Manifestations cutanées associées aux paraprotéines: mécanismes des atteintes cutanées

Monoclonal gammopathy of cutaneous significance: review of a relevant concept

Some dermatologic entities are strongly associated with the presence of a monoclonal gammopathy. They should be referred to as monoclonal gammopathy of cutaneous significance (MGCS). A short review of the main entities that fit into the spectrum of MGCS is provided. Amyloidosis, macroglobulinoderma and follicular hyperkeratotic spicules result from extravascular immunoglobulin or immunoglobulin-related protein deposition. Skin findings include papules and plaques, follicular spicules, purpura, haemorrhagic bullae, macroglossia and nail changes. The skin findings in cryoglobulinemia (CG) result from vascular immunoglobulin deposition, either as immune complexes within the vessel walls in mixed CG or within the lumina of small vessels in monoclonal CG. Mixed CG manifests as palpable purpura of leukocytoclastic vasculitis, and monoclonal CG as stellar and/or retiform purpura that can evolve into extensive skin necrosis. In some rare instances, immunoglobulins have a specific biological activity. This is, for example, the case when they bind lipoproteins that precipitate and induce hypocomplementemic xanthomas. Xanthoderma related to antiflavin activity of the monoclonal component or acquired angioedema related to anti-C1INH activity is other example. Abnormal cytokine secretion is the hallmark of some entities. High vascular endothelial growth factor levels correlate with some of the skin manifestations of the Polyneuropathy organomegaly endocrinopathy monoclonal component skin changes syndrome, such as hypertrichosis or the adenopathy and extensive skin patch overlying plasmacytoma syndrome. All the clinical manifestations of the Schnitzler syndrome are IL-1 mediated. In other MGCS, such as scleromyxedema, Clarkson syndrome, TEMPI syndrome, cutis laxa and the neutrophilic dermatoses, the link between the monoclocal component and the entity is clearly established, but not understood so far.

Multiple myeloma-associated skin light chain amyloidosis: A case of misdiagnosis

The present study reports the case of a 42-year-old male with multiple myeloma (MM)-associated skin light chain amyloidosis who presented with skin purpura as the initial symptom, which was misdiagnosis as Henoch-Schönlein purpura nephritis prior to admission to the Second Xiangya Hospital (Changsha, Hunan, China). The patient presented with purpura, papules petechiae and spontaneous ecchymosis, which was located scattered around the neck, chest and limbs, accompanied by a small amount of bleeding in the conjunctival and oral mucosa, and a swollen tongue. Upon laboratory examination, the serum immunological change showed increased serum immunoglobulin G and λ light chain levels, and a urine Bence Jones protein level of >1 g/24 h. This was accompanied with an abnormal result for immunofixation electrophoresis, and positive staining with Congo red showing apple-green birefringence in skin biopsy specimens. Thus, the patient was diagnosed with MM-associated skin amyloidosis with the initial symptom of skin purpura. Following treatment with chemotherapy consisting of prednisone and bortezomib, the skin lesions markedly improved. The present study indicates that the presentation of skin purpura in systemic amyloidosis associated with MM may be an important aid in the diagnosis and direct treatment of this disease in the clinic.

[Dermatological manifestations of monoclonal gammopathies: contribution of cutaneous histopathology]

Skin manifestations associated with monoclonal gammapathy are common and can present with various clinical and pathological aspects. They can be the first events leading to the diagnosis of monoclonal gammapathy. They may be present either as specific lesions, including lymphoplasmacytic or pure plasma cell neoplastic infiltrates and monoclonal immunoglobulin deposits, or as non-specific dermatitis, such as leukocytoclastic vasculitis, neutrophilic dermatoses, mucinoses or xanthomatosis, giving little clues for the diagnosis of the underlying disease.

Clinico-biological characteristics and treatment of type I monoclonal cryoglobulinaemia: a study of 64 cases

This retrospective analysis was conducted in 64 patients diagnosed with type I cryoglobulinaemia (CG) followed at two French centres. Median follow-up was 6·75 years. CG was IgG in 60% and IgM in 40% of all cases and was asymptomatic in 16 patients (25%). Cold-triggered ischaemic skin manifestations were observed in 33 patients (51%). Neurological manifestations were observed in 15 patients and renal manifestations in 13. Most of the patients with necrotic purpura (14/16, P = 0·009) and renal manifestations (11/13, P = 0·057) had IgG CG. IgG CG was associated with monoclonal gammopathy of undetermined significance (MGUS), myeloma, chronic lymphocytic leukaemia and lymphoplasmocytic lymphoma in 18, 13, 5 and 2 patients, respectively. IgM CG was associated with MGUS and Waldenström macroglobulinaemia in 8 and 18 cases, respectively. One third of patients did not receive any specific treatment. Various treatments, including rituximab, were administered to 25/31 patients with IgG CG and 6/25 patients with IgM CG due to CG-related symptoms. Rituximab was ineffective in all cases associated with a predominantly plasmacytic proliferation. To conclude, type I CG has specific clinico-biological characteristics compared to type II CG. Furthermore, there are differences in terms of related manifestations between type I IgG and type I IgM CG.

[Skin manifestations of monoclonal gammopathies]

Whatever their aetiology, monoclonal gammopathies can be associated to several clinical features. Mechanisms are various and sometimes unknown. Skin is frequently involved and may represent a challenging diagnosis. Indeed, skin manifestations are either the presenting features and isolated, or at the background of a systemic syndrome. Our objective was to review the various skin manifestations that have been associated with monoclonal gammopathies.

Paraneoplastic cutaneous leukocytoclastic vasculitis disclosing multiple myeloma: a case report

Cutaneous lesions are unusual during the course of multiple myeloma. In rare cases, multiple myeloma may be associated to skin involvement secondary to amyloidosis, cryoglobulinemia, and POEMS syndrome. Paraneoplastic skin involvement occurs preferentially during solid neoplasms. We report the case of an uncommon presentation of an IgA lambda multiple myeloma in a 58 year-old woman preceded by vascular purpura with cutaneous leukocytoclastic vasculitis (LV) and intense deposit of IgA and kappa light chains in the dermal vessels. Purpura resolved after specific treatment of multiple myeloma and diagnosis of paraneoplastic purpura was asserted. We propose a brief review of the literature about skin involvement during multiple myeloma. This case highlights the necessity to search for MM when we are facing a LV.