Nodal and extranodal plasmacytomas expressing immunoglobulin a: an indolent lymphoproliferative disorder with a low risk of clinical progression

Tissue Eosinophilia in B-cell Lymphoma: An Underrecognized Phenomenon

Tissue eosinophilia is seldom reported in B-cell lymphoma. It poses diagnostic challenges and frequently leads to the consideration of other diagnoses, particularly T-cell lymphomas. The scarce literature underscores the need for in-depth studies to enhance awareness and understanding of this phenomenon. We investigated 54 cases of B-cell lymphoma with notable tissue eosinophils, analyzing clinical information, hematoxylin and eosin staining, immunohistochemistry, and PCR-based clonality analysis. Nodal marginal zone lymphoma (NMZL) emerged as the most prevalent type (n=26), followed by B-cell lymphoma, not otherwise specified (n=13), diffuse large B-cell lymphoma (n=10), follicular lymphoma (n=2), chronic lymphocytic leukemia/small lymphocytic lymphoma (n=1), extranodal marginal zone lymphoma (n=1), and primary cutaneous marginal zone lymphoma (n=1). Shared features across different lymphoma types, best exemplified by NMZL, included plasmacytic differentiation (57.7%), increased vascularity (84.6%) with a tendency for perivascular distribution of neoplastic cells, and a tumor microenvironment abundant in T cells and histiocytes; some cases showed increased PD-1-positive cells. These features often raise consideration of angioimmunoblastic T-cell lymphoma. Along with clonality analysis, features supporting the diagnosis of B-cell lymphoma included cytological atypia in B cells rather than T cells, and the lack of follicular dendritic cell meshwork expansion. In addition, diffuse large B-cell lymphoma frequently exhibited interfollicular distribution and monocytoid appearance, indicating the possibility of transformed NMZL. Collectively, tissue eosinophilia can occur in diverse B-cell lymphomas but is most prevalent in tumors with a postgerminal stage of differentiation.

Plasma cell neoplasms and related entities-evolution in diagnosis and classification

Plasma cell neoplasms including multiple myeloma (MM) and related terminally differentiated B-cell neoplasms are characterized by secretion of monoclonal immunoglobulin and stepwise development from a preneoplastic clonal B and/or plasma cell proliferation called monoclonal gammopathy of undetermined significance (MGUS). Diagnosis of these disorders requires integration of clinical, laboratory, and morphological features. While their classification mostly remains unchanged compared to the revised 2016 WHO classification and the 2014 International Myeloma Working Group consensus, some changes in criteria and terminology were proposed in the 2022 International Consensus Classification (ICC) of mature lymphoid neoplasms. MGUS of IgM type is now divided into IgM MGUS of plasma cell type, precursor to the rare IgM MM and characterized by MM-type cytogenetics, lack of clonal B-cells and absence of MYD88 mutation, and IgM MGUS, NOS including the remaining cases. Primary cold agglutinin disease is recognized as a new entity. MM is now formally subdivided into cytogenetic groups, recognizing the importance of genetics for clinical features and prognosis. MM with recurrent genetic abnormalities includes MM with CCND family translocations, MM with MAF family translocations, MM with NSD2 translocation, and MM with hyperdiploidy, with the remaining cases classified as MM, NOS. For diagnosis of localized plasma cell tumors, solitary plasmacytoma of bone, and primary extraosseous plasmacytoma, the importance of excluding minimal bone marrow infiltration by flow cytometry is emphasized. Primary systemic amyloidosis is renamed immunoglobulin light chain amyloidosis (AL), and a localized AL amyloidosis is recognized as a distinct entity. This review summarizes the updates on plasma cell neoplasms and related entities proposed in the 2022 ICC. KEY POINTS: • Lymphoplasmacytic lymphoma can be diagnosed with lymphoplasmacytic aggregates in trephine biopsies < 10% of cellularity and evidence of clonal B-cells and plasma cells. • IgM MGUS is subdivided into a plasma cell type and a not otherwise specified (NOS) type. • Primary cold agglutinin disease is recognized as a new entity. • The term "multiple myeloma" replaces the term "plasma cell myeloma" used in the 2016 WHO classification. • Multiple myeloma is subdivided into 4 mutually exclusive cytogenetic groups and MM NOS. • Minimal bone marrow infiltration detected by flow cytometry is of major prognostic importance for solitary plasmacytoma of bone and to a lesser extent for primary extraosseous plasmacytoma. • Localized IG light chain amyloidosis is recognized as a separate entity, distinct from systemic immunoglobulin light chain (AL) amyloidosis.

Clinicopathologic and Molecular Characterization of Epstein-Barr Virus-positive Plasmacytoma

Epstein-Barr virus (EBV)-positive plasmacytoma is a rare plasma cell neoplasm. It remains unclear whether EBV-positive plasmacytoma represents a distinct entity or a variant of plasmacytoma. It shares morphologic features with plasmablastic lymphoma (PBL) and may cause diagnostic uncertainty. To better understand EBV-positive plasmacytoma and explore diagnostic criteria, this study describes 19 cases of EBV-positive plasmacytoma, compared with 27 cases of EBV-negative plasmacytoma and 48 cases of EBV-positive PBL. We reviewed the clinicopathologic findings and performed immunohistochemistry, in situ hybridization for EBV, fluorescence in situ hybridization for MYC , and next-generation sequencing. We found that 63.2% of patients with EBV-positive plasmacytoma were immunocompromised. Anaplastic features were observed in 7/19 cases. MYC rearrangement was found in 25.0% of them, and extra copies of MYC in 81.3%. EBV-positive and EBV-negative plasmacytomas possessed similar clinicopathologic features, except more frequent cytologic atypia, bone involvement and MYC aberrations in the former group. The survival rate of patients with EBV-positive plasmacytoma was comparable to that of patients with EBV-negative plasmacytoma. In comparison to PBL, EBV-positive plasmacytoma is less commonly associated with a "starry-sky" appearance, necrosis, absence of light chain expression, and a high Ki67 index (>75%). The most recurrently mutated genes/signaling pathways in EBV-positive plasmacytoma are epigenetic regulators, MAPK pathway, and DNA damage response, while the most frequently reported mutations in PBL are not observed. Collectively, EBV-positive plasmacytoma should be regarded as a biological variant of plasmacytoma. Thorough morphologic examination remains the cornerstone for distinguishing EBV-positive plasmacytoma and PBL, and molecular studies can be a valuable complementary tool.

Synchronous clear cell renal cell carcinoma and clonal plasmacytoid cell infiltration: A case report and literature review

Recent studies of tumor microenvironments have revealed that clonal B cells reacting to tumor-derived antigens play an important role in anti-tumor immunity. We report a case of a 72-year-old Japanese man with a complaint of fever for 1 month. Computed tomography revealed a 48 mm mass in his right kidney. The patient underwent a right nephrectomy and histology revealed clear cell renal cell carcinoma (ccRCC) of Fuhrman Grade 4 with rhabdoid morphology. Focally, marked plasmacytoid cell infiltration was detected in the carcinoma. These plasmacytoid cells were immunohistochemically positive for immunoglobulin (Ig) G, and kappa light chain restriction was confirmed using mRNA in situ hybridization. Programmed death-ligand 1 (PD-L1) immunostaining and RNA in situ hybridization of transforming growth factor beta (TGF-β) revealed that both PD-L1 and TGF-β were highly expressed in the area with clonal plasmacytoid cell infiltration. The patient developed bone metastasis 3 months after surgery, and plasmacytoma was not detected during the observation period. We identified a potential link between an immunosuppressive microenvironment and clonal B cell proliferation. The latter posed a differential diagnosis problem between reactive and neoplastic clonal B cell proliferation vis-à-vis a plasmacytoma complicating carcinoma.

Concurrent chronic lymphocytic leukemia/small lymphocytic lymphoma and hairy cell leukemia: clinical, pathologic and molecular features

Simultaneous occurrence of hairy cell leukemia (HCL) and chronic lymphocytic leukemia/small lymphocytic lymphoma (termed CLL) is very rare. Clinical characteristics, pathology and management of these cases have not been well described. We present six patients with CLL and HCL or HCL variant (HCL-v). Of six patients, three were initially diagnosed with CLL and later developed concurrent HCL. Two patients had concurrent HCL or HCL-v and CLL at initial diagnosis. One had HCL first, followed by concurrent CLL. Polymerase chain reaction analysis demonstrated B-cell clonality in all cases, with two distinct clonal populations in four cases, and three clonal populations in one case. Five patients were treated with a combination of a purine analog such as fludarabine, cladribine, and pentostastin with either rituximab or ibrutinib, while one received dabrefenib and trametinib. All patients achieved a durable response to either CLL or HCL-directed therapy with reduction or ablation of coexisting B-cell clones.

Expansion of PD1-positive T Cells in Nodal Marginal Zone Lymphoma: A Potential Diagnostic Pitfall

The diagnosis of nodal marginal zone lymphoma (NMZL) can be challenging, with the differential diagnosis including other low-grade B-cell lymphomas, reactive hyperplasia, and even some cases of peripheral T-cell lymphoma (PTCL). PTCL may have a perifollicular growth pattern mimicking NMZL. We and others have noted an atypical distribution of T-follicular helper (TFH) cells in some cases of NMZL. This study was prompted by the diagnosis of NMZL in several cases in which a marked increase of TFH cells, as determined by staining for programmed death-1 (PD1), had prompted suspicion for a diagnosis of PTCL. We analyzed PD1 staining in 48 cases of NMZL to characterize the extent and pattern of the PD1-positive infiltrate. Three main patterns of PD1 staining were identified: follicular pattern (peripheral, n=16; central, n=9; mixed, n=3), diffuse pattern (n=4), and a reduced or normal staining pattern in residual follicles (n=16). A comprehensive analysis of other TFH markers was undertaken in 14 cases with a high content of PD1-positive cells that were confirmed as B-cell lymphoma by clonality analysis. We describe in detail 5 of these cases in which PTCL was an initial consideration. This study illuminates the diverse immunohistochemical patterns encountered in NMZL and highlights a diagnostic pitfall important for diagnostic accuracy.

Diagnostic Algorithm of Common Mature B-Cell Lymphomas by Immunohistochemistry

CONTEXT

- Different types of mature B-cell lymphomas, including plasma cell neoplasms, exhibit distinct immunohistochemical profiles, which enable them to be correctly diagnosed. However, except for rare examples of lymphoma-specific immunohistochemistry, such as cyclin D1 in mantle cell lymphoma and annexin A1 in hairy cell leukemia, immunohistochemical profiles of mature B-cell lymphomas overlap and lack specificity.

OBJECTIVES

- To systemically review immunohistochemical features associated with commonly encountered mature B-cell lymphomas based on the presence or absence of CD5 and CD10; to review the immunophenotypic profile of plasma cells derived from plasma cell myelomas and B-cell lymphomas; and to review a group of rare, aggressive B-cell lymphomas with antigen expression features of plasma cells.

DATA SOURCES

- Published and PubMed-indexed English literature was reviewed.

CONCLUSIONS

- Although the presence or absence of CD5 and CD10 expression should be included in the initial immunohistochemistry screening panel for mature B-cell lymphomas, appropriate and judicial use of other B-cell antigens is necessary to ensure correct diagnoses. Furthermore, although the status of CD5 and CD10 expression is associated with certain prototypes of B-cell lymphomas, their expression is not specific. Plasma cells from plasma cell neoplasias and B-cell lymphomas exhibit overlapping but relatively distinct immunophenotypes; thus, a panel of immunohistochemical markers (CD19, CD45, CD56, and CD117) can be employed for their proper identification. Lastly, CD138 staining results are almost always positive in a group of aggressive B-cell lymphomas with plasmablastic features, including plasmablastic plasma cell myeloma, plasmablastic lymphoma, and ALK-1⁺ large B-cell lymphoma.

Unusual course of generalized lymph node primary plasmacytoma in a patient with Sjögren's syndrome: a case report

BACKGROUND

Primary lymph node plasmacytoma is a rare disease that typically involves lymph nodes of the neck. In only 15% of cases is the disease generalized. Here, we present a case of generalized lymph node plasmacytoma in a patient with Sjögren's syndrome with an unusual course.

CASE PRESENTATION

A 48-year-old white woman presented to our hospital with enlargement of groups of lymph nodes, liver, and spleen. Her medical history was consistent with a 12-year course of Sjögren's syndrome. Blood and urine immunochemistry showed a massive (72 g/l) M-gradient formed from immunoglobulin Aκ in the serum and monoclonal free κ-type light chains in her urine. A skeletal X-ray revealed no bone destruction. Cytological and histological bone marrow assays showed no signs of plasma cell infiltration. The microarchitecture of her neck and inguinal lymph nodes was destroyed. Only small remnants of B cell follicles were found, while the interfollicular areas were expanded and infiltrated by CD138, MuM1, CD43, and IgAκ-positive plasma cells. After nine cycles of doxorubicin, cyclophosphamide, vincristine, and prednisolone chemotherapy, complete remission was achieved. However, the lymphoma relapsed 3 months later, with histological verification in her femoral lymph node. Despite the absence of subsequent adequate therapy, she gradually achieved complete remission of plasmacytoma with the disappearance of paraproteins.

CONCLUSIONS

Currently, primary lymph node plasmacytoma is generally considered a nodal marginal zone lymphoma with an extensive plasmacytic differentiation. In our case, despite the critical histological and immunohistochemical evaluation of three lymph node biopsies from different anatomical areas at different times, no signs of nodal marginal zone lymphoma were found. An 18-year follow-up of our patient with primary lymph node plasmacytoma demonstrated an extremely unusual clinical course. Initially, primary lymph node plasmacytoma was refractory to chemotherapy. However, subsequently, she underwent a complete spontaneous remission of plasmacytoma.

Remarkable Response to Methylprednisolone in a Multiple Myeloma Patient with Nodal Disease Refractory to High-Dose Chemotherapy

Multiple myeloma is a disorder of malignant plasma cells, which is characterized by paraprotein production, lytic bone lesions, hypercalcemia, susceptibility to infections, and renal impairment. Here, we describe a patient with IgA myeloma with extensive nodal involvement who obtained significant benefit from high-dose methylprednisolone after failing aggressive induction chemotherapy and high-dose melphalan with autologous stem cell support.

Loss-of-function of the protein kinase C δ (PKCδ) causes a B-cell lymphoproliferative syndrome in humans

Defective lymphocyte apoptosis results in chronic lymphadenopathy and/or splenomegaly associated with autoimmune phenomena. The prototype for human apoptosis disorders is the autoimmune lymphoproliferative syndrome (ALPS), which is caused by mutations in the FAS apoptotic pathway. Recently, patients with an ALPS-like disease called RAS-associated autoimmune leukoproliferative disorder, in which somatic mutations in NRAS or KRAS are found, also were described. Despite this progress, many patients with ALPS-like disease remain undefined genetically. We identified a homozygous, loss-of-function mutation in PRKCD (PKCδ) in a patient who presented with chronic lymphadenopathy, splenomegaly, autoantibodies, elevated immunoglobulins and natural killer dysfunction associated with chronic, low-grade Epstein-Barr virus infection. This mutation markedly decreased protein expression and resulted in ex vivo B-cell hyperproliferation, a phenotype similar to that of the PKCδ knockout mouse. Lymph nodes showed intense follicular hyperplasia, also mirroring the mouse model. Immunophenotyping of circulating lymphocytes demonstrated expansion of CD5+CD20+ B cells. Knockdown of PKCδ in normal mononuclear cells recapitulated the B-cell hyperproliferative phenotype in vitro. Reconstitution of PKCδ in patient-derived EBV-transformed B-cell lines partially restored phorbol-12-myristate-13-acetate-induced cell death. In summary, homozygous PRKCD mutation results in B-cell hyperproliferation and defective apoptosis with consequent lymphocyte accumulation and autoantibody production in humans, and disrupts natural killer cell function.

Follicular lymphomas in children and young adults: a comparison of the pediatric variant with usual follicular lymphoma

Follicular lymphoma (FL), a common lymphoma in adults, occurs rarely in pediatric and young adult patients. Most pediatric cases have been described as grade 3, but the criteria to distinguish the pediatric variant of FL (PFL) from usual FL (UFL) seen in adults are not well defined. We undertook a study of FL in patients under the age of 30. We identified 63 cases, which were analyzed by morphology, immunohistochemistry, and polymerase chain reaction analysis of IGH@ and IGK@ clonality. These data were correlated with clinical findings including stage, treatment, and outcome. Among the 63 cases, 34 cases were classified as PFL: 22 presenting in lymph nodes, 8 in the Waldeyer ring, and 4 in the testis. Clonal immunoglobulin gene rearrangement was detected in 97% of PFL cases, but fluorescence in situ hybridization analysis showed an absence of the BCL2/IGH@ translocation in all cases tested. Twenty-nine cases were classified as UFL, 28 of which presented in lymph nodes. The nodal PFLs were observed exclusively in male patients in both children and young adults with a median age of 15 years. They showed marked head/neck predilection, blastoid cytologic features with a high proliferation rate, lack of BCL2 protein and t(14;18), low clinical stage at presentation, and good prognosis. PFLs involving the Waldeyer ring were distinguished by MUM1 expression, 50% (3/6) of which carried IRF4 breaks. BCL2 expression was common (63%) in the absence of BCL2/IGH@ translocation. UFLs were more common in female patients, exclusively in young adults (median age, 24 y), with no cases reported in patients under the age of 18. Twenty-five of 29 cases were of grade 1-2, and 4 cases were classified as grade 3A. They exhibited a higher clinical stage at presentation. Eighty-three percent expressed BCL2. Our results indicate that histologic and immunophenotypic criteria can reliably separate PFL and UFL and that UFL is exceptionally rare in the pediatric age group. PFL associated with particular anatomic sites have distinctive features and should be evaluated separately in future clinical and biological studies.

[B-cell neoplasms with plasmacellular and plasmablastic differentiation]

Plasma cell malignancies are tumors of terminally differentiated B-cells in which the neoplastic plasma cells are the dominant and proliferating tumor cell component. Plasma cell myeloma (PCM) is one of the most common hematological neoplasms and typically does not cause diagnostic problems. A morphologically and immunophenotypically detectable plasmacellular orplasmablastic differentiation is, however, commonly observed in a wide range of mature B-cell lymphomas. A confident separation of the distinct entities requires the integration of clinical and morphological findings as well as an adequate phenotyping of both the plasma cell and the B-cell component if present. Detection of lymphotropic viruses, specific translocations and novel molecular markers, such as the MYD88 L265P mutation occurring in the vast majority of lymphoplasmacytic lymphomas complement our diagnostic repertoire. In this review we describe the most commonly observed diagnostic problems in separating small B-cell lymphomas from PCM and high-grade B-cell non-Hodgkin lymphoma (B-NHL) with plasmablastic differentiation from extramedullary spread of aggressive PCM and provide helpful criteria for routine diagnostics.

Primary submucosal nodular plasmacytoma of the stomach: a poorly recognized variant of gastric lymphoma

Abstract

Gastric plasmacytoma (GP) is a rare variant of gastric lymphomas. In the exceptional event that a patient presents with GP, the lesion occupies the mucosal layer in the vast majority of cases. Here we report a case of nodular plasmacytoma confined to the submucosa with no evidence of Helicobacter pylori (Hp) infection. The patient was a 59-year old female presenting with no particular symptoms. The tumor was well-demarcated and consisted of a diffuse monomorphic proliferation of plasma cells with numerous lymphoid follicles scattered throughout the tumor. The mucosal surface was intact and not associated with any tumor nodules. The cells were diffusely positive for CD79a, Bob1, EMA and IgA and consistently negative for CD3, CD19, CD20, PAX5, CD56, IgM and IgG. Additionally, in situ hybridization demonstrated clonality in the form of λ light-chain restriction. This submucosal nodular proliferation pattern of plasmacytoma is poorly recognized and considered to be a novel variant of lymphoma.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/3489998708673079

Nodal involvement by cutaneous CD30-positive T-cell lymphoma mimicking classical Hodgkin lymphoma

An association between classical Hodgkin lymphoma (cHL) and mycosis fungoides (MF) or lymphomatoid papulosis has been reported in the literature. However, there can be considerable morphologic and immunophenotypic overlap between cHL and nodal involvement by CD30-positive T-cell lymphoproliferative disorders (CD30-T-LPD). To examine this potential association, biopsies from patients with a history of MF or primary cutaneous CD30-T-LPD and lymph node biopsies reported as either CD30-positive T-cell lymphoma (TCL) with Hodgkin-like cells or cHL were retrieved from the authors' institution. Of 11 cases identified, 10 were considered CD30-positive TCL with Hodgkin-like cells, whereas 1 was confirmed as cHL upon review. Five cases originally diagnosed as cHL were revised as CD30-positive TCL. Cases of CD30-positive TCL with Hodgkin-like cells showed a male predominance (M:F, 4:1) with a median age of 53 years (range, 44 to 72 y). Nearly all patients (9/10) initially presented with skin lesions. In 7/10 patients the draining lymph node was involved, whereas in 3 cases this could not be confirmed. Tumor cells morphologically resembled Hodgkin/Reed-Sternberg cells; they were uniformly strongly positive for CD30, and CD15 was expressed in 9/10 (90%) cases. A T-cell derivation was confirmed by T-cell antigen expression (7/10) and clonal rearrangement of T-cell receptor genes (9/10). In 3 cases a common T-cell clone was identified in skin and lymph node. B-cell markers (CD20/PAX5) were consistently negative. In 1 case the diagnosis of cHL followed by lymphomatoid papulosis was confirmed, with Hodgkin/Reed-Sternberg cells expressing PAX5, CD30, and CD15. In situ hybridization studies for Epstein Barr virus were negative. We show that cHL is less often associated with MF and primary cutaneous CD30-T-LPD than previously thought and that the coexpression of CD30 and CD15 in these TCLs may lead to a mistaken diagnosis of cHL.

Plasma cell myeloma associated with Epstein-Barr virus infection in an 11-year-old girl

Multiple myeloma is extremely rare in children and represents fewer than 1% of all patients with myeloma. We report a case of multiple myeloma in an 11-year-old girl, who presented with a well-differentiated immunoglobulin A/kappa plasmacytoma at the base of the skull at 9 years of age; at that time, the bone marrow biopsy was negative. Two years later, the patient experienced generalized bone pain with multiple lytic bone lesions that affected the skull, long bones, ribs, and clavicle. The bone marrow biopsy showed a well-differentiated (Marschalko-type) multiple myeloma that was positive for CD138 and immunoglobulin A, with kappa light chain restriction. Interestingly, the Epstein-Barr virus (EBV) was detected by in situ hybridization for EBV-encoded RNA (EBER) in the majority of the neoplastic cells from both biopsy specimens. The patient responded favorably to treatment with dexamethasone, thalidomide, and zoledronic acid and is scheduled for bone marrow transplantation.

Early lesions in lymphoid neoplasia: Conclusions based on the Workshop of the XV. Meeting of the European Association of Hematopathology and the Society of Hematopathology, in Uppsala, Sweden

The increasing use of immunophenotypic and molecular techniques on lymphoid tissue samples without obvious involvement by malignant lymphoma has resulted in the increased detection of "early" lymphoid proliferations, which show some, but not all the criteria necessary for a diagnosis of malignant lymphoma. In most instances, these are incidental findings in asymptomatic individuals, and their biological behaviour is uncertain. In order to better characterize these premalignant conditions and to establish diagnostic criteria, a joint workshop of the European Association for Haematopathology and the Society of Hematopathology was held in Uppsala, Sweden, in September 2010. The panel reviewed and discussed more than 130 submitted cases and reached consensus diagnoses. Cases representing the nodal equivalent of monoclonal B-cell lymphocytosis (MBL) were discussed, as well as the "in situ" counterparts of follicular lymphoma (FL) and mantle cell lymphoma (MCL), topics that also stimulated discussions concerning the best terminology for these lesions. The workshop also addressed the borderland between reactive hyperplasia, and clonal proliferations such as pediatric marginal zone lymphoma and pediatric FL, which may have very limited capacity for progression. Virus-driven lymphoproliferations in the grey zone between reactive lesions and manifest malignant lymphoma were covered. Finally, early manifestations of T-cell lymphoma, both nodal and extranodal, and their mimics were addressed. This workshop report summarizes the most important conclusions concerning diagnostic features, as well as proposals for terminology and classification of early lymphoproliferations and tries to give some practical guidelines for diagnosis and reporting.

Fever of unknown origin (FUO) attributable to indolent lymphoproliferative disorder due to a plasmacytoma expressing immunoglobulin A

BACKGROUND

The most common categories causing fevers of unknown origin (FUOs) include infective rheumatic/inflammatory disorders and malignancies. Among neoplastic causes of FUOs, lymphomas, hepatomas, renal hypo-nephromas, and hepatomas are the most common. Other malignancies rarely present with FUOs (eg, multiple myeloma).

CASE REPORT

We describe a 58-year-old man who presented with an FUO accompanied by night sweats, weight loss, and a groin mass. A biopsy of the groin mass (ie, his lymph node) was negative for infectious diseases, rheumatic or inflammatory diseases, and malignancies. Histochemical and immunological studies of the lymph node showed it to contain a plasmacytoma expressing immunoglobulin A (IgA). An immunohistochemical study of the plasma-cell infiltrate demonstrated strong CD138 staining. A bone marrow biopsy was negative for multiple myeloma.

CONCLUSION

We believe this is the first reported rare case of an indolent, lymphoproliferative disorder attributable to an IgA-secreting plasmacytoma presenting as an FUO.

Synchronous indolent primary gastrointestinal lymphomas managed successfully with conservative measures

We report the case of a 65-year-old man who presented with epigastric pain and guaic-positive stool. Upper and lower endoscopy revealed abnormalities in the gastric antrum and terminal ileum. Biopsy of these sites revealed histologically and immunophenotypically distinct lymphomas: gastric extranodal marginal zone lymphoma in the background of Helicobacter pylori infection and follicular lymphoma of the terminal ileum. After treatment with an H. pylori eradication regimen, repeat endoscopy showed resolution of the gastric extranodal marginal zone lymphoma and persistence of the ileal follicular lymphoma. Interestingly, molecular studies performed on the biopsy specimens revealed a common IgH rearrangement, suggesting a common precursor cell responsible for these two malignant processes. We present this unique case with a review of the literature, highlighting treatment principles for these two subtypes of indolent gastrointestinal non-Hodgkin lymphoma.

Coexisting and clonally identical classic hodgkin lymphoma and nodular lymphocyte predominant hodgkin lymphoma

We report a case of concurrent nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) and classic Hodgkin lymphoma (cHL), of nodular sclerosis subtype, in an otherwise healthy 24-year-old man with a strong family history of cHL. The patient was found to have a parotid mass, which was diagnosed as NLPHL, and a thymic mass diagnosed as cHL, of nodular sclerosis subtype concurrently. The lesion in the parotid showed features typical of NLPHL by morphology and immunophenotype. The LP cells were positive for PAX5, CD20, Oct2, weakly positive for CD30, and negative for CD15. The thymic lesion, diagnosed as cHL, of nodular sclerosis subtype, showed prominent bands of fibrosis and Hodgkin/Reed-Sternberg and lacunar cells positive for CD30 and CD15. These cells were variably positive for CD20 and negative for Oct2. PAX5 was weakly positive. Immunoglobulin gene rearrangement studies by polymerase chain reaction were carried out on microdissected Hodgkin/Reed-Sternberg and LP cells, which were shown to have identically sized peaks. NLPHL and cHL are 2 distinct diseases and are almost never seen concurrently. We present a case in which polymerase chain reaction analysis indicated that the tumor cells of these 2 distinct entities were clonally identical.