Schnitzler syndrome: validation and applicability of diagnostic criteria in real-life patients

BACKGROUND

Schnitzler syndrome is characterized by an urticarial rash, a monoclonal gammopathy, and clinical, histological, and biological signs of neutrophil-mediated inflammation. The aim of this study was to assess the applicability and validity of the existing diagnostic criteria in real-life patients.

METHODS

This multicentric study was conducted between 2009 and 2014 in 14 hospitals in which patients with Schnitzler syndrome or controls with related disorders were followed up. We compared the sensitivities and specificities and calculated the positive and negative predictive values of the Lipsker and of the Strasbourg criteria for the patients with Schnitzler syndrome and for the controls. We included 42 patients with Schnitzler syndrome, 12 with adult-onset Still's disease, 7 with cryopyrin-associated periodic disease, 9 with Waldenström disease, and 10 with chronic spontaneous urticaria.

RESULTS

All patients with Schnitzler syndrome met the Lipsker criteria. According to the Strasbourg criteria, 34 patients had definite Schnitzler syndrome, five had probable Schnitzler syndrome, and three did not meet the criteria. One control met the Lipsker criteria and had probable Schnitzler syndrome according to the Strasbourg criteria. Sensitivity and specificity of the Lipsker criteria were 100% and 97%, respectively. For the Strasbourg criteria, sensitivity for definite and probable diagnosis was 81% and 93%, respectively, with a corresponding specificity of 100% and 97%.

CONCLUSION

Diagnostic criteria currently in use to diagnose Schnitzler syndrome are reliable. More investigations must be done to attest their efficiency in patients with recent-onset manifestations.

Ehlers-Danlos syndrome related to FKBP14 mutations: detailed cutaneous phenotype

In 2012, a new Ehlers-Danlos (ED) variant, characterized by severe progressive kyphoscoliosis, neonatal myopathy and hearing loss, with normal urinary lysylpyridinoline to hydroxylysylpyridinoline ratio and most often a recurrent homozygous mutation in the FKBP14 gene, was reported. Because one of the major affected tissues in ED syndrome is the skin, recognition of the cutaneous features of this newly recognized EDS variant is important. We describe the cutaneous phenotype of an adolescent girl harbouring the recurrent homozygous FKBP14 mutation. Distinctive features included molluscoid pseudotumours and multiple isolated comedones. Molluscoid pseudotumours are a characteristic finding in patients with the classic ED variant, but are rarely reported in other variants. We discuss the cutaneous phenotype of FKBP14-deficient EDS and compare it with other kyphoscoliotic variants.

[Muir-Torre syndrome associated with Waldenstrom's macroglobulinemia]

BACKGROUND

Muir-Torre syndrome (MTS), a cutaneous variant of Lynch syndrome, consists of hereditary predisposition to cutaneous tumours and gastrointestinal and gynaecological neoplasms, with autosomal dominant transmission. It is associated with mutations in genes coding for proteins in the DNA mismatch repair system.

PATIENTS AND METHODS

Herein, we report a case of a male patient presenting Waldenstrom's macroglobulinemia since the age of 50 and which, after the age of 65 years, developed into sebaceous tumours (5 sebaceous adenomas, 1 sebaceoma, 1 sebaceous carcinoma) and colonic lesions (4 adenomas). The clinical phenotype was consistent with MTS. Somatic analysis carried out on one sebaceous tumour showed instability of the microsatellites with loss of expression of MSH2 and MSH6 although constitutional genetic analysis showed no germline mutations known to be harmful.

DISCUSSION

This noteworthy case raises a number of questions, including the possibility of association between STM and Waldenstrom's macroglobulinemia, which is discussed herein.

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.

Efficacy of interferon in recurrent valaciclovir-refractory erythema multiforme in a patient not infected with hepatitis C virus

Recurrent erythema multiforme (EM) is rare and is most typically related to infections with herpes simplex virus. Prophylactic administration of valaciclovir is the first-line treatment, but there is no agreement about second-line treatment in cases of ineffectiveness. We present a 31-year-old man who was not infected with hepatitis C virus (HCV), and had a history of severe and recurrent EM, unresponsive to valaciclovir, colchicine and hydroxychloroquine. The patient noticed that an intermittent flu-like illness seemed to have abrogated an EM flare. Because of this observation, the next EM flares were treated with short courses of interferon, which gave rapid and complete efficacy. Efficacy of interferon in EM has only been reported in two previous patients, in whom the drug was administered to treat HCV infection. Efficiency was attributed to treatment of the underlying HCV infection, which was thought to be the origin of EM in both cases. This is the first case, to our knowledge, reporting a dramatic response to interferon-alfa in a patient who was not infected with HCV.

[Cutaneous panniculitis]

Panniculitis is an inflammation of the subcutaneous fat. Skin biopsy plays a critical role in the differential diagnosis of panniculitis. The most common approach to diagnosis relies on the differentiation between predominantly septal or lobular panniculitis, followed by the distinction between lesions with and without vasculitis. It is also very important to submit a part of the skin biopsy for microbiological analysis and for T-cell clonal expansion if T-cell lymphoma is suspected. Erythema nodosum, the most frequent septal panniculitis, has many causes and in its typical clinical presentation, does not require skin biopsy. In other panniculitis, diagnosis is based on the integration of the clinical and histological data, which renders a deep cutaneous biopsy necessary. Periarteritis nodosa, a septal panniculitis with vasculitis characterized by subcutaneous nodules and livedo racemosa, can be associated with systemic involvement. Nodular thrombophlebitis needs search for associated coagulopathy, Behçet's disease, periarteritis nodosa or Buerger's disease. Lobular panniculitis are classified according to the nature of cells present in the inflammatory infiltrate. If there is a lymphocytic infiltration, lupus panniculitis is difficult to differentiate from subcutaneous panniculitis-like T-cell lymphoma. If there are histiocytes, it can be a sarcoidosis, a cytophagic histiocytic panniculitis or, in newborn, a subcutaneous fat necrosis. Neutrophilic panniculitis needs careful clinic-pathologic correlation. Treatment of panniculitis can be challenging and is based on the histopathological findings. Frequently, the precise cause of panniculitis cannot be established from the outset, so it is important to follow-up patients and not hesitate to repeat the skin biopsy.

[Clinicopathological study of purpura: Is a skin biopsy necessary for palpable purpura?]

OBJECTIVE

For many physicians, palpable purpura is synonymous with vasculitis. However, a skin biopsy is almost always performed in common clinical practice in order to confirm the diagnosis. The aim of our study was to assess whether palpable purpura is always indicative of an inflammatory infiltrate in a vessel wall.

PATIENTS AND METHODS

Eighty-seven patients were included in this prospective monocentric study, 45 of whom were presenting a palpable purpura. Patients were classified in two categories: "leukocytoclastic vasculitis" or "other diagnosis". The clinical and histopathological features of patients with a palpable purpura were studied.

RESULTS

The mean age of patients presenting a palpable purpura was 69 years. There were 26 men and 19 women. Of the 43 patients biopsied, 37 were included in the vasculitis group. The sensitivity, specificity, positive predictive value and negative predictive value for a diagnosis of vasculitis in patients with palpable purpura were respectively 82, 65, 86 and 58 %. The Odds ratio was 8.48 (95 % CI, 2.52-31.80; P<0.05).

CONCLUSION

Most of the palpable purpuras examined were indeed related to leukocytoclastic vasculitis. In the remaining cases, biopsy did not contribute to the diagnosis since it only showed purpura without vessel wall inflammation. In our opinion, a skin biopsy is thus not essential where the clinical presentation is typical.