Kappa Light Chain Restriction Research Articles

Hemato-Renal Profile of Proliferative Glomerulonephritis with Monoclonal Immunoglobulin Deposits

Background Proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) is a rare entity classified under the umbrella of monoclonal gammopathy of renal significance. The clinical implications of circulating monoclonal immunoglobulin (MIg), light chain restriction on immunofluorescence (IF) microscopy, histopathological pattern, and type of therapy on renal outcomes are not clearly defined. Materials and Methods Sixteen patients of PGNMID diagnosed between 2013 and 2020 were included from a biopsy registry of 11,459 patients at a single center. Follow-up data was collected from electronic medical records until June 2021. Results The mean age of the cohort was 41.7 ± 13.5 years. Forty-four (7/16) percent showed monoclonal protein on serum or urine electrophoresis, 25% (3/12) had IgG kappa by serum immunofixation electrophoresis (IFE) and 38% (5/13) had abnormal kappa: lambda free light chain (FLC) ratio. The predominant light microscopy pattern, membranoproliferative glomerulonephritis (MPGN) was seen in 7/16 (43.7%) patients. The predominant heavy chain detected by IF microscopy was IgG (13/16, 81.3%). Kappa and lambda light chain restriction were seen in 56.3 (9/16) and 43.8 (7/16) percent of patients respectively. Circulating monoclonal kappa light chains were detected in 50 and 29% of kappa-PGNMID patients by IFE and FLC assay respectively. None of the lambda-PGNMID patients had detectable circulating monoclonal lambda light chains. Patients with circulating MIg had more proteinuria, lower estimated glomerular filtration rate, and a higher percentage of plasma cells on bone marrow biopsy. Thirty-eight percent of our cohort (5/13) progressed to kidney failure over a median (range) period of 3 (IQR, 1-7) months. Of these, 4/5 received immunosuppression, and 1/5 were treated with plasma cell-targeted chemotherapy. Conclusion PGNMID is a rare disease with a biopsy incidence of 0.1%. Only a quarter of patients with PGNMID have circulating MIg. Presence of circulating MIg, type of monoclonal light chain restriction in kidney biopsy, and type of therapy did not predict renal outcomes. Patients with MPGN pattern had favorable renal outcomes despite a higher degree of proteinuria at presentation.

Proliferative glomerulonephritis with monoclonal IgG deposits in an adolescent successfully treated with daratumumab

AbstractThere is no specific treatment for proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID), a disease that is very rare in the pediatric population. We report the case of a 15-year-old boy who presented with mildly reduced kidney function and nephrotic syndrome. Kidney biopsy revealed PGNMID with monoclonal deposits of IgG3 with kappa light chain restriction. Flow cytometry showed a significant CD38 plasma cell population in the peripheral blood in the absence of other signs of hematological malignancy. The patient was treated with a 6-month course of daratumumab, a monoclonal antibody targeting CD38. There was a significant reduction in proteinuria and normalization of kidney function. Based on positive experience with adults, daratumumab should also be studied in children with PGNMID.

ALK-positive large B-cell lymphoma (ALK + LBCL) with aberrant CD3 expression

ALK-positive ( +) large B cell lymphoma (ALK + LBCL) is a rare distinct subtype of diffuse large B cell lymphoma presenting with high stage and aggressive behavior. Although B cell markers such as CD20, CD19, and CD22 are generally negative, plasmacytic markers including CD138, CD38, and MUM1 are positive. T cell markers are negative with rare exceptions. We report an unusual case of ALK1 + LBCL in a 58-year-old man with partial expression of CD3 without other T cell antigen expression. The tissue was evaluated with flow cytometry, immunohistochemistry, fluorescent in situ hybridization, and gene rearrangement studies. Gene rearrangement studies for IGH and TCR gamma were performed. Flow cytometry did not demonstrate any abnormal lymphoid populations. Tissue sectioning shows a malignant plasmacytic large cell neoplasm which expresses CD45 but is negative for CD20, CD79a, and PAX5. Plasmacytic markers CD138 and MUM1 are positive with kappa light chain restriction. Strong granular cytoplasmic expression of ALK is present. FISH showing disrupted ALK supports the diagnosis while MYC, BCL6, and BCL2 are intact. Gene rearrangement studies show coexisting IGH and TCR gamma clones; however, the TCR peak was present within a polyclonal background suggesting the disputed cells are likely only a subset of the T cell population. ALK + LBCL can present with an ambiguous immunophenotype, which warrants the use of multiple B cell, T cell, and plasmacytic antibodies. CD3 expression in this entity is rare and of uncertain clinical significance, but warrants further study.

85 IgA Nephropathy with Mesangial Kappa Light Chain Restriction

85 IgA Nephropathy with Mesangial Kappa Light Chain Restriction

Asymptomatic skin lesions as a diagnostic clue in multiple myeloma – A case report

Multiple myeloma (MM) is a rare cancer of plasma cells in the bone marrow. Cutaneous plasmacytoma is an uncommon but specific skin lesion in MM with an incidence of 2%. Cutaneous plasma cell infiltration in pre-existing MM is a very rare phenomenon, with approximately 100 cases described in the literature. Here, we report a case of a 61-year-old male who presented with asymptomatic skin nodules and plaques over the chest, abdomen, and back of the trunk for five months. Histopathological examination showed mononuclear cells with moderate cytoplasm and round to ovoid nuclei. Immunohistochemistry showed CD138 and kappa positivity and lambda and CD20 negativity, confirming the diagnosis of cutaneous plasmacytoma. Bone marrow biopsy and immunohistochemistry revealed bone marrow plasmacytosis with kappa light chain restriction. Serum free light chain ratio was 106.61 and fluorescence in situ hybridization showed del 13q. The clinical features and investigations fulfilled the diagnostic criteria for MM, and the patient was started on chemotherapy, following which the skin lesions improved. Development of skin lesions is seen in the advanced stages of MM and is considered a bad prognostic sign. However, they can also be seen as initial manifestations of the disease, as in this case. Hence, meticulous investigations and early diagnosis are of paramount importance.

Lymphoplasmacytic Lymphoma: An Atypical Presentation with IgG Monoclonal Gammopathy

Introduction Lymphocytic lymphoma (LPL) is a rare type of low-grade mature B-cell non-Hodgkin lymphoma, characterized by a monoclonal population of B lymphocytes, lymphoplasmacytic cells, and plasma cells. In around 95% of LPL cases, the serum immunoglobulin M (IgM) paraprotein is increased, which is correlated to Waldenstrom's Macroglobulinemia (WM), a clinicopathological disease. Only around 5% of LPL cases are associated with the serum paraproteins immunoglobulin G (IgG) or immunoglobulin A (IgA), or light chains alone, or are not linked to a paraprotein. Non-IgM LPLs have a wide range of clinical and pathological features, and MYD88 L265P mutations can occur, though at a lower frequency than WM. Hence, MYD88 testing is advised for prospective therapeutic purposes. Case Presentation A 69-year-old male was referred to a hematologist for uncontrolled epistaxis and periorbital edema. On initial workup, he had high total protein, elevated globulin, hypoalbuminemia, anemia, and proteinuria. Further investigation revealed a high IgG level with low IgM, IgA, and complement levels. Serum Protein Electrophoresis (SPEP): Increased total protein, decreased alpha two and beta globulins with a large monoclonal protein peak migrating in the gamma region, which accounts for 4.77 g/dl of the total 5.38g/dl gamma. Elevated Kappa Quantitative Free Light Chains of 355.39 (3.30 - 19.40mg/L), Decreased Lambda Quantitative Free Light Chains of 1.51 (5.71 - 26.30mg/L), Elevated Kappa Lambda Free Light Chains Ratio of 235.36 (0.26 - 1.65). Serum ImmunoFixation Electrophoresis demonstrated IgG-type kappa monoclonal protein with an additional faint band in IgG kappa. X-Ray skeletal survey showed a possible small lytic area in the inferior aspect of the C2 vertebral body, prompting him to have a cervical spine MRI which revealed no lytic lesions but an 18 mm vertebral body hemangioma inside T2. Molecular testing was positive for MYD88 Mutation c.794T>C (p. L265P) and negative for CXCR4 mutation. Plasma cell myeloma prognostic panel and chromosome analysis were normal. Flow cytometry of bone marrow aspirate showed a kappa light chain restricted plasma cell population (1.6% of total cells) with the following immunophenotype: positive for CD138, CD38, CD45, and negative for CD19, CD20, CD56, CD 117, and lambda light chains. The B-cell population showed kappa light chain restriction with the following immunophenotype: positive for CD19, CD20, and kappa light chains and negative for CD5, CD10, CD11c, CD23, and lambda light chains (Image 2). PET-CT of the whole body was negative for the extension of the disease. Transfusion with the two least incompatible PRBCs had little effect. However, plasmapheresis significantly improved his hemoglobin level by less than 7g/dl. A bone marrow biopsy revealed he had LPL with IgG Monoclonal Gammopathy (Image 1). He received one cycle of CyBorD (Cyclophosphamide, Bortezomib, Dexamethasone), followed by seven cycles of KCD (Carfilzomib, Cyclophosphamide, Dexamethasone) and Rituximab. The patient was diagnosed with low-grade B cell lymphoma with plasmocytic differentiation/lymphoplasmacytic lymphoma, with MYD88 mutation c.794T>C (p. L265P) positivity and CXCR4 mutation negativity. After plasmapheresis, the IgG level dropped to 1958. Follow-up SPEP revealed decreased alpha2 and beta globulins, decreased free lambda light chains, and increased K/L ratio. The patient was treated with Acalabrutinib, and his anemia, epistaxis, and coagulopathy resolved. Repeat PET-CT scan revealed no evidence of illness progression. Discussion LPL is not always linked with IgM monoclonal gammopathy; it can also be associated with IgG or IgA monoclonal gammopathy, light chains alone, or no monoclonal paraprotein. Non-IgM LPL has a high prevalence of extramedullary involvement, a lower rate of MYD88 mutation, and few hyper viscosity symptoms. The MYD88 mutation does not allow WM and Non-IgM LPL to be distinguished from other lymphoproliferative disorders with similar clinical and immunophenotypic features. The case described is unique as the patient has high levels of IgG (11,200) at presentation. In contrast to our patient, who has LPL with IgG Monoclonal gammopathy, approximately 95 percent of LPL patients have IgM Monoclonal gammopathy, which corresponds with WM. As a result, clinicians should be on the lookout for LPL that lacks an IgM Monoclonal Paraprotein.

DP25 Widespread subcutaneous nodular kappa light chain amyloidosis

Abstract A 69-year-old woman was referred to the dermatology department for evaluation of multiple widespread subcutaneous lesions involving the neck, torso and limbs. These lesions, initially diagnosed in the community as lipomas, had been slowly progressing in size and number for 3 years. She had remained systemically well. Her only medical history was essential thrombocythaemia. She took no regular medication. On examination, there were multiple subcutaneous lesions appreciated on palpation with no overlying epidermal change. The patient was experiencing pain in a sciatic distribution. Magnetic resonance imaging of the femur showed a 12-cm enhancing area of subcutaneous nodularity encasing the sciatic nerve. Computed tomography of the chest, abdomen and pelvis showed multiple subcutaneous, ill-defined, soft tissue lesions of the anterior abdominal wall with no lymphadenopathy or organ abnormality. Deep incisional biopsies from two separate locations were completed. There was an unremarkable epidermis and dermis. In the subcutaneous fat, the septae appeared thickened alongside thickened elastic fibres and a prominent multifocal granulomatous reaction with a high degree of elastophagocytosis. There were multifocal aggregates of plasma cells that displayed no cytological atypia. In situ hybridization showed strong kappa light chain restriction. Plasma protein electrophoresis was completed and confirmed a paraprotein band in the gamma region of IgM kappa. Full blood count revealed a high platelet count (585 × 109 cells L–1) but was otherwise unremarkable alongside normal renal and liver function, bone profile, lactate dehydrogenase, B2 microglobulin, Bence–Jones proteins and infection screen. A Congo red stain was performed on the original histological samples. This showed apple green birefringence under polarized light-confirming amyloid. Haematology completed a bone marrow biopsy, which was normal. Referral to the National Amyloid Centre was made. Serum amyloid P scan showed no visceral involvement. A diagnosis of subcutaneous amyloid kappa light chain subtype (AL) was made. The patient has since commenced rituximab, bortezomib (Velcade®), cyclophosphamide and dexamethasone (R-VCD) chemotherapy at 4-weekly intervals over a 4-month period. Primary localized cutaneous amyloidosis is characterized by extracellular deposition of amyloid protein in the skin without evidence of systemic involvement and is often subtyped into macular, papular and nodular. Amyloidoma (tumoral amyloidosis) is rare and defined as a solitary localized deposit of amyloid. There are only four case reports in the literature of multiple subcutaneous amyloid deposits, and only one of these cases was of AL (light chain) vs. amyloid A (AA) subtype. This case showed nodules restricted to the neck (Nguyen TU, Oghalai JS, McGregor DK et al. Subcutaneous nodular amyloidosis: a case report and review of the literature. Hum Pathol 2001; 32:346–8). To our knowledge, this is the first case of widespread kappa light chain subcutaneous amyloidosis.

#6227 SPONTANEOUS REMISSION OF MEMBRANOUS VARIANT OF PGNMID WITH MONOCLONAL IGG2κ

Abstract Background and Aims The clinical significance of the morphological patterns of glomerular injury and of each IgG subclass in proliferative glomerulonephritis (GN) with monoclonal immunoglobulin deposits (PGNMID) is not well understood. Literature suggests that PGNMID with certain histological features such as membranous or mesangio-proliferative features or non-IgG3 subclass staining may be associated with a more favourable renal prognosis. We present a patient with membranous variant of PGNMID with monoclonal IgG2κ who had spontaneous remission without recurrence over a 2-year follow-up. Method Not applicable Results A 62-year-old Malay gentleman presented with new onset nephrotic range proteinuria, on a background of type 2 diabetes mellitus with diabetic duration of 5 years, hypertension and hyperlipidemia. He was mildly hypertensive (blood pressure 148/87) and non-edematous at presentation. Investigations revealed preserved kidney function [serum creatinine (sCr) 66µmol/L], bland urinalysis, and 24-hour urinary total protein (UTP) of 3.74g/day. Serum albumin (sAlb) was 35g/L. Serum complements were not low. Autoimmune markers inclusive of anti-double stranded DNA antibodies, anti-neutrophil cytoplasmic antibodies, and anti-phospholipase A2 receptor (PLA2R) antibodies were negative. Viral serologies were also unremarkable. No monoclonal band was detected on serum electrophoresis, while serum immunofixation was not performed. Kidneys were normal sized. Renal biopsy performed demonstrated 28 glomeruli, of which only 1 was globally sclerosed. Glomeruli capillary walls were diffusely thickened by vacuolations. Capillary loops were mostly single contoured although occasional focal double contouring was seen. Masson trichome stain revealed fuchsinophilic subepithelial immune deposits while periodic acid methenamine silver stain showed argyrophilic basement membrane spikes. Variable mesangial expansion and hypercellularity was observed, as well as mesangiolysis. Focal leukocyte margination was present, but significant endocapillary proliferation was not seen. There were no Kimmelstiel-Wilson lesions. Tubular atrophy with interstitial fibrosis was overall mild (10% of parenchymal area) and there were no tubulointerstitial infiltrates. Immunofluoresence showed granular staining of IgG (1-2+), C3 (2-3+) along glomerular capillary walls, as well as presence of kappa light chain restriction (κ 1-2+; λ negative in glomeruli). Immunostaining for PLA2R was negative. IgG subclass analysis performed in view of kappa restriction revealed isolated deposition of IgG2. Electron microscopy was not available. Overall findings were most consistent with membranous variant of PGNMID with monoclonal IgG2κ. Age-appropriate and symptom-directed malignancy screening did not reveal significant abnormalities. Given that the patient was minimally symptomatic, a trial of conservative therapy was initiated with optimized non-immunosuppressive anti-proteinuric therapy using renin-angiotensin-aldosterone and sodium-glucose co-transporter-2 inhibitors. Gradual spontaneous remission was observed without recurrence over 2 years of follow-up (sCr 77µmol/L; sAlb 40g/L; 24-hour UTP 0.22g/day). Conclusion Our case adds to the literature that a membranous variant of PGNMID with monoclonal IgG2κ may be associated with better renal outcomes. Despite the lack of proliferative changes, it is possible that membranous variants may share similar underlying disease mechanisms as the other proliferative variants. Large international registries to allow the correlation of morphological features and IgG subclasses with clinical outcomes are required to confirm our observation.

Primary Cutaneous Marginal Zone Lymphoproliferative Disorder of Donor Origin after Allogeneic Hematopoietic Stem Cell Transplantation.

Primary cutaneous posttransplant lymphoproliferative disorders (PTLDs) after allogeneic hematopoietic stem cell transplant (allo-HSCT) are exceedingly rare, with only 6 published cases, all of them consisting in T-cell neoplasms. In this report, we present for the first time a donor-derived B-cell PTLD consisting in a primary, cutaneous, B-cell, marginal zone, lymphoproliferative disorder (PCMZLPD). The patient, a 37-year-old woman with a history of Hodgkin lymphoma received an allo-HSCT from her healthy, matched, related father, achieving complete host chimerism in the bone marrow and peripheral blood. However, 8 years after the allo-HSCT, she presented asymptomatic skin lesions consisting in oval, well-defined, slightly raised erythematous plaques, located on the arms, trunk, and legs. Skin biopsies of 2 lesions demonstrated a class-switched IgG+, EBV-, PCMZLPD, showing kappa light chain restriction and monoclonal rearrangement of the IgH gene. Microsatellite genotyping and 2-color fluorescence in situ hybridization (X and Y chromosomes) confirmed that the origin of the neoplastic cells was the donor graft. The lesions showed an indolent behavior, good response to topical corticosteroids, and no need for systemic treatment. Our case broadens the spectrum of PTLD, a diverse group of lymphoid and/or plasmacytic proliferations with variable clinical presentations and histopathological features.

Solitary extramedullary plasmacytoma of the gingiva—A case report with literature review

Abstract Extramedullary solitary plasmacytoma (EMP) is a plasma cell neoplasm involving the soft tissues without the involvement of the bone marrow. In this case report, we present an isolated soft tissue growth on the lingual gingiva of the left mandibular canine-premolar region diagnosed as EMP based on clinical, histological, and laboratory results. Orthopantomogram and occlusal radiographs showed no osteolytic lesions. Hematoxylin and Eosin staining showed sheets of inflammatory cells, predominantly atypical plasma cells with varying degrees of differentiation showing features of pleomorphism, and multinucleated giant cells with intervening collagen fibers. Positive immunoreactivity for CD56, CD138, and kappa light chain restriction were observed. Serum protein electrophoresis demonstrated an increase in IgA levels and immunofixation electrophoresis confirmed the presence of the M band in the IgG and kappa lanes, indicating monoclonal gammopathies. Based on the above findings, the case was diagnosed as EMP; the consultant pathologist, however, recommended excluding multiple myeloma.

Plasmablastic MyelomaA Diagnostic Dilemma

Plasmablastic neoplasms comprise various haematolymphoid tumours with plasmablastic morphology which includes Plasmablastic Myeloma (PBM) and Plasmablastic Lymphoma (PBL). Distinguishing these two entities remains a major diagnostic challenge. In view of Epstein Barr Virus (EBV)-Encoded RNA (EBER) negativity, Human Immunodeficiency Virus (HIV) negativity, high Serum Free Light Chain (SFLC) assay and absence of hypermetabolic lymphadenopathy, a final diagnosis of PBM was made. This report is about a 55-year-old lady who presented with fatigue, significant loss of weight, and appetite. She had mild enlargement of the liver, spleen and no significant lymphadenopathy. There were atypical cells in peripheral blood. Bone marrow evaluation showed 51% atypical mononuclear cells. Flow cytometry was negative for acute leukaemia diagnostic markers. Immunohistochemistry (IHC) on the bone marrow biopsy revealed positivity for Cluster of Differentiation (CD) 138, Multiple Myeloma 1 (MUM1) with kappa light chain restriction and negative for EBER. The free light chain showed a kappa:lambda light chain ratio of 28,885 (0.26-1.65). The diagnosis of PBM was made and she was started on a daratumumab-based immunotherapy regimen. She achieved complete remission after induction with Measurable Residual Disease (MRD) <0.01%. She is presently doing well on follow-up with the disease in remission status.

Comparison Of Histomorphology, Angiogenesis and Proliferation in Kappa and Lambda Restricted Plasma Cell Myelomas with Its Effect on Prognosis

Aims Of the Study: To study the type of light chain restriction and correlate it with the morphological parameters, proliferation index, angiogenesis and clinical parameters. Materials And Methods: The study includes 46 cases of myeloma diagnosed over the period of five years. The histomorphological features like plasma cell morphology, percentage of plasma cells and pattern of infiltration were studied. Immunohistochemistry for kappa and lambda light chains was done. Angiogenesis was assessed by calculating the microvessel density (MVD) using anti CD34 immunohistochemistry. Proliferation was assessed immunohistochemically using Ki67 by comparing with anti CD38 which was used to highlight the plasma cells. Results: The cases with kappa light chain restriction had significantly less of poorly differentiated morphology (7.4% vs 36.8%; p=0.02) and diffuse pattern of infiltration (22% vs 63%; p=0.01) compared to lambda. The kappa group also had lower MVD (9.9 vs 16.5; p=0.02) and proliferation index (4.7 vs 94; p=0.04) compared to the lambda. Conclusion: Therefore, the type of light chain restriction is also a prognostic factor in plasma cell myeloma.

Primary cutaneous blastic marginal zone lymphoma: A comprehensive clinical, light microscopic, phenotypic and cytogenetic appraisal

BackgroundPrimary cutaneous marginal zone lymphoma (PCMZL) is a form of indolent lymphoproliferative disease where the disease is largely a cutaneous confined process. It is typically a neoplasm composed of post germinal small B-cells and light chain restricted plasma cells in a background of reactive T-cell hyperplasia and benign germinal centers. Rarely a significant degree of large cell infiltration occurs warranting the categorization as blastic marginal zone lymphoma. Materials and methodsWe reviewed our data base over a time period of 2016 to 2022 for cases diagnosed as blastic MZL. Twelve cases were identified. The clinical records and pathological data were reviewed. ResultsNine of the cases represented de novo forms of blastic MZL while in three cases there was a prior history of MZL. Multifocal cutaneous disease was not uncommon and one quarter of the cases had evidence of extracutaneous dissemination. All patients except three achieved remission with varied therapeutic interventions depending on the extent of the disease ranging from conservative re-excision to chemotherapy. No patient died from lymphoma. Light microscopically, there was evidence of a background of conventional MZL in the majority of cases. The large cell component was typically characterized by multiple micronodular aggregates throughout the dermis although in three cases there was a striking diffuse large cell component as the dominant infiltrate. Phenotypically, a third of the cases showed either CD5 or CD23 positivity amidst neoplastic B cells. Significant staining for BCL-2 was noted in the majority of cases tested while extensive MUM-1 positivity was observed in half of the cases tested. Kappa or lambda light chain restriction was seen in most. The Ki67 proliferation index exceeded 30 % in all cases. There was C-MYC positivity in two cases. While most cases did not detect cytogenetic abnormalities, one case had multiple cytogenetic hits that are associated with diffuse large B cell lymphoma. Next generation sequencing showed a Ten-eleven translocation 2 mutation in the earlier biopsy prior to transformation and in the later biopsy after transformation along with an additional B2M mutation in the transformed biopsy. Both types of mutations are very uncommon but held to contribute to tumor progression in the setting of diffuse large B cell lymphoma. ConclusionBlastic MZL is associated with a more aggressive clinical course. Even when there is disseminated disease patients while not always cured did not have a fatal course in this series. The light microscopic findings are reproducible. The background of MZL, identification of larger cells in significant numbers without a follicle center phenotype, at times expressing CD5 or CD23 with variable positivity for MUM1, BCL-2 and C-MYC and a high proliferation index define the pathology in most. Certain cytogenetic abnormalities and genetic mutations implicated in large cell transformation into a diffuse large B cell lymphoma are seen in blastic MZL with earlier biopsies prior to transformation potentially harboring at risk genetic mutations.

A Rare Presentation of Primary Plasma Cell Leukemia: A Case Report and Review of Literature

Background: The primary plasma cell leukemia (pPCL) is an aggressive plasma cell neoplasm. It is diagnosed by the presence of an absolute plasma cell count of >2 × 109/L or 20% plasma cells in the peripheral blood. pPCL is rare and reported to be <1 in a million. Hence, our case report is a rare opportunity to describe clinical presentation and management of pPCL. Case Details: A 72-year-old male patient with benign prostatic hyperplasia, presented to the hospital for cough, breathlessness, and intermittent fever of one month. On arrival, he was tachypnoeic with altered sensorium and rales in his chest. Laboratory examination showed anemia, leucocytosis, and thrombocytopenia. The peripheral blood smears revealed 25-30% circulating atypical plasmacytoid cells. Flow cytometry on the peripheral blood revealed 58.7% lymphoid cells. Out of the total lymphoid cells, 73.6 % cells were characterized by expression of CD38, CD138, CD19, CD49d, CD43, CD27, CD81 (96.9% dim positives) CD 56 with dim kappa light chain restriction suggestive of PCL. Furthermore, serum protein electrophoresis and serum immunofixation showed an M-band (0.53g) of IgG kappa subtype. However, the patient developed lower respiratory tract infections with multi-organ dysfunction and he succumbed to the same.Conclusion: The prognosis of pPCL is very poor and the high risk of infective complications. Early diagnosis and optimal chemotherapy would be the key to the management. Detailed peripheral blood film examination and characterization of abnormal cells with immune phenotyping are of utmost importance in diagnosing pPCL.

Extranodal Marginal Zone Lymphoma of the Thyroid with Extensive Amyloid Deposition: A Rare Case Presentation

Abstract Introduction/Objective Extranodal marginal zone lymphoma (MZL) is a rare indolent tumor with the potential of recurrence and systemic spread. Thyroid involvement is infrequently reported, and generally seen in the context of Hashimoto thyroiditis. Additionally, amyloid deposition is an exceptional complication of extranodal MZL. We report an unusual case of a 65-year-old woman with a rapidly growing symptomatic nodule of the right thyroid lobe and a previous inconclusive FNA showing benign lymphoid tissue. She was taken to the OR for diagnostic right thyroid lobectomy with neck level 6 dissection. Methods/Case Report The specimen was sent for histologic evaluation, and showed thyroid with marked amyloid deposition, highlighted by Congo Red special stain, distorting normal architecture. Additionally, significant small atypical lymphoid infiltrate was present. Neoplastic lymphocytes were positive for CD20, PAX5 and CD43. Kappa light chain restriction by kappa ISH stain indicated monoclonality. Conversely, CD138, CD10, BCL6 and CyclinD were negative. Ki-67 demonstrated a 15-20% proliferation index. The germinal centers of the secondary follicles demonstrated diminished CD10 and BCL-6 consistent with follicular colonization by neoplastic lymphocytes. One of the regional lymph nodes displayed involvement by lymphoma with amyloid deposition. Medullary carcinoma of the thyroid was ruled out on the basis of incompatible histologic and immunohistochemical profile. Results (if a Case Study enter NA) NA Conclusion While Medullary carcinoma and amyloid goiter are among the top differentials for extensive amyloid deposition in the thyroid gland, we illustrate the need for judicious review of clinical history and careful consideration of immunohistochemistry workup to establish the unusual diagnosis of extranodal MZL of the thyroid with extensive amyloid deposition.

Clinic-pathological characteristics of rare tubulointerstitial diseases.

Tubulointerstitial diseases is one of the common causes of renal dysfunction. Some rare pathological types are easy to be misdiagnosed and missedly diagnosed because of their low prevalence and relatively insufficient understanding, which affects the treatment and prognosis of patients. This study aims to explore clinical manifestations and pathological characteristics of several rare tubulointerstitial diseases, and therefore to improve their diagnosis and treatment. A total of 9 363 patients diagnosed by renal biopsy in the Department of Nephrology, Second Xiangya Hospital, Central South University from November 2011 to September 2021 were selected. Six cases of light chain cast nephropathy (LCCN), 2 cases of light chain proximal tubulopathy (LCPT), 1 case of LCCN with LCPT, 4 cases of genetic tubulointerstitial disease, and 6 cases of non-genetic related tubulointerstitial lesion were screened out, and their clinical manifestations and renal biopsy pathological results were collected, compared, and analyzed. Patients with LCCN presented with mild to moderate anemia, microscopic hematuria, and mild to moderate proteinuria. Compared with patients with LCPT, proteinuria and anemia were more prominent in patients with LCCN. Five patients with LCCN and 2 patients with LCPT had elevated serum free kappa light chain. Five patients with LCCN presented clinically with acute kidney injury (AKI). Two patients with LCPT and 1 patient with LCCN and LCPT showed CKD combined with AKI, and 1 LCPT patient presented with typical Fanconi syndrome (FS). Five patients with LCCN, 2 patients with LCPT, and 1 patient with LCCN and LCPT were diagnosed with multiple myeloma. Five patients with LCCN had kappa light chain restriction in tubules on immunofluorescence and a "fractured" protein casts with pale periodic acid-Schiff (PAS) staining on light microscopy. Immunohistochemical staining of 2 LCPT patients showed strongly positive kappa light chain staining in the proximal tubular epithelial cells. And monoclonal light chain crystals in crystalline LCPT and abnormal lysosomes and different morphological inclusion bodies in noncrystalline LCPT were observed under the electron microscope. Six patients with LCCN were mainly treated by chemotherapy. Renal function was deteriorated in 1 patient, was stable in 4 patients, and was improved in 1 patient. Two patients with LCPT improved their renal function after chemotherapy. Four patients with genetic tubulointerstitial disease were clinically presented as CKD, mostly mild proteinuria, with or without microscopic hematuria, and also presented with hyperuricemia, urine glucose under normal blood glucose, anemia, polycystic kidneys. Only 1 case had a clear family history, and the diagnosis was mainly based on renal pathological characteristics and genetic testing. Compared with patients with non-genetic related tubulointerstitial lesion, patients with genetic tubulointerstitial disease had an earlier age of onset, higher blood uric acid, lower Hb and estiated glomemlar fitration (eGFR), and less edema and hypertension. Renal pathology of genetic tubulointerstitial disease presented tubular atrophy and interstitial fibrosis, abnormal tubular dilation, glomerular capsuledilation, and glomerular capillary loop shrinkage. Glomerular dysplasia and varying degrees of glomerular sclerosis were observed. Genetic tubulointerstitial disease patients were mainly treated with enteral dialysis, hypouricemic and hypoglycemic treatment. Two genetic tubulointerstitial disease patients had significantly deteriorated renal function, and 2 patients had stable renal function. Patients with AKI or FS, who present serum immunofixation electrophoresis and/or serum free kappa light chain abnormalities, should be alert to LCCN or LCPT. Renal biopsy is a critical detection for diagnosis of LCCN and LCPT. Chemotherapy and stem cell transplantation could delay progression of renal function in patients with LCCN and LCPT. If the non-atrophic area of the renal interstitium presents glomerular capsule dilatation, glomerular capillary loop shrinkage, and abnormal tubular dilatation under the light microscopy, genetic tubulointerstitial disease might be considered, which should be traced to family history and can be diagnosed by genetic testing.

IgD multiple myeloma: biology, diagnosis, and treatment

IgD multiple myeloma is uncommon. Patients generally present at a younger age and have shorter progression free and overall survivals (OSs). Its rarity has inhibited development of a specific risk stratification system or informed best treatment protocols. We present interphase fluorescence in situ hybridization results from a group of 29 cases. These showed evidence of a decreased male to female ratio, decreased OS in patients aged 70 and over, better outcomes in those with kappa light chain restriction, and CD56 positive patients had longer survivals than those lacking CD56. We discuss the biology of IgD multiple myeloma, the need for prospective studies, and challenges for improvements in diagnosis and treatment. We suggest an International Register to accelerate development of best practice guidelines for diagnosis, risk stratification, and treatment.

IgG kappa multiple myeloma with isolated central nervous system relapse.

A 76-year-old male presented with acute renal failure and cast nephropathy was diagnosed with IgG kappa multiple myeloma (MM). His paraprotein was 40 g/L, kappa-free light chain level was 17,058 mg/L, kappa: lambda light chain ratio was 1445. An automated full blood count showed hemoglobin 90 g/L, white blood cells 2.96 × 109/L, neutrophil 1.7 × 109/L, and platelet 179 × 109/L. Bone marrow trephine sample was hypercellular with nearly 100% plasma cells, which were positive for CD138, CD56, and cyclin D1, and showed kappa light chain restriction. Fluorescence in situ hybridization analysis with dual color/dual probes for immunoglobulin heavy chain (IGH) and MYC genes (Cytocell) and whole genome screening using 8 × 60K oligonucleotide arrays (Agilent) performed on the CD138 enriched cells (CD138 microbeads Miltenyi Biotech) from the liquid bone marrow sample showed no evidence of IGH rearrangement, MYC rearrangement, 1q gain, 1p loss, 17p loss, or any clinically significant imbalance. He was treated with eight cycles of bortezomib, cyclophosphamide, and dexamethasone (VCD) to very good partial response. He relapsed 30 months after diagnosis with paraprotein of 36 g/L, kappa light chains of 10,000 mg/L, and creatinine of 498 μmol/L. He was treated with eight cycles of bortezomib, thalidomide, and dexamethasone (VTD) to paraprotein undetectable and kappa light chain 29 mg/L. Seven months post completion of VTD (4 years after myeloma diagnosis), he presented with abnormal gait, falls, and a left-sided facial droop. His paraprotein was 2 g/L and serum-free kappa light chain was 81 mg/L. Magnetic resonance imaging (MRI) head and whole spine showed multifocal diseases in spinal canal and intracranially, involving the cranial nerves most prominent the fifth, seventh, eighth, and hypoglossal nerve on the left, anterior surface of the inferior pons medulla (Figure 1A). There were multiple lesions in the cervical spine as well as in the thoracic spine (Figure 1B). Computerized tomography (CT) chest abdomen pelvis did not show the evidence of other new diseases. Plasma cells were detected in cerebral spinal fluid (CSF) (Figure 1C, May–Grünwald–Giemsa stain x100 objective). He was treated with pomalidomide and dexamethasone. Weekly cytarabine intrathecal (IT) treatment was given until the clearance of plasma cells from CSF samples for three times. Four months later, he achieved the complete remission on MRI head and whole spine with undetectable paraprotein and normal light chain ratio. Serial MRI scans confirmed ongoing remission. A year later, he relapsed again with worsening mobility and reappearance of myeloma cells in CSF. By flow cytometry, these cells were positive for CD138, CD38, CD56, CD117, and negative for CD19. MRI head showed leptomeningeal disease with a new 2.2 cm frontal lobe lesion. His paraprotein remained undetectable and kappa light chain remained at below 100 mg/L. He continued systemic pomalidomide and dexamethasone chemotherapy and received palliative whole brain radiotherapy 20 Gy in 5 fractions for symptom control. His disease continued progressing and he passed away 3 months later (5.5 years after myeloma diagnosis). Here, we reported a myeloma patient with isolated CNS relapse, who achieved 1 year of remission with combination of intrathecal chemotherapy and systemic pomalidomide and dexamethasone treatment, but sadly passed away 4 months after second CNS relapse. CNS MM is a rare form of extramedullary disease, but carries a very poor prognosis. The optimal approach to treatment of CNS MM is not currently known. The current approach includes systemic therapy with agents known to cross the blood brain barrier, intrathecal therapy, and CNS irradiation. Innovative approach to treatment is urgently needed. The authors received no specific funding for this work. Ke Xu and Lucy Kamuriwo wrote the manuscript. Ke Xu, Lucy Kamuriwo, Claire Anderson and Parag Jasani critically revised the final version of the manuscript. The authors declare they have no conflicts of interest. No written or verbal consent obtained from patient. Patient has passed away.

ORAL WALDENSTROM MACROGLOBULINEMIA

<h3>Objective</h3> Waldenstrom macroglobulinemia (WM) is a rare B-cell lymphoproliferative disorder that is characterized by bone marrow infiltration with lymphoplasmacytic cells and immunoglobulin M monoclonal gammopathy. The extramedullary infiltration of WM is uncommon but predicts a worse prognosis. To date, there has been only 1 reported case of biopsy-proven oral manifestation of WM. <h3>Case Summary</h3> A 72-year-old man with a medical history significant for hypertension and WM, which was in good clinical and laboratory control on ibrutinib, a Bruton tyrosine kinase inhibitor, for the past 4 years, was referred by his dentist for evaluation of an asymptomatic palatal mass. The patient was known to have medication-related osteonecrosis of the jaw stage 1 of left mandible. This was secondary to Zometa prescribed to address skeletal involvement of WM. Intraoral examination demonstrated a firm, nontender, 3 × 3 cm sessile mass with surface ulcerations involving the right hard and soft palate. A panoramic radiograph did not reveal any right maxillary sinus pathology, any central lesion, or any periapical radiolucency associated with the right maxillary teeth. A biopsy of the lesion was obtained. The pathology report indicated diffuse infiltration of small to intermediate-sized lymphoplasmacytic cells within the lamina propria that were positive for B-cell markers CD19, CD20, and CD22 (on immunoperoxidase studies) with kappa light chain restriction (with in situ hybridization) confirming the diagnosis of WM. This extramedullary manifestation of WM held great importance because it indicated disease progression in the context of his current management with ibrutinib. He underwent a bone marrow biopsy that demonstrated a previously undetected Bruton tyrosine kinase mutation. He was enrolled in a Phase 1 trial of dasatinib, a tyrosine kinase inhibitor. There was almost complete resolution of the palatal mass after 6-month systemic treatment with dasatinib. However, despite noted improvement in oral WM, the patient died 7 months later. <h3>Conclusions</h3> Although rare, oral health care providers should be cognizant of potential oral manifestation of WM and should communicate the findings to the oncology team because it can be of vital importance in the overall treatment plan. As in this case, the diagnosis of oral WM signified the progression of underlying malignancy.

Fine needle aspiration cytology of primary thyroid non-hodgkins lymphoma: Experience from a tertiary care center of North India.

Twelve cases of Primary Thyroid Non-Hodgkin's Lymphoma (PT-NHL) were retrieved from the records suspected or diagnosed as NHL on fine needle aspiration cytology (FNAC) over a period of nine years from 2010-2018. During this period 5236 patients underwent thyroid FNAC;of these 685 cases were diagnosed under Bethesda Caregory V and VI. Thyroid NHL constituted 0.23 % of all thyroid FNA (12/5236 cases)and 1.7% (12/685) of all thyroid malignancies. Patients ranged in age from 40-61 years with Female:Male 7:5. All patients presented with thyroid enlargement (5-14 cms), and were of two months to five years duration. Patients had history of tobacco intake (smoking/chewing)in nine cases (75%). Thyroid function tests showed hypothyroidism in four (33%), positive antithyroid antibodies in three (25%) and; two cases(16.7%) were known cases of Hashimotos thyroiditis with follow up. Eight cases (66.7%) had monomorphic large cell morphology,other four had mostly intermediate cell types (33.3%). A panel of immunocyto/ histochemistry (ICC/ IHC) showed CD 19 and CD 20 positivity in all cases;sixof these could be correlated on Flow cytometry (FC) with expression of FMC7, CD20, CD19 with kappa light chain restriction (5) and Lambda (1). FC findings corroborated completely with IHC on biopsy sections. The final diagnosis were Diffuse large B cell Lymphoma (DLBCL,8) and MALT- Lymphoma(4). The follow up was available in DLBCL (4) and MALT- Lymphoma (1). CHOP therapy were given in all patients followed by radiotherapy in DLBCL; one patient of DLBCL died following pulmonary complications, rest are well and alive on follow-up. PT-NHL is rare in India. DLBCL is the commonest histological type reported. In the present study, tobacco exposure has shown strong association. Combined FNAC-FC provide definitive diagnosis and thus can replace histopathology reducing turn around time. FNAC -FC provides a definitive diagnosis and thus can reduce turnaround time.