Pathogenesis and treatment of xanthomatosis associated with monoclonal gammopathy. Blood. 2011;118:3777-3784. [PMID: 21757618 DOI: 10.1182/blood-2011-05-356907]

Bilateral Adult-Onset Orbital Xanthogranuloma: A Case Report

Adult-onset xanthogranuloma (AOX) is one of the four rare syndromes collectively referred to as adult xanthogranulomatous disease (AXD). It primarily occurs in the orbit and ocular adnexa and displays distinctive histopathological features, characterized by the infiltration of non-Langerhans-derived foam-like histiocytes and Touton giant cells. The presence of diffuse yellow plaques on the eyelids serves as a highly indicative feature. In this report, we present a compelling case of bilateral periorbital AOX. Initially, the patient received a diagnosis of necrotizing xanthogranuloma (NBX) and underwent treatment with dapsone, which yielded a poor response. Subsequently, through repeated biopsy, immunoprotein electrophoresis, and high-throughput sequencing, the diagnosis was revised to AOX. Subsequently, the patient's treatment was modified to include oral hormone therapy, and no further progression of the periorbital plaque was observed. Notably, the patient's sister was diagnosed with xanthelasma palpebrarum (XP), suggesting a potential genetic association between AOX and XP. Unfortunately, the sister declined further histologic examination and genetic sequencing of her skin lesions, impeding the acquisition of additional evidence regarding the genetic link between these two disorders. Despite the divergent pathological features, pathogenesis, and clinical presentation of AOX and xanthelasma palbrarum, clinicians should remain cognizant of the plausible genetic correlation between these two conditions and pursue further investigations when feasible.

A long-term follow-up of necrobiotic xanthogranuloma with concomitant large-vessel vasculitis and heart failure with reduced ejection fraction: a case report

Background

Necrobiotic xanthogranuloma (NXG) is a non-Langerhans cell histiocytosis and multisystem disorder. Low level of HDL cholesterol associated with a systemic inflammatory profile, which may result from the interaction of monoclonal immunoglobulin and lipoproteins, is a characteristic feature. There is no evidence of NXG-associated large-vessel vasculitis, nor are there any established treatments, although chemotherapy for comorbid multiple myeloma is most often administered.

Case summary

We describe a case of a 53-year-old male with a first history of heart failure with impaired systolic function. He presented with orbital xanthomas and multiple subcutaneous nodules, and laboratory examination showed elevated levels of C-reactive protein, low HDL, and paraproteinemia. A constellation of these clinical features and pathological findings of skin biopsy led to the diagnosis of NXG. 18F-Fluorodeoxyglucose positron emission tomography (PET)/computed tomography (CT) confirmed increased uptake in the aorta and bilateral common carotid arteries. He began prednisolone treatment with reference to treatment for large-vessel vasculitis. After the treatment, C-reactive protein immediately decreased with markedly increased levels of apolipoprotein A1 (Apo-A1) and HDL. Systolic dysfunction was restored at 6-month follow-up. The patient has not experienced heart failure for 5 years after treatment, and the follow-up PET/CT demonstrated resolution of vascular inflammation.

Discussion

This is the first report of NXG-associated large-vessel vasculitis. Low-dose prednisolone may benefit for NXG-associated vasculitis and cardiomyopathy. HDL, Apo-A1, and C-reactive protein levels may be useful for monitoring the activity of NXG, and PET/CT was a valuable diagnostic tool for NXG-associated vasculitis.

Digital Patient Education on Xanthelasma Palpebrarum: A Content Analysis

Patient education has been transformed using digital media and online repositories which disseminate information with greater efficiency. In dermatology, this transformation has allowed for patients to gain education on common cutaneous conditions and improve health literacy. Xanthelasma palpebrarum is one of the most common cutaneous conditions, yet there is a poor understanding of how digital materials affect health literacy on this condition. Our study aimed to address this paucity of literature utilizing Brief DISCERN, Rothwell's Classification of Questions, and six readability calculations. The findings of this study indicate a poor-quality profile (Brief DISCERN < 16) regarding digital materials and readability scores which do not meet grade-level recommendations in the United States. This indicates a need to improve the current body of educational materials used by clinicians for diagnosing and managing xanthelasma palpebrarum.

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.

Monoclonal gammopathy of clinical significance: what the rheumatologist needs to know

Monoclonal proteins can provide important information on the diagnosis of several non-malignant systemic inflammatory disorders. At low concentration, they most commonly represent monoclonal gammopathy of undetermined significance (MGUS), whereas high concentrations often signify plasma cell myeloma or B-cell lymphoma. However, several rare inflammatory conditions associated with variable concentrations of monoclonal proteins, systemic symptoms, and organ dysfunction also exist. These conditions are termed monoclonal gammopathies of clinical significance (MGCS). Patients with MGCS might present to rheumatologists with undiagnosed systemic inflammatory disorders and the monoclonal protein provides an important, underappreciated clue for diagnosis. In this Review, we provide an approach to distinguishing MGCS from MGUS and lymphoid neoplasms, focusing on four rare MGCS that rheumatologists must recognise: scleromyxedema, Schnitzler's syndrome, idiopathic systemic capillary leak syndrome (also known as Clarkson's disease), and telangiectasias, elevated erythropoietin and erythrocytosis, monoclonal gammopathy, perinephric fluid collections, and intrapulmonary shunting (known as TEMPI) syndrome.

Diagnosis and management of monoclonal gammopathy of clinical significance

The term "monoclonal gammopathy of clinical significance" (MGCS) refers to any plasma cell or B-cell clonal disorder that does not meet the current criteria for malignant disorders but produces a monoclonal protein that directly or indirectly results in organ damage. The most commonly affected organs are the kidneys, nerves, and skin. This review summarizes the current classification of MGCS and its diagnostic and treatment approaches.

Cutaneous manifestations of monoclonal gammopathy

Monoclonal gammopathy associated with dermatological manifestations are a well-recognized complication. These skin disorders can be associated with infiltration and proliferation of a malignant plasma cells or by a deposition of the monoclonal immunoglobulin in a nonmalignant monoclonal gammopathy. These disorders include POEMS syndrome, light chain amyloidosis, Schnitzler syndrome, scleromyxedema and TEMPI syndrome. This article provides a review of clinical manifestations, diagnostics criteria, natural evolution, pathogenesis, and treatment of these cutaneous manifestations.

Monoclonal gammopathies of clinical significance

"Monoclonal gammopathy of clinical significance" (MGCS) is the term used to describe nonmalignant monoclonal gammopathies causing important disease. MGCS is the differential diagnosis for any patient presenting with what appears to be a monoclonal gammopathy of undetermined significance but is also experiencing other unexplained symptoms. Broadly, these conditions can be separated into symptoms and signs referable to the nerves, the kidneys, and the skin. The first step in making these diagnoses is to consider them. With a particular condition in mind, the next step is to order those tests that can help confirm or dismiss a particular diagnosis. Nearly all of the renal and dermatologic conditions are diagnosed by renal and skin biopsies, respectively. The importance of a highly competent renal pathologist and dermatopathologist cannot be underestimated. Biopsy is less specific for the neuropathic conditions. Because several of the MGCSs are syndromes, recognizing other manifestations is also key. Treatment recommendations for many of these conditions are anecdotal because of their rarity, but for several of the conditions, IV immunoglobulin, rituximab, and plasma cell-directed therapy are the best options.

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.

Intralesional injection of bleomycin in the treatment of xanthelasma palpebrarum: A clinical study

BACKGROUND

Xanthelasma palpebrarum (XP) is the most common type of cutaneous xanthoma and has been treated with intralesional injection of pingyangmycin effectively. However, bleomycin, which has the same effect in antitumor activity as pingyangmycin, has not been applied in the treatment of XP.

AIMS

To explore and assess the treatment of xanthelasma by intralesional injection of bleomycin, which has been widely used as an antitumor antibiotic, for the replacement of pingyangmycin.

METHODS

Intralesional injection of different concentrations of bleomycin was administered to 44 xanthelasma lesions of 24 patients who have never been treated before, divided into two groups according to age. Photographs were taken and analyzed to assess the therapeutic efficiency. Patients were then followed up for 6-24 months.

RESULTS

All the lesions resolved after 1 month of treatment with the intralesional injection of different concentrations of bleomycin. There was no significant difference observed between the two groups. No severe complications had occurred.

CONCLUSION

The treatment of XP with intralesional injection of bleomycin is minimally invasive, safe, and effective. Consequently, it also has good cosmetic outcome with no adverse effects.

Necrobiotic Xanthogranuloma Coexists with Diffuse Normolipidemic Plane Xanthoma and Multiple Myeloma

Necrobiotic xanthogranuloma (NXG), is a rare multisystem disease that manifests as cutaneous inflammatory lesions, and is commonly associated with lymphoproliferative disease. Diffuse normolipemic plane xanthoma (NX), is also a rare, acquired disease that is often associated with systemic diseases such as lymphoproliferative disease. Both of these diseases have been reported to be associated with monoclonal gammopathy (MG). However, there are few cases in which these diseases co-exist. A 78-year-old female, who had a known case of NX on the neck and axillary area, presented with an asymptomatic erythematous plaque on her left supraclavicular area. Histopathological examination showed lymphoid aggregates, necrobiotic areas, and granulomatous inflammation in the dermis. Numerous foreignbody and Touton type giant cells were noticed. Serum protein immunoelectrophoresis showed an IgG kappa type MG. Lipid profile of the patient was normal. Bone marrow examination showed plasma cell myeloma. Based on these histologic and laboratory results, we diagnosed this lesion as NXG coexisting with NX and multiple myeloma. She was started on treatment with bortezomib and melphalan for multiple myeloma, and high-dose systemic corticosteroid and triamcinolone intralesional injection for the skin lesion. After 3 months of treatment, the NXG skin lesion and MG improved.

The color of skin: yellow diseases of the skin, nails, and mucosa

The colors reflected from the skin are important indicators of dermatologic and systemic disorders. Incident light is subject to absorption by chromophores in the skin and scattering. Chromophores associated with yellow light reflection include the carotenoids and bilirubin. Various pathophysiologic mechanisms associated with these and other chromophores manifest with a yellow hue on examination. This review describes these mechanisms and the clinical features of yellow skin disorders by morphology. A brief summary of the differential diagnosis, laboratory investigations, and treatments are presented. Yellow skin disorders are a heterogenous group composed of abnormalities in keratin, elastic and connective tissue, lipid metabolism, and other states of metabolic, inflammatory, or organ dysfunction. Patients will present through different routes, and skin disease may precede or follow systemic disease. Dermatologists have an essential role in identifying those with malignant or systemic associations to ensure early diagnosis and treatment.

A case of intramuscular xanthelasma palpebrarum found during blepharoplasty

Xanthelasma palpebrarum is the most common cutaneous xanthoma found on the medial side of the eyelid. The typical lesion is usually a flat and yellowish plaque on the skin. However, we report on a unique case of intramuscular xanthoma found during blepharoplasty for the correction of ptosis. A 53-year-old male patient visited our department with a complaint of a ptotic eyelid. He was concerned about the cosmetic appearance and the uncomfortable feeling while opening his eyes, and wanted these problems to be solved. A yellowish plaque of about 0.3 × 0.3 cm in size was found in the orbicularis oculi muscle during the surgery. The lesion was excised and xanthelasma was confirmed with biopsy. We have found this specific case of xanthelasma palpebrarum in the only muscle. Therefore, a careful approach to clinical and histologic examination and imaging is required for patients with these lesions.

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.

Acquired low cholesterol: diagnosis and relevance to safety of low LDL therapeutic targets

PURPOSE OF REVIEW

Acquired hypocholesterolaemia occurs more commonly than inherited hypocholesterolaemia but has received little attention in the literature. In this review, we discuss the causes and underlying mechanisms of acquired hypocholesterolaemia and its relevance to safety of therapeutically induced decreased LDL cholesterol levels.

RECENT FINDINGS

Hypocholesterolaemia is increasingly identified as cholesterol testing becomes more widespread in the assessment of cardiovascular risk. Lower therapeutic targets for LDL cholesterol are also being achieved more regularly with the introduction of more intensive cholesterol-lowering regimens. Acquired hypocholesterolaemia may be the presenting feature of treatable diseases. Understanding its mechanisms may also provide new treatment approaches for neoplastic disease, such as breast cancer, and infections, such as tuberculosis.

SUMMARY

When hypocholesterolaemia is discovered, it is important to identify its cause. Further research into the pathogenesis of hypocholesterolaemia may provide new therapies for primary diseases underlying it.

Planar xanthomas secondary to post-transplantation cholangiopathy in a 16-month-old boy

Planar xanthomas in children represent rare dermatologic findings associated with abnormalities in lipid metabolism. While planar xanthomas in Alagille's syndrome have been well described in the literature, there have been no cases reported of eruptive xanthomas in pediatric liver transplant patients. Herein we report a case of a 16-month-old boy status post-liver transplantation who presents with planar xanthomas secondary to cholangiopathy. A brief review of xanthomas and the related literature is also provided.

Periorbital Necrobiotic Xanthogranuloma Successfully Treated with Intravenous Immunoglobulin

Background

Necrobiotic xanthogranuloma (NXG) is a rare non-Langerhans histiocytosis with cutaneous manifestations, most commonly of the periorbital skin, and is often associated with hematologic disorders such as monoclonal gammopathy. Treatment of NXG is notoriously difficult, and fraught with recurrence and progression.

Case Presentation

The authors describe a case of NXG with periorbital involvement in a patient with a complex autoimmune and hematologic medical history. The biopsy of this rare lesion prompted subsequent evaluation for an underlying disorder, which led to the diagnosis of multiple myeloma. Her NXG lesions demonstrated remarkable clinical improvement after treatment with intravenous immunoglobulin (IVIG).

Conclusions

This case demonstrates the ophthalmologist's critical role in the diagnosis and management of NXG, as early detection cannot only prevent ophthalmic consequences such as ocular perforation and blindness, but also prompt further investigation that may reveal an underlying disorder or systemic involvement, including hematologic malignancy as in this case. NXG has been effectively treated with IVIG in a handful of reported cases. To the author's knowledge, this is the third case of periorbital NXG successfully treated with IVIG, and the first in the ophthalmic literature.

Diffuse Normolipemic Plane Xanthoma (DNPX) of the Neck without Xanthelasma Palpebrum

Diffuse normolipemic plane xanthoma (DNPX) is an uncommon subtype of non-Langerhans histiocytosis. DNPX is characterised by xanthelasma palpebrarum, diffuse plane xanthoma of the head, neck, trunk, or extremities, and normal plasma lipid levels. The neck is the most common site. We report about a 62-year-old female Caucasian patient, who developed an asymptomatic fine wrinkling and loose skin on the neck and décolleté about three years ago. The skin colour became yellowish. Xanthelasma was absent. Histopathology of a skin biopsy confirmed the diagnosis of DNPX. The patient had a medical history of chronic myeloblastic leukaemia. No other laboratory abnormalities were found. Laser treatment was offered but opposed by the patient.

Pleomorphic cutaneous xanthomas disclosing homozygous familial hypercholesterolemia

Homoxygous Familial Hypercholesterolemia is characterized by a presence of several types of cutaneous xanthomas with an abnormal lipid profile. Some of these could be pathognomonic. Although these could be initially interpreted as isolated and localized benign disorders and offered surgical treatment, it has become increasingly clear that they could be a part of a systemic pathology. Here we describe a case of this rare disorder in a 19 years old non-obese young man who presented multiple, intertriginous, tuberous and tendinous xanthomas and had an associated abnormal lipid profile with elevated low-density lipoprotein cholesterol levels. A detailed history with clinical assessment in the differential diagnosis and laboratory investigations led to a precise diagnosis.

Clinical presentation and outcomes of patients with type 1 monoclonal cryoglobulinemia

We describe a series of 102 patients diagnosed from January 1, 1990 to December 31, 2015 with Type 1 monoclonal cryoglobulinemia (MoC). Symptoms were seen in 89 (87%) patients, including: cutaneous symptoms in 64 (63%) patients, with purpura (n = 43, 42%) and ulcers/gangrene (n = 35, 34%) being most common; neurological findings in 33 (32%) patients, most frequently sensory neuropathy (n = 24, 24%); vasomotor symptoms, mainly Raynaud's phenomenon in 25 (25%); arthralgias in 24 (24%); and renal manifestations, primarily glomerulonephritis in 14 (14%) patients. An underlying lymphoproliferative disorder was identified in 94 (92%) subjects; MGUS-39, myeloma-20, lymphoplasmacytic lymphoma-21 and others-14. Treatment was initiated in 73 (72%) patients, primarily for cryoglobulinemia-related symptoms in 57. Treatment regimens consisted of: steroids ± alkylating agents in 29 (40%), novel myeloma therapies in 16 (22%), rituximab with alkylating agents in 12 (16%) and rituximab ± steroids in 11 (15%) patients; 22 patients received plasmapheresis. Six patients underwent autologous stem cell transplant. Cryocrit at treatment initiation, change in cryocrit and time to nadir cryocrit were predictive of symptom improvement. Treatment directed toward the underlying clonal disorder resulted in improvement (n = 47) or stabilization (n = 16) of symptoms in the majority of patients and disappearance of cryoglobulin in over one-half.

Comparative Study of Clinical, Pathological, Radiological, and Genetic Features of Patients With Adult Ocular Adnexal Xanthogranulomatous Disease, Erdheim-Chester Disease, and IgG4-Related Disease of the Orbit/Ocular Adnexa

PURPOSE

To compare and contrast the clinical, radiologic, pathologic, and genetic features of patients with ocular adnexal IgG4-related disease (IgG4-RD) and patients with adult ocular adnexal xanthogranulomatous disease (XG).

METHODS

This retrospective review study identified patients with histological evidence of either disease from records of the pathology department of our hospital from 1996 to 2014. Clinical, imaging, and a variety of histopathologic features were collected for 23 patients with IgG4-RD and 13 patients with XG. Next generation sequencing with a 50-gene cancer screening panel was performed on biopsy tissues from 10 patients in each group.

RESULTS

Statistical differences between the 2 groups include eyelid (67%; p = 0.0002) and anterior orbital (75%; p = 0.0352) predilection for XG except for Erdheim-Chester disease subgroup which was more posterior and diffuse. Eyelid involvement was rare (4%) for IgG4-RD. Involvement of orbital nerves was seen in 30% of IgG4-RD and 0% in XG (p = 0.0695). Five patients with IgG4-RD developed malignancy (4 lymphoma, 1 leiomyosarcoma), but none of XG patients. Discriminating pathological features were the presence of any IgG4+ plasma cells (p = 0.0121) and the ratio of IgG4+/IgG+ plasma cells (p =0.0294) for IgG4-RD. Five of 12 (42%) patients with XG had sufficient numbers of IgG4+ plasma cells/high power field to fulfill published diagnostic criteria for IgG4-RD, and 5 (42%) had a ratio of IgG4+/IgG+ plasma cells over 40%, but the numbers overall were less than seen in the IgG4-RD patients. The only genetic difference between the 2 groups was that BRAF V600E mutation was found in 1 of the 2 Erdheim-Chester disease patients, which form a subgroup of XG.

CONCLUSIONS

IgG4-RD and XG share clinical, imaging, and histopathological features including IgG4+ plasma cells. Significant differences were the eyelid involvement in XG, orbital nerve involvement, and an elevated IgG4+/IgG+ ratio in IgG4-RD and the only genetic abnormality found was BRAF V600E mutation in the Erdheim-Chester disease subgroup of XG.

Adult Xanthogranulomatous Disease of the Orbit: Clinical Presentations, Evaluation, and Management

Adult xanthogranulomatous disease of the orbit refers to a heterogeneous group of clinical syndromes with differing degrees of systemic involvement and distinct prognoses. The different syndromes all present clinically with progressively enlarging, yellowish lesions of the orbit. Histologically, the lesions are characterized by an inflammatory infiltrate of foam cells and Touton-type multinucleated giant cells. The xanthomatized histiocytes are CD68⁺, S100^-, and CD1a^-. There are 4 clinical forms of xanthogranulomatous disease of the orbit: adult xanthogranulomatous disease of the orbit, adult onset asthma and periocular xanthogranuloma, necrobiotic xanthogranuloma, and Erdheim-Chester disease. The treatment of local lesions are treated with systemic corticosteroids and other immunosuppressors. Vemurafenib, tocilizumab, and sirolimus have shown promising results in systemic disease.

Necrobiotic Xanthogranuloma in a Patient with Multiple Myeloma

An 82-year-old woman presented with a 9-month history of multiple, well-defined skin lesions on her neck and upper chest, progressively increasing in size. Histological examination of a skin biopsy showed a regular epidermis. In the dermis, granulomatous changes with central necrobiosis were found which extended focally into the subcutaneous fat. The necrobiotic areas were surrounded by Touton cells and foreign-body giant cells. Laboratory analysis revealed leucopenia. Serum electrophoresis and immunofixation disclosed the presence of an IgG-λ paraprotein. Bone marrow aspiration cytology showed 20% plasmatic cells. The skeletal X-ray revealed frontal and occipital osteolytic skull lesions as well as pubic osteolysis. Urinalysis was unremarkable without proteinuria. Based on the clinical, laboratory, and histological findings, necrobiotic xanthogranuloma in association with multiple myeloma was diagnosed. The patient was treated with bortezomib combined with oral dexamethasone. Follow-up at week 13 revealed the complete disappearance of the IgG paraproteinemia. However, the skin lesions remained unchanged. Therefore, bortezomib treatment was discontinued, and systemic corticosteroids were continued at a higher dosage. After the steroid treatment, the lesions markedly flattened.

Multiple large xanthomas: A case report

A 23-year-old male patient presented with multiple large masses in his elbows, buttocks, knees, Achilles tendons, feet, shoulders and hands. The large masses in the elbows and buttocks measured ~6×5×5 cm and ~7×5×4 cm, respectively. The patient presented with an elevated level of low-density lipoprotein cholesterol, and had been previously diagnosed with homozygous familial hypercholesterolemia (FH) and multiple xanthomas. Local surgical excisions were performed to remove the massive xanthomas from the elbows and buttocks, and histological analysis of the surgical specimens confirmed the previous diagnosis of homozygous FH (HoFH). The aim of the present study was to report a rare case of HoFH coinciding with multiple, large and widely-distributed xanthomas and to discuss the clinical characteristics, in order to provide a better understanding of xanthomas and FH.

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.

Monoclonal gammopathy: The good, the bad and the ugly

Monoclonal gammopathy of undetermined significance (MGUS) is a condition characterized by the presence of a monoclonal gammopathy (MG) in which the clonal mass has not reached a predefined state in which the condition is considered malignant. It is a precursor to conditions such as multiple myeloma or lymphoma at a rate of ~1%/year. Thus, from a hematologic standpoint, MGUS is a fairly benign condition. However, it is now recognized that organ damage resulting from just the MG without the need MM or lymphoma can occur. One of the most recognized is nephropathy secondary to monoclonal gammopathy of renal significance (MGRS). Other well-recognized conditions include neuropathies, oculopathies and dermopathies. Some conditions such as autoimmune diseases and coagulopathies are less common and recognized. Finally, systemic involvement of multiple organs is well described in several entities. In all of these conditions, the role of the MG is no longer insignificant. Thus, the term MGUS should be avoided when describing these entities.

[Xanthoma disseminatum with asymptomatic multisystem involvement]

BACKGROUND

Xanthogranulomas belong to non-Langerhans histiocytosis of the second group in the Histiocyte Society classification. They comprise a heterogeneous group of rare entities frequently involving cutaneous tropism. Xanthoma disseminatum belongs to this group of non-Langerhans histiocytosis. We report a case of xanthoma disseminatum (XD) in which localized skin and mucous impairment revealed multisystem involvement.

PATIENTS AND METHODS

A 28-year-old man presented with a two-year history of progressive yellow-orange and infiltrated xanthomatous papulonodular lesions of the face. Lesions of the oral mucosa and genital region were seen, with no functional repercussions. No ophthalmic or other complications were found. Histopathology showed a dense histiocytic infiltrate within the dermis with Touton giant cells, foamy multinucleated giant cells and inflammatory cells, without necrobiosis. Histiocytes were positive for CD68 but negative for CD1a. Gastric and lung involvement was seen and was confirmed at histology. Bone scintigraphy showed suspicious left ulnar hyperfixation suggesting bone involvement. No monoclonal gammopathy or diabetes insipidus was seen. Our patient was treated with corticosteroids 1mg/kg/day and thalidomide 100 mg/day. The outcome was marked by regression and exfiltration of the cutaneous lesions from the second week of treatment, with subsidence continuing at 3 months.

DISCUSSION

This case involves a very rare form of xanthoma disseminatum. The localized facial skin lesions revealed multifocal non-Langerhans histiocytosis that was in fact asymptomatic. The diagnosis of XD was based on clinical, histological and immunohistochemical criteria. Xanthoma disseminatum is a non-Langerhans histiocytic proliferation first described by Montgomery in 1938. This rare entity is characterized by skin and mucous membrane xanthomatosis in which the facial involvement is common, together with diabetes insipidus and normal lipid metabolism. The prognosis is determined by the presence of mucosal xanthomas and visceral involvement. Thus, all xanthogranulomas involving multiple lesions warrant screening for visceral involvement. Diagnosis of this entity can be difficult and is usually based on clinical and histopathological findings. In addition, treatment is complex and non-consensual.

Physiopathology of necrobiotic xanthogranuloma with monoclonal gammopathy

RATIONALE

Xanthomatosis associated with monoclonal gammopathy includes hyperlipidaemic xanthoma (HX), normolipidaemic xanthoma (NX) and necrobiotic xanthogranuloma (NXG). All three pathologies are characterized by skin or visceral lesions related to cholesterol accumulation, monoclonal immunoglobulin (MIg) and hypocomplementemia. The pathophysiology underlying NXG remains unknown although the involvement of MIg is suspected.

OBJECTIVE

To provide further insights into the pathophysiology of NXG, we evaluated the plasma lipid phenotype, mechanisms involved in cellular cholesterol accumulation and role of MIg in an analysis of blood and plasma markers of inflammation in 16 patients with xanthomatosis [NXG (n = 8) and NX (n = 8)] associated with monoclonal IgG relative to the relevant controls.

RESULTS

The lipid profile of patients with NXG was characterized by a low HDL-C phenotype and an abnormal distribution of HDL particles. Sera from patients with NXG induced cholesterol accumulation in human macrophages. This accumulation was due in part to a significant reduction in the HDL capacity to promote cholesterol efflux from macrophages, which was not found in the case of NX. The MIg of NXG and NX patients was tested positively by ELISA to recognize a large spectrum of lipoproteins. High plasma levels of pro-inflammatory cytokines (TNFα and IL-6), soluble cytokine receptors (sIL-6R, sTNFRI and sTNFRII), adhesion molecules (VCAM-1 and ICAM-1) and chemokines (MCP-1, IL-8 and MIP-1α) were observed in both patients with NXG and NX, revealing a specific xanthoma inflammatory signature which was inversely correlated with plasma levels of anti-inflammatory HDL. However, patients with NXG were distinguished by elevated levels of IL-15 and a marked increase in the rate of intermediate CD14++CD16+ monocytes.

CONCLUSION

This study revealed that NXG is characterized by impaired macrophage lipid homeostasis associated with a systemic inflammatory profile that may result from the interaction of MIg and lipoproteins.