrome. Multiple ectatic vascular spaces with luminal clusters of congested capillaries are noted in the lesions. The capillaries are surrounded by pericytes and resemble renal glomeruli, hence the term glomeruloid hemangioma.
A study of bone-marrow histology in 87 patients from the Mayo Clinc concluded that the constellation of lambda-restricted monoclonal gammopathy, plasma cell rimming around lymphoid aggregates, and megakaryocytic hyperplasia in bone marrow is highly suggestive of POEMS syndrome, especially in the context of a peripheral neuropathy.[27]
The treatment of POEMS syndrome depends on the treatment of the underlying plasma cell disorder. Most patients are treated with a combination of medical, surgical, and adjuvant therapies.[28]
The current mainstays of treatment for patients with diffuse disease include combinations of corticosteroids, low-dose alkylators, and peripheral blood stem cell transplantation following high-dose chemotherapy.[29, 30] Some caution should be used in selecting the chemotherapeutic regimen to avoid worsening of the polyneuropathy.
Widespread osteosclerotic lesions may benefit from systemic therapy, with approximately half the patients benefiting from melphalan and prednisone. Although about a quarter of patients respond to corticosteroids, relapses are common without additional treatment of the underlying plasma cell disorder. Intravenous immunoglobulin and plasmapheresis have not shown therapeutic benefit.
In a study from China, 31 patients received 12 cycles of oral melphalan (10 mg/m2 body surface area [BSA]) plus oral dexamethasone (40 mg/d) on days 1-4 of every 28 days.[31] Prophylaxis with a proton-pump inhibitor was added days -1 to 5. Doses were adjusted according to side effects and renal function. Good hematologic and neurologic responses were reported.
Some patients may consider high-dose chemotherapy followed by autologous hematopoietic stem cell transplantation. Preliminary studies report a mortality rate of 7.4% associated with the procedure, in addition to significant peritransplantation morbidity that often requires intubation, but nearly all survivors experienced benefit. A case report described the successful treatment of a patient with multicentric Castleman disease and POEMS syndrome with autologous hematopoietic stem cell transplantation, with subsequent improved nerve conduction and normalization of serum protein electrophoresis results.[32]
Treatment with high-dose chemotherapy followed by autologous peripheral blood stem cell transplantation may result in clinical improvements of polyneuropathy.[33]
Relapse after successful auto peripheral blood stem cell transplantation has been reported.[34]
A 2014 multicenter retrospective study in Japan has shown positive results for autologous stem cell transplantation (ACST) in the treatment of patients with POEMS syndrome in terms of long-term survival and quality of life.[35]
In a series of 30 POEMS syndrome patients treated at the Mayo Clinic in Rochester, Minn, engraftment syndrome was reported in approximately half the patients, with symptoms including fever (93%), diarrhea (77%), weight gain (53%), and rash (43%), in addition to a 3% treatment-related mortality rate. Baseline splenomegaly was predictive of a complicated peritransplantation course.[36]
Kojima et al[37] describe clinical remission of more than 20 months for one patient who received high-dose chemotherapy with autologous CD34+ -purged stem cells.
The clinical course of one patient improved after administration of thalidomide, which has well-described antiangiogenetic, antiproliferative, and anticytokine characteristics.[38]
A case report of one patient with POEMS syndrome and elevated VEGF levels describes successful treatment with bevacizumab, an antiangiogenesis monoclonal antibody directed against VEGF. This treatment was associated with reduced edema and less painful neuropathy.[39] Another patient treated with bevacizumab (10 mg/kg) twice monthly had decreased pain after one month, with improvements in breathing and walking within 10 weeks. These subjective changes were associated with a drop in VEGF levels and clinical improvements measured by pulmonary function tests, electromyographic studies, and nerve conduction studies. In this patient, neither hepatomegaly nor skin abnormalities were modified.[40]
Responses to bevacizumab reportedly have been variable. In one patient treated 7 years after diagnosis, no clinical improvement was reported despite lowered VEGF levels, which the authors thought may be due to aberrant angiogenesis that had already developed systemically.[41] Another POEMS patient treated with 2 courses of bevacizumab (5 mg/kg) had decreased VEGF levels but worsening paresis, and this patient developed severe capillary leak syndrome with edema, ascites, and pleural effusion. These authors encourage caution prior to starting bevacizumab therapy because a sudden decrease in VEGF levels may result in apoptosis of endothelial cells, possibly increasing capillary leakiness.[42] This approach is supported by another report of a patient treated by bevacizumab who developed diarrhea, generalized edema, pulmonary hypertension, and systemic inflammation and who subsequently died from multiorgan failure.
One patient improved after receiving 9 cycles of lenalidomide given daily for 21 days of a 28-day cycle with once-weekly dexamethasone. The dosage of lenalidomide was gradually increased from 15 mg to the standard 25-mg dose. Lenalidomide is cytotoxic to malignant plasma cells in addition to being immune modulatory.[43] In 2009, a case report also described lenalidomide therapy in a patient with kappa restriction.[44] A 2015 prospective phase II trial of lenalidomide combined with dexamethasone (LEN-DEX) reported a promising reduction of VEGF to normal levels and recovery of neurological function in many patients, with minimal adverse effects.[45]
Sanada et al[46] report the clinical remission and correspondingly decreased VEGF serum concentrations of one patient with POEMS syndrome and renal lesions after treatment with high-dose melphalan therapy followed by autologous blood stem cell transplantation.
A single patient with POEMS syndrome associated with 2 monoclonal gammopathies (IgG-kappa and IgA-gamma) has been reported, in whom high doses of all-trans -retinoic acid was potentially beneficial.[47]
Two case reports describe successful therapy with bortezomib.[48, 49]
For patients with POEMS and pulmonary hypertension, high-dose steroid treatment appears to provide improvement as confirmed by sequential hemodynamic studies.[50, 51]
Surgical excision of isolated plasmacytomas may result in complete resolution of the syndrome.
Radiation therapy of solitary osteosclerotic lesions is first-line therapy for patients with an isolated plasmacytoma.
Radiation therapy in dosages of 40-50 cGy to limited areas can improve osteosclerotic lesions in more than half the patients. More than 6 months may elapse before clinically apparent improvement is observed, with benefit observed even 2-3 years after therapy. Other authors recommend systemic therapy for patients whose disease process fails to stabilize 3-6 months after completing radiation therapy.
Care of patients with POEMS syndrome is coordinated through many specialists because of the extent of possible symptoms associated with the disorder.
Once the diagnosis is clinically suggested, the patient should be evaluated by a neurologist, a hematologist, a dermatologist, and an endocrinologist to define the extent of disease.
Referral to a pulmonologist or a nephrologist should be guided by the patient's symptomatology.
A surgeon or a radiation oncologist may be needed for coordination of treatment.
Even if the plasmacytoma completely responds to treatment, patients need long-term follow-up care because some symptoms, such as neurologic defects and functional loss due to tightening of the skin, may be permanent.
The goal of pharmacotherapy is to reduce morbidity in patients whose disease does not respond to surgical removal or radiation therapy of the plasmacytoma.
Clinical Context: Prednisone is useful in many inflammatory and autoimmune conditions. It must be metabolized to the active metabolite prednisolone for effect. Conversion may be impaired by liver disease. Prednisone may decrease inflammation by reversing increased capillary permeability and suppressing PMN activity.
These agents have anti-inflammatory properties and cause profound and varied metabolic effects. In addition, they modify the body's immune response to diverse stimuli.