Is oligometastatic disease an applicable and useful concept in haematologic malignancies? A narrative review of radiation therapy standards, modern techniques, and innovations

PURPOSE

Haematologic malignancies are particular in that they can generally be cured, even when distant metastases are present at diagnosis, unlike solid malignancies. Systemic treatments, including chemotherapy, targeted therapies, and immunotherapy, are the standard of care with excellent results. The considerable progress made in the management of these diseases in the last 20years has redefined the role of radiation therapy as minor in many clinical situations. We propose a literature review of data, showing that radiation therapy still has a role in curative, salvage, and palliative therapy situations.

MATERIAL AND METHODS

A document and literature search was carried out in the following databases: Medline and ClinicalTrial.gov, for the terms "radiotherapy", "haematologic malignancies", "Hodgkin lymphoma", "non-Hodgkin lymphoma", "CAR T cells", "multiple myeloma", "solitary plasmocytoma", "intensity-modulated radiotherapy", "extracranial stereotactic body radiation therapy" and "proton therapy references".

RESULTS

Haemopathological malignancies include a wide range of diseases and radiation therapy indications have been assessed over the past 20years. Currently, radiation therapy is indicated for localized disease (solitary plasmocytoma), as an adjuvant (Hodgkin lymphoma), in palliative settings, or after systemic treatment in relapsed patients (chimeric antigen receptor [CAR] T-cells) with a low recurrence burden, which can therefore be considered "oligorecurrence". Radiation therapy, through total body irradiation, has important indications, thanks to its immunomodulatory and/or myeloablative effects. Moreover, recent technological developments have made possible significant improvement in safety, contributing to radiation therapy being positioned in the treatment strategy of several indications.

CONCLUSIONS

Given the effectiveness of systemic treatments in hematologic malignancies, the oligometastasis stage is of little importance. A curative intent after local radiation therapy, even advanced stage, is possible, both with residual disease for advanced Hodgkin lymphoma, aggressive non-Hodgkin lymphoma, or solitary plasmocytoma, and even without evidence of disease after chemotherapy for Hodgkin or non-Hodgkin lymphoma. The role of new treatments, such as CAR T cells, allows us to consider radiation therapy after systemic treatment of relapsed diseases with low volume recurrence, which can be considered oligorecurrence.

Cytogenetic, Clinical, Hematologic, Demographic, Immunohistochemical, and Flow Cytometry Characteristics of Patients with Plasma Cell Neoplasm in Five Years: A First Report from Iran

Background

The aggregation of clonal plasma cells causes plasma cell neoplasms, which vary in severity and clinical outcomes. The present research focused on the epidemiological, clinical, immunologic, and cytogenetic characteristics of plasma cell neoplasms.

Methods

In this five-year retrospective cross-sectional study, demographic information such as age and sex, calcium elevation, renal insufficiency, anemia, and bone lesion (CRAB) characteristics, as well as laboratory data including bone marrow and peripheral blood film results, immunohistochemistry, flow cytometry, and cytogenetic study outcomes were collected at Shiraz University of Medical Sciences, Shiraz, Iran. The collected data were analyzed using SPSS Statistics software (version 20.0). Descriptive statistics were reported as numbers, percentages, and mean±SD.

Results

417 newly diagnosed plasma cell neoplasm patients were confirmed by bone marrow or other tissue biopsy tests. 279 patients were men (66.9%). The most prevalent age group was 60-64 years old (18.46%). Plasma cell myeloma (PCM) affected 355 (85.13%) patients, while monoclonal gammopathy of undetermined significance (MGUS) affected 6 (1.43%) patients. Solitary plasmacytoma was seen in 56 (13.42%) patients. At the time of diagnosis, 119 (33.52%) of 355 PCM patients were asymptomatic, whereas 236 (66.47%) patients had at least one CRAB symptom, 55 (15.49%) had two or more, and 14 (3.94%) had three or more. There were 7 (1.97%) cases of amyloidosis. Cytogenetic abnormalities were found in 51.28% (40/78) of the patients. Twenty-one individuals (52.5%) were hyperdiploid with multiple trisomy, while 19 (47.50%) were not.

Conclusion

When diagnosed, Iranian PCM patients might have more advanced disease. PCM was more prevalent in young adults, and hyperdiploid was the most common cytogenetic finding in this investigation.

Plasmacytoid urothelial carcinoma with duodenal metastasis-A rare tumor with unusual site of metastasis with grim outcome

Plasmacytoid urothelial carcinoma (PUC) is a newly recognized rare variant of urothelial carcinoma, which is now being increasingly diagnosed prospectively as well as by retrospective analysis of cases with a poor prognosis. Morphologically, these tumors simulate plasma cell neoplasms and pose a diagnostic challenge. Identifying this variant is essential in two aspects: therapy and prognosis. Here, we present a case who underwent multiple transurethral resection of bladder tumor (TURBT) procedures, each with a diagnosis of urothelial carcinoma, the plasmacytoid type which was confirmed on radical cystectomy, and after 1 year, the patient presented with duodenal metastasis. We discuss the morphological aspects of differentiating this tumor from variants of urothelial carcinoma and other tumors with a plasmacytoid appearance. Despite the recognition and aggressive treatment, the patient expires within 2 years of the first diagnosis of bladder carcinoma.

Epstein-Barr Virus-Positive Plasma Cell Neoplasms in Immunocompetent Patients: A Clinicopathological Study of 15 Cases from South China and Literature Review

Epstein-Barr virus (EBV)-positive plasma cell neoplasms (PCNs) in immunocompetent patients are a rare entity, the clinicopathological and prognostic features of which have not been well characterized. Fifteen cases of EBV-positive PCN arising in immunocompetent patients from south China were retrospectively analyzed, and an additional 44 cases from the literature were reviewed. The overall EBV-positive rate defined by EBV-encoded small RNAs (EBERs) in-situ hybridization of PCNs was 12.3% (15/122), and it was significantly higher in plasmacytoma (17.1%, 13/76) than in plasma cell myeloma/multiple myeloma (4.3%, 2/46; P=0.031). The age of the patients ranged from 17 to 79 years, with a median age of 56 years. There was a large preponderance of men, with a male-to-female ratio of 4:1. Solitary plasmacytoma of bone (23.8%, 5/21) had comparable EBV-encoded small RNAs-positive rates with extramedullary plasmacytoma arising in the upper respiratory tract (19.5%, 8/41; P=0.949). Anaplastic and classic cytologic appearance was observed in 61.5% (8/13) and 38.5% (5/13) of EBV-positive plasmacytomas, respectively. Cases with an anaplastic cytologic appearance had a significantly higher Ki-67 proliferation index than those with a classic cytologic appearance (median: 55% vs. 10%, P=0.001). In the combined cohorts, anaplastic/plasmablastic cytologic appearance was significantly more common in extramedullary plasmacytoma arising in the upper respiratory tract (72.0%, 18/25) than outside the upper respiratory tract (11.1%, 1/9; P=0.006). Among the 59 cases of EBV-positive PCN, survival data of 34 cases were available for analysis, including 30 cases of plasmacytoma and 4 cases of plasma cell myeloma/multiple myeloma. There was no statistically significant difference in overall survival between patients with EBV-positive plasmacytomas in the combined cohorts and EBV-negative plasmacytomas in the present cohort. The prevalence of EBV in PCN in immunocompetent patients varies according to histologic subtype and tumor location. Compared with EBV-negative cases, EBV-positive plasmacytomas tend to have an anaplastic/plasmablastic cytologic appearance. No significant impact of EBV infection on clinical outcomes is observed in the limited number of reported cases.

A prognostic nomogram and risk classification system of elderly patients with extraosseous plasmacytoma: a SEER database analysis

BACKGROUND

The survival trends and prognostic factors of patients with extraosseous plasmacytoma (EOP) or extramedullary plasmacytoma (EMP) have not been reported in recent years. The objective of this study was to develop a novel nomogram and risk stratification system for predicting the overall survival (OS) of elderly patients with EOP based on the Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

The demographic characteristics of 900 patients aged 60 years and above, diagnosed with EOP between 2000 and 2019, were extracted from the SEER database. The patient population was randomly divided into a training cohort and an internal validation cohort in a ratio of 7:3. Univariate and multivariate Cox regression analyses were conducted to identify independent predictors of prognosis in elderly EOP patients, followed by developing a nomogram for prognostic assessment. The performance of the model was evaluated through receiver-operating characteristic (ROC) curves, C-index, calibration curves for calibration accuracy assessment, and decision curve analysis (DCA) to assess its clinical utility. All elderly EOP patients were stratified into three risk subgroups by cutoff value utilizing X-tile software based on their total OS scores for comparative analysis purposes. Kaplan-Meier (K-M) survival curve analysis was employed to validate any observed differences in OS among these three risk groups.

RESULTS

Six factors including age, year of diagnosis, marital status, primary site, surgery, and prior tumor history were identified to be independently predictive of the OS of elderly patients with EOP, and these predictors were included in the construction of the nomogram. The 1-, 3-, and 5-year area under the curves (AUCs) for OS were 0.717, 0.754, and 0.734 in the training cohort and 0.740, 0.730, and 0.765 in the validation cohort, respectively. The C-index values in the two cohorts were 0.695 and 0.690. The calibration curves and DCA exhibit commendable consistency and validity, respectively, thereby demonstrating their robust performance. The training set was stratified into low-, medium-, and high-risk subgroups based on the optimal cutoff points (167.8 and 264.8) identified. The K-M curve and cumulative risk curve exhibited statistically significant disparities in survival rates among the groups.

CONCLUSIONS

We developed a nomogram and risk classification system, which can serve as an intuitive and effective tool for clinicians to enhance the prediction of OS in elderly EOP patients, thereby facilitating the formulation of more rational and personalized treatment strategies.

Detection of serum M-protein in acetonitrile precipitates by MALDI-TOF mass spectrometry: A novel, low-cost methodology

BACKGROUND

Several studies have demonstrated the analytical sensitivity of MALDI-TOF mass spectrometry (MALDI-TOF MS) by immunoenrichment for M-protein analysis. We report the results of a novel, low-cost, reagent-based extraction process using acetonitrile (ACN) precipitation to enrich for κ and λ light chains which can be analysed by MALDI-TOF MS.

METHODS

Institutional Ethics committee approval was obtained. Serum samples from patients with monoclonal gammopathy of undetermined significance (MGUS), multiple myeloma (MM), plasmacytoma, AL amyloidosis and Waldenström macroglobulinemia (WM) underwent ACN precipitation. The images obtained were overlaid on apparently healthy donor serum samples to confirm the presence of M-protein. A sample was considered positive for M-protein if there was a sharp or broad peak within the κ or λ mass/charge (m/z) range: m/z- [M + 2H]2+: 11,550-12,300 Da and λ m/z- [M + 2H]2+: 11,100-11,500 Da. Images were acquired at a m/z range of 10,000-29,000 Da. Corresponding serum protein electrophoresis (SPEP), serum immunofixation electrophoresis (IFE) and serum free light chain (sFLC) assay by nephelometry were performed for all the samples.

RESULTS

Two-hundred-and-two serum samples were included in the study: MM- 184 (91%); AL amyloidosis- 2 (1%); plasmacytoma- 8 (4%); MGUS- 6 (3%) and WM- 2 (1%). All the SPEP positive samples were identified by MALDI-TOF MS. Out of 179 samples positive for M-protein by IFE, MALDI-TOF MS was positive in 176 samples (98%). Compared to IFE, the sensitivity and specificity of M-protein identification by MALDI-TOF MS were 98.3% and 52.2%, respectively.

CONCLUSIONS

This study demonstrates the feasibility of qualitatively identifying M-protein without the need for antibody-based immunoenrichment, making the technique cost-effective.

Incidental Finding of Multiple Synchronous Neoplasms in Explanted Liver After Transplantation: A Case Report

Liver transplantation is the only potentially curative treatment for patients with end-stage liver disease. After the procedure, histopathologic analysis of the liver explant may reveal neoplasms that were not previously diagnosed in preoperative imaging examinations. This incidental finding of primary liver neoplasms in the explant is not an uncommon situation in liver transplant, and hepatocarcinomas and cholangiocarcinomas are the types of tumors most frequently encountered in this scenario. These are the most common primary neoplasms of the liver, and liver transplantation is often a curative treatment for these types of tumors when they are in their earlier stages. In contrast, liver plasmacytoma is a rare type of plasma cell neoplasm, consisting of a single mass of monoclonal plasma cells, which is treated primarily by radiotherapy and is seldom encountered in the setting of liver transplant. We report the case of a patient who underwent liver transplantation for the treatment of cryptogenic cirrhosis, with no preoperative diagnosis of liver tumors. Analysis of the liver explant revealed the presence of three synchronous neoplasms with different histologic origins: a 27-mm hepatocellular carcinoma, a 17-mm intrahepatic cholangiocarcinoma, and a 25-mm solitary hepatic plasmacytoma. The patient received no further adjuvant treatment and remained well and with no signs of disease recurrence over an observation period of 44 months. We found no previous report in the literature of the synchronous presence of these three types of liver neoplasms.

Rare Distribution of Sclerotic Bony Lesions in Multiple Myeloma: A Case Report

ABSTRACT

A 66-year-old man was referred to our hospital due to a newly discovered left chest wall mass, which was diagnosed as plasmacytoma on biopsy. The patient underwent 18F-FDG PET/CT scanning before treatment. PET imaging revealed intense FDG signal in osseous lesions, and the CT showed most of the lesions were osteoblastic. The osseous lesions were predominantly localized to the humerus, femur, tibia, and phalanx of toe.

Extramedullary disease in multiple myeloma: a systematic literature review

Extramedullary involvement (or extramedullary disease, EMD) represents an aggressive form of multiple myeloma (MM), characterized by the ability of a clone and/or subclone to thrive and grow independent of the bone marrow microenvironment. Several different definitions of EMD have been used in the published literature. We advocate that true EMD is restricted to soft-tissue plasmacytomas that arise due to hematogenous spread and have no contact with bony structures. Typical sites of EMD vary according to the phase of MM. At diagnosis, EMD is typically found in skin and soft tissues; at relapse, typical sites involved include liver, kidneys, lymph nodes, central nervous system (CNS), breast, pleura, and pericardium. The reported incidence of EMD varies considerably, and differences in diagnostic approach between studies are likely to contribute to this variability. In patients with newly diagnosed MM, the reported incidence ranges from 0.5% to 4.8%, while in relapsed/refractory MM the reported incidence is 3.4 to 14%. Available data demonstrate that the prognosis is poor, and considerably worse than for MM without soft-tissue plasmacytomas. Among patients with plasmacytomas, those with EMD have poorer outcomes than those with paraskeletal involvement. CNS involvement is rare, but prognosis is even more dismal than for EMD in other locations, particularly if there is leptomeningeal involvement. Available data on treatment outcomes for EMD are derived almost entirely from retrospective studies. Some agents and combinations have shown a degree of efficacy but, as would be expected, this is less than in MM patients with no extramedullary involvement. The paucity of prospective studies makes it difficult to justify strong recommendations for any treatment approach. Prospective data from patients with clearly defined EMD are important for the optimal evaluation of treatment outcomes.

[Detection of paraprotein in plasma cell tumors]

Paraprotein is a laboratory biomarker of plasma cell tumors and other lymphoproliferative diseases. Its determination is necessary for diagnosing, monitoring and assessment of therapy effectiveness. The lecture presents the main methods of qualitative and quantative analysis of monoclonal proteins: gel electrophoresis, capillary electrophoresis, immunofixation and nephelometry features, possibilities and limitations are reviewed. The main sources of errors and artifacts during these studies are considered. Also the difficulties in the diagnosis and interpretation of the results of serum and urine tests are highlighted.

Extramedullary relapse in a patient with multiple myeloma: a rare cause of gastrointestinal perforation and massive bleeding

Multiple myeloma (MM) patients live longer due to more effective treatment, and we now see previously uncommon manifestations of MM, like extramedullary disease. We present a case of a 74-year-old man known with MM that relapsed with extramedullary manifestations at different locations. One of them as a gastric plasmacytoma (GP). He was successfully treated with chemoradiotherapy (Daratumumab, Bortezomib and Dexamethasone), which resulted in clinical response for 8 months, confirmed by biopsy and histopathology. Perforation of the GP occurred, and he underwent partial gastrectomy (Billroth II gastrojejunostomy). The patient's disease progressed again 5 months after surgery, and he did not want any additional treatment. He accepted palliative care and died 10 months after the operation. A lack of knowledge about the characteristics and treatment of extramedullary MM exists, and prospective studies to investigate incidence, prognosis and treatment for extramedullary MM are needed for improving the poor prognosis of this manifestation.

Cutaneous involvement of multiple myeloma

Cutaneous multiple myeloma (MM) is a rare disease. It can be primary or secondary in origin. The secondary type is further classified into specific and nonspecific types. The specific type is uncommon and is known as a secondary cutaneous plasmacytoma. We report a case of secondary cutaneous plasmacytoma in a 58-year-old man who had a history of plasma cell tumour of the lung and multiple myeloma. He achieved complete remission after the completion of chemotherapy and autologous stem cell transplant (ASCT). However, five months later, he developed multiple erythematous nodules on the whole body. Skin biopsy revealed diffuse neoplastic cells infiltrate in the reticular dermis with sparing of the upper papillary dermis and epidermis. The neoplastic cells were monotonous and homogenous with variable degrees of cytological atypia. Occasional cells showed distinctive plasma cell features. Plasma cell lineage was confirmed with CD138. The cells were immunoreactive to Kappa. Ki-67 was greater than 90%. They were non-immunoreactive to CD45, CD3, CD20, CD79 alpha and CK AE1/AE3. The findings were consistent with secondary cutaneous plasmacytoma. Our case illustrates that MM may present with nonspecific dermatological manifestations. As specific cutaneous involvement of MM is very uncommon; a high degree of clinical suspicion, detailed medical history and histopathological examination are required to arrive at an early diagnosis.

[An illustrative case of the POEMS syndrome]

POEMS syndrome is a rare and invalidating entity characterized by polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and dermatoses. The diagnosis of this condition is often late and challenging due to the heterogeneity of clinical forms. The light chains secreted by the clonal plasmocytes cause overproduction of VEGF (Vascular Endothelial Growth Factor) responsible for the appearance of the clinical manifestations of POEMS. The diagnostic approach is based on different clinical and biological criteria. Patients with a solitary plasmacytoma are candidates for radiotherapy treatment. Patients with diffuse bone involvement or bone marrow infiltration are best treated by systemic drugs. The response to treatment may take several months before clinical and biological improvement. Early diagnosis and dedicated management limit the clinico-functional impact of POEMS.

Population Differentiation at the PVT1 Gene Locus: Implications for Prostate Cancer

Genetic variation in susceptibility to complex diseases, such as cancer, is well-established. Enrichment of disease associated alleles in specific populations could have implications for disease incidence and prevalence. Prostate cancer (PCa) is a disease with well-established higher incidence, prevalence, and worse outcomes among men of African ancestry in comparison to other populations. PCa is a multi-factorial, complex disease, but the exact mechanisms for its development and progression are unclear. The gene desert located on chromosome 8q24 is associated with aggressiveness of PCa. Interestingly, the non-protein coding gene locus Plasmacytoma Variant Translocation (PVT1) is present at chromosome 8q24 and is overexpressed in PCa. PVT1 gives rise to multiple transcripts with potentially different molecular and cellular functions. In an analysis of the PVT1 locus using data from the 1000 Genomes Project, we found the chromosomal region spanning PVT1 exons 4A and 4B to be highly differentiated between African and non-African populations. We further investigated levels of gene expression of PVT1 exons 4A and 4B and observed significant overexpression of these exons in PCa tissues relative to benign prostatic hyperplasia and to normal prostate tissues obtained from men of African ancestry. These results indicate that PVT1 exons 4A and 4B may have clinical implications in PCa a conclusion supported by the observation that transient and stable overexpression of PVT1 exons 4A and 4B significantly induce greater prostate epithelial cell migration and proliferation. We anticipate that further exploration of the role of PVT1 exons 4A and 4B may lead to the development of diagnostic, therapeutic, and other clinical applications in PCa.

Solitary Plasmocytoma of the Thyroid

A case of a man 53 years old with a solitary plasmocytoma of the thyroid is described. The nodule was 5 x 7 cm in size, and did not show uptake of I131. No sistemic clinical and laboratory signes were present. The patient was treated with total thyroidectomy and postoperative telecobaltotherapy. The case is the seven described in the medical literature.

Primary extramedullary esophageal plasmacytoma - a case report

Extramedullary plasmacytomas are very uncommon tumors, may occur commonly in the upper respiratory passages. These are rarely seen in the middle and lower gastrointestinal system and exceptional to originate in the esophagus. We present a novel case of a 65-year old man who presented with dysphagia and weight loss. After taking detailed clinical history and physical examination endoscopy was performed that showed an ulcero-proliferative lesion involving the lower third of esophagus. Histopathological examination revealed sheets of malignant plasma cells, some with prominent nucleoli. Immuno-histochemistry could not be done due to unavailability. A bone marrow biopsy was performed which was negative for involvement. This is a rare case of esophageal plasmacytoma diagnosed on endoscopy in a patient presenting with dysphagia.

[Clinical and cytogenetic characteristics of myeloma patients with overall survival less than 24 months]

OBJECTIVE

To explore the clinical characteristics of multiple myeloma (MM) patients with overall survival (OS) less than 24 months so as to stratify high-risk population.

METHODS

A total of 177 newly diagnosed MM inpatients were recruited from July 2008 to July 2012. Clinical parameters at diagnosis of international staging system (ISS), lactic dehydrogenase (LDH), serum calcium, extramedullary involvement and amyloidosis were collected and cytogenetic abnormalities were detected by fluorescence in situ hybridization (FISH). Response and death were recorded as endpoints. Otherwise the follow-up period was over 24 months.

RESULTS

And 73 patients dying within 24 months were classified into high-risk group while another 104 survivors for over 24 months into control group. Age and gender at baseline were comparable. However, OS of high-risk group was only 8 months while it was not attained during a median follow up of 38 months in control group (P < 0.001). The most common cause of death was progressive disease in both groups. The pre-treatment percentages of the following parameters were significantly higher in high-risk group, including ISS stage III (76.71% (56/73) vs 50.00% (52/104), P = 0.002), renal dysfunction (47.95% (35/73) vs 31.73% (33/104), P = 0.029), elevated LDH (20.55% (15/73) vs 7.69% (8/104), P = 0.015) and plasma cell leukemia (PCL, 5.48% (4/73) vs 0 (0/104), P = 0.016). Conversely, extramedullary involvement, plasmacytoma, amyloidosis and hypercalcemia were similar. Despite comparable chemotherapeutic regimens, the rate of deep response, including complete response (CR) and very good partial response (VGPR), was significant lower in high-risk group than that in control group (12.33% (9/73) vs 53.85% (56/104), P < 0.001). Overall response rates (ORR, i.e. CR+VGPR+ partial response (PR)) were markedly different (38.36% (28/73) vs 86.54% (90/104), P < 0.001). Univariate analysis of cytogenetic abnormalities indicated a higher proportion of 1q21 amplification in high-risk group (35.62% (26/73) vs 25.15% (22/104), P = 0.033). Multivariate Logistic regression revealed that ISS, LDH and primary response worse than PR independently affected early death (P = 0.046, 0.005, < 0.001).

CONCLUSIONS

MM patients with OS less than 24 months have distinct clinical characteristics. And aggressive regimens are needed to improve the outcomes of high-risk population.

Production and characterisation of monoclonal antibodies against 19-Nortestosterone

OBJECTIVE

To produce anti-19-Nortestosterone (NT) monoclonal antibodies and identify their immunological characteristics.

METHODS

Hybridomas were prepared by fusing NS0 mouse myeloma cells with splenocytes isolated from immunized BALB/c mice. Noncompetitive and competitive indirect ELISA were employed to screen positive cell clones. A caprylic acid ammonium sulphate (CAAP) method was used to purify NT mAb, and the Batty saturation method was used to determine the affinity constant (Kaff).

RESULTS

Five hybridoma cell lines, named NT-1, NT-2, NT-3, NT-4, and NT-5, were identified and their corresponding mAbs were of the IgG(1) isotype with a k light chain. The Kaffs of all mAbs were between 2.6 and 4.7 × 10(9) L/mol. The titers and IC(50) values of purified ascite fluids were in the range of (0.64-2.56) × 10(5) and (0.55-1.0) ng/mL, respectively. Of all the cross-reacting steroids, (-NT was the most reactive with the mAbs at 62% with NT-1 mAb and 64% with NT-2 mAb. Negligible cross-reactivity (<0.01%) with other steroids was observed.

CONCLUSION

The establishment of these hybridomas allows the potential development of a rapid test kit, and may provide an alternative method for the detection of NT residues in food producing animals.

Contribution of electron microscopy to the study of neuropathies associated with an IgG monoclonal paraproteinemia

A typical monoclonal IgG dysglobulinemia whether benign (monoclonal gammopathy of undetermined significance, MGUS) or malignant can give rise to peripheral neuropathy by damaging nerves. At first, neurotoxicity of the chemotherapy if the patient is treated must be ruled out in such cases. Indeed, a variety of other mechanisms have been described: endoneurial deposits of immunoglobulin, infiltration of the immunoglobulin within myelin sheaths, POEMS syndrome, deposits of amyloid, chronic inflammatory demyelinating polyradiculoneuropathy and infiltration of malignant cells. Ultrastructural examination of a nerve biopsy can be decisive in combination with routine histological and immunopathological examinations. Characterization of the mechanism of the neuropathy in a dysglobulinemic context is important as it governs therapeutic options, which in certain cases are particularly beneficial.