Clinical Features and Treatment Outcomes of Patients With Necrobiotic Xanthogranuloma Associated With Monoclonal Gammopathies

Monoclonal gammopathies of clinical significance (MGCS): In pursuit of optimal treatment

Monoclonal gammopathy of clinical significance (MGCS) represents a new clinical entity referring to a myriad of pathological conditions associated with the monoclonal gammopathy of undetermined significance (MGUS). The establishment of MGCS expands our current understanding of the pathophysiology of a range of diseases, in which the M protein is often found. Aside from the kidney, the three main organ systems most affected by monoclonal gammopathy include the peripheral nervous system, skin, and eye. The optimal management of these MGUS-related conditions is not known yet due to the paucity of clinical data, the rarity of some syndromes, and limited awareness among healthcare professionals. Currently, two main treatment approaches exist. The first one resembles the now-established therapeutic strategy for monoclonal gammopathy of renal significance (MGRS), in which chemotherapy with anti-myeloma agents is used to target clonal lesion that is thought to be the culprit of the complex clinical presentation. The second approach includes various systemic immunomodulatory or immunosuppressive options, including intravenous immunoglobulins, corticosteroids, or biological agents. Although some conditions of the MGCS spectrum can be effectively managed with therapies aiming at the etiology or pathogenesis of the disease, evidence regarding other pathologies is severely limited to individual patient data from case reports or series. Future research should pursue filling the gap in knowledge and finding the optimal treatment for this novel clinical category.

Systemic therapy of necrobiotic xanthogranuloma: a systematic review

BACKGROUND

Even though a plethora of systemic therapies have been proposed for necrobiotic xanthogranuloma (NXG), there is no systematic review on this topic in literature.

OBJECTIVE

To review all existing literature on the systemic therapy of NXG in order to identify the most effective therapies.

METHODS

All reported papers in the literature were screened for systemic treatments of NXG. Papers without proper description of the therapies, papers describing topical therapy, and articles without assessment of effectiveness were excluded. Subsequently, we analyzed 79 papers and a total of 175 cases.

RESULTS

The most effective treatments for NXG are intravenous immunoglobulins (IVIG), corticosteroids, and combination therapies including corticosteroids.

CONCLUSIONS

Corticosteroids and IVIG should therefore be considered first-line treatments in patients with NXG.

First case report of pre-mortem biopsy-proven kidney involvement by necrobiotic xanthogranuloma with monoclonal gammopathy

Necrobiotic xanthogranuloma (NXG) is a rare non-Langerhans cell histiocytosis with characteristic cutaneous features and rare visceral involvement. More than 80% of individuals with this disease have a detectable paraprotein but the precise pathogenesis remains obscure. A 68-year-old man with known cutaneous necrobiotic xanthogranuloma presented with acute kidney injury and imaging suggestive of bilateral perinephric infiltration. Renal biopsy showed a prominent histiocytic infiltration of renal capsule and cortex with necrobiosis and characteristic 'Touton-type' giant cells suggestive of necrobiotic xanthogranuloma involvement. Kidney function returned to normal and cutaneous lesions improved with a combination of corticosteroid, chlorambucil and rituximab. This case represents only the second reported incidence of kidney involvement by necrobiotic xanthogranuloma and the first with acute kidney injury and pre-mortem histopathology. This report adds to a small body of literature on the diagnosis and management of visceral involvement by this rare disease.

Types of M protein and clinicopathological profiles in patients with monoclonal gammopathy of renal significance

BACKGROUND

The development of renal disease in patients with monoclonal gammopathy of renal significance (MGRS) depends on the pathogenicity of the secreted monoclonal protein (M protein). However, the correlation between the types of M proteins and clinical and renal pathological features is still unclear.

METHODS

A total of 148 patients with detectable serum M protein and biopsy-proven MGRS were recruited. The patients were categorized according to the heavy and light chain types of M protein in the serum.

RESULTS

Among 148 patients, the most common M protein was IgGλ, followed by IgAλ and IgGκ. According to the type of heavy chain, patients with IgM-MGRS were more likely to have renal dysfunction, anemia and hypocomplementemia than patients with IgG-MGRS and IgA-MGRS. The λ light chain was predominant in patients with IgG-MGRS and IgA-MGRS, whereas the κ light chain was predominant in patients with IgM-MGRS. The most common renal lesion was amyloidosis in patients with IgG-MGRS and IgA-MGRS, while it was cryoglobulinemic glomerulonephritis in patients with IgM-MGRS. According to the type of light chain, patients with κ light chain were more likely to be male and to have renal dysfunction, anemia and hypocomplementemia than those with λ light chain. The types of heavy chain and light chain of M protein were not associated with patient or renal survival.

CONCLUSION

The clinicopathological features were distinct in patients with different types of M protein. Integration of the types of M protein and renal pathologic findings may shed light on individual management of patients with MGRS.

A Multicenter Cross-Sectional Study and Systematic Review of Necrobiotic Xanthogranuloma With Proposed Diagnostic Criteria

Importance

Necrobiotic xanthogranuloma (NXG) is a non-Langerhans cell histiocytosis classically associated with paraproteinemia attributable to plasma-cell dyscrasias or lymphoproliferative disorders. Despite the morbidity of NXG, the literature is limited to case reports and small studies, and diagnostic criteria are lacking.

Objective

To evaluate the characteristics of NXG and propose diagnostic criteria.

Design, Setting, and Participants

This multicenter cross-sectional study was conducted at tertiary academic referral centers and followed by a systematic review and a consensus exercise. The multicenter cohort included patients with NXG diagnosed at the Brigham and Women's and Massachusetts General Hospitals (2000-2018), the University of Iowa Hospitals and Clinics (2000-2018), and the University of Pennsylvania Health System (2008-2018). The systematic review was conducted in 2018 and included patients with NXG identified in the Cochrane, Ovid EMBASE, PubMed, and Web of Science databases. The consensus exercise was conducted by 8 board-certified dermatologists to identify diagnostic criteria.

Main Outcomes and Measures

Demographic factors, comorbidities, clinical features, and treatment response.

Results

Of 235 included patients with NXG (34 from the multicenter cohort and 201 from the systematic review results), the mean (SD) age at presentation was 61.6 (14.2) years; 147 (62.6%) were female. Paraproteinemia was detected in 193 patients (82.1%), most often IgG-κ (117 patients [50.0%]). A malignant condition was detected in 59 patients (25.1%), most often multiple myeloma (33 patients [14.0%]). The overall rate of paraproteinemia and/or a malignant condition was 83.8% (197 patients). In the multicenter cohort, evolution of paraproteinemia into multiple myeloma was observed up to 5.7 years (median [range], 2.4 [0.1-5.7] years) after NXG presentation. Cutaneous lesions consisted of papules, plaques, and/or nodules, typically yellow or orange in color (113 of 187 [60.4%]) with a periorbital distribution (130 of 219 [59.3%]). The eye was the leading site of extracutaneous involvement (34 of 235 [14.5%]). In the multicenter cohort, intravenous immunoglobulin had the best treatment response rate (9 of 9 patients [100%]), followed by antimalarial drugs (4 of 5 patients [80%]), intralesional triamcinolone (6 of 8 patients [75%]), surgery (3 of 4 patients [75%]), chemotherapy (8 of 12 patients [67%]), and lenalidomide or thalidomide (5 of 8 patients [63%]). The consensus exercise yielded 2 major criteria, which were (1) clinical and (2) histopathological features consistent with NXG, and 2 minor criteria, consisting of (1) paraproteinemia, plasma-cell dyscrasia, and/or other associated lymphoproliferative disorder and (2) periorbital distribution of cutaneous lesions. In the absence of foreign body, infection, or another identifiable cause, fulfillment of both major and at least 1 minor criterion were proposed to establish the diagnosis of NXG.

Conclusions and Relevance

Necrobiotic xanthogranuloma is a multisystem disorder associated with paraproteinemia and malignant conditions. The proposed diagnostic criteria may advance clinical research and should be validated.

Necrobiotic xanthogranuloma associated with smoldering multiple myeloma: satisfactory response to cyclophosphamide, dexamethasone, and thalidomide

Necrobiotic xanthogranuloma is a rare chronic condition, belonging to the group C non-Langerhans cell histiocytoses, which is relevant due to the possibility of extracutaneous involvement and association with systemic diseases, particularly hematologic malignancies. The case reported here was only diagnosed after nine years of evolution and was associated with plasma cell dyscrasia. After treatment with cyclophosphamide, dexamethasone, and thalidomide, there was a reduction of cutaneous lesions and serum levels of monoclonal protein.

Monoclonal gammopathy of clinical significance: a novel concept with therapeutic implications

Monoclonal gammopathy is a common condition, particularly in the elderly. It can indicate symptomatic multiple myeloma or another overt malignant lymphoid disorder requiring immediate chemotherapy. More frequently, it results from a small and/or quiescent secreting B-cell clone, is completely asymptomatic, and requires regular monitoring only, defining a monoclonal gammopathy of unknown significance (MGUS). Sometimes, although quiescent and not requiring any treatment per se, the clone is associated with potentially severe organ damage due to the toxicity of the monoclonal immunoglobulin or to other mechanisms. The latter situation is increasingly observed but still poorly recognized and frequently undertreated, although it often requires rapid specific intervention to preserve involved organ function. To improve early recognition and management of these small B-cell clone–related disorders, we propose to introduce the concept of monoclonal gammopathy of clinical significance (MGCS). This report identifies the spectrum of MGCSs that are classified according to mechanisms of tissue injury. It highlights the diversity of these disorders for which diagnosis and treatment are often challenging in clinical practice and require a multidisciplinary approach. Principles of management, including main diagnostic and therapeutic procedures, are also described. Importantly, efficient control of the underlying B-cell clone usually results in organ improvement. Currently, it relies mainly on chemotherapy and other anti–B-cell/plasma cell agents, which should aim at rapidly producing the best hematological response.

How I manage monoclonal gammopathy of undetermined significance

Monoclonal gammopathy of undetermined significance (MGUS) is, in many ways, a unique hematologic entity. Unlike most hematologic conditions in which the diagnosis is intentional and credited to hematologists, the discovery of MGUS is most often incidental and made by nonhematologists. MGUS is considered an obligate precursor to several lymphoplasmacytic malignancies, including immunoglobulin light-chain amyloidosis, multiple myeloma, and Waldenström macroglobulinemia. Therefore, long-term follow-up is generally recommended. Despite its high prevalence, there is surprisingly limited evidence to inform best clinical practice both at the time of diagnosis and during follow-up. We present 7 vignettes to illustrate common clinical management questions that arise during the course of MGUS. Where evidence is present, we provide a concise summary of the literature and clear recommendations on management. Where evidence is lacking, we describe how we practice and provide a rationale for our approach. We also discuss the potential harms associated with MGUS diagnosis, a topic that is rarely, if ever, broached between patients and providers, or even considered in academic debate.

Management of Uveitis and Scleritis in Necrobiotic Xanthogranuloma

Necrobiotic xanthogranuloma (NXG) is a chronic, progressive non-Langerhans histiocytic granulomatous disease. While case reports describing periorbital involvement of NXG are frequent, only a few case reports describing ocular involvement, such as scleritis and uveitis, exist. Herein, we present a case presenting initially as bilateral anterior and posterior scleritis, as well as a chronic bilateral granulomatous panuveitis, and discuss the immunosuppressant options that should be considered for this disease with protean manifestations.