Monotypic Plasma Cell Proliferation of Uncertain Clinical Significance Mimicking Interstitial Cystitis: An Early Lesion of MALT Lymphoma?

We prospectively studied our institutional experience of bladder extranodal marginal zone (mucosa-associated lymphoid tissue [MALT]) lymphoma including bladder biopsies in which the possibility of MALT lymphoma was considered. We identified a subset of cases primary to the urinary bladder, presenting with prominent plasma cell infiltrates and symptoms mimicking bladder pain syndrome/interstitial cystitis. These proliferations were designated for this study as "monotypic plasma cell proliferation of uncertain clinical significance" (MPCP-US), as the features were insufficient for diagnosis of MALT lymphoma. We identified 33 patients, consisting of 22 cases of MPCP-US (6 of which were associated with amyloid deposition) and 11 cases of MALT lymphoma. MPCP-US was more prevalent in men (73%), a mass lesion was not identified at cystoscopy, and only 1 case had an accompanying urinary tract infection (4.5%). Histologically, MPCP-US presented as monotypic plasma cells arranged in a superficial band-like distribution in the lamina propria, predominantly kappa restricted (68%) and IgA+ or IgM+ (64% and 23%, respectively) and without a histologic mass of atypical B cells or plasma cells, not diagnostic for established MALT lymphoma or plasmacytoma. Secondary involvement of the bladder by other lymphoproliferative disorders was excluded and there was no evidence of progressive disease. MALT lymphomas are presented for comparison and our analysis demonstrated that MPCP-US represent a different clinicopathologic entity compared with classic MALT lymphoma. We present the first series of cases of MPCP-US. The recognition of this entity is fundamental to the development of management protocols to relieve intractable symptoms mimicking bladder pain syndrome/interstitial cystitis in these patients.

[Clinicopathologic features of primary hepatic marginal zone lymphoma of mucosa-associated lymphoid tissue and hepatic pseudolymphoma].

Objective: To study the clinicopathological features of primary hepatic extranodal marginal zone lymphoma of mucosa associated lymphoid tissue (MALT lymphoma) and hepatic pseudolymphoma, and to discuss their differential diagnosis, treatment and prognosis. Methods: Three primary hepatic MALT lymphomas and two hepatic pseudolymphomas collected from January 2012 to March 2017 in the First Affiliated Hospital of Nanjing Medical University were evaluated by HE and immunohistochemistry(IHC), in-situ hybridization and immunoglobulin (Ig) gene rearrangement detection, and the relevant literature reviewed. Results: In the three MALT lymphomas, tumor cells infiltrated the portal areas with nodular pattern, and invaded the surrounding normal liver with serpiginous configuration and formation of confluent sheets. A number of bile ducts were entrapped within the lesions, and showed lymphoepithelial lesion. Reactive lymphoid follicles were present and surrounded by tumor cells, consisting of predominantly centrocyte-like cells and monocytoid B cells. There were clusters of epithelioid histiocytes in one case. The tumor cells were positive for CD20, PAX5 and negative for CD5, CD23, CD10, bcl-6, and cyclin D1. In the two hepatic pseudolymphomas, the lesions presented as solitary nodules well-demarcated from the surrounding liver tissue; one case was partially encapsulated with fibrous tissue. Entrapped bile ducts were only found at the edge of the lesions without lymphoepithelial lesion. The lesions comprised of massive lymphoid proliferation consisting predominantly of reactive lymphoid follicles, but not monocytoid B-cells or atypical cells. By IHC, a mixture of B- and T-cell population was identified. A monoclonal rearrangement of the Ig gene was detected in all three MALT lymphomas but not in two pseudolymphomas. Interphase fluorescence in situ hybridiazation test for MALT1 break-apart gene was positive in two cases of MALT lymphomas and EBER was negative in all studied cases. Conclusions: Primary heptic MALT lymphoma and pseudolymphoma are both rare lymphoid proliferative lesions of liver. These two lesions have overlapping histological and IHC features and are top differential diagnosis to each other. A combination analysis of morphology, immunophenotype and Ig gene rearrangement is helpful to distinguish between them.

Immunohistochemical analysis of the novel marginal zone B-cell marker IRTA1 in malignant lymphoma.

Marginal zone lymphoma (MZL) is a low-grade B-cell lymphoma derived from marginal zone B cells. Because of a lack of specific immunohistochemical markers, MZL is mainly diagnosed based on the cytological appearance and growth pattern of the tumor. Marginal zone B cells were recently shown to selectively express immunoglobulin superfamily receptor translocation-associated 1 (IRTA1), but the antibody used in that study is not commercially available. We therefore investigated the IRTA1 expression in nonneoplastic lymphoid tissues and 261 malignant lymphomas, examining the ability of a commercially available antibody to accurately diagnose MZL. Among 37 MZLs, 23 of 25 extranodal MZLs of mucosa-associated lymphoid tissue (MALT lymphomas), 3 of 6 splenic MZLs and 3 of 6 nodal MZLs were positive for IRTA1. Among the 98 diffuse large B-cell lymphomas, 33 were positive for IRTA1, including 1 of 38 follicular lymphomas, and all precursor B-lymphoblastic (2/2) and T-lymphoblastic (7/7) leukemia/lymphomas. Other mature B-cell and T-cell lymphomas, and Hodgkin lymphoma were negative for IRTA1. In MALT lymphoma, positive cells were detected mainly in intraepithelial and subepithelial marginal zone B cells. In 1 case of grade 3 follicular lymphoma, IRTA1 was also expressed in the area of large cell transformation. When tumors were classified as germinal center B cell-like (GCB) or non-GCB using the algorithm of Hans, positive expression of IRTA1 was correlated significantly with non-GCB diffuse large B-cell lymphomas (P < .05). These results demonstrated the ability of the commercially available IRTA1 antibody to distinguish MALT lymphoma from other low-grade B-cell lymphomas.

Ileal mucosa-associated lymphoid tissue lymphoma presenting with small bowel obstruction: a case report.

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT Lymphoma) of the gastrointestinal tract commonly involves the stomach in the setting of concurrent Helicobacter pylori (H. pylori) infection. Primary ileal MALT lymphoma is rare, and has not been associated with a specific infectious disease. We report a case of a 58-year-old man who presented to the emergency department with constipation and abdominal distension, and signs of an obstructing mass on computed tomography scan. A small bowel resection was performed which revealed an 8 cm saccular dilatation with thickened bowel wall and subjacent thickened tan-yellow tissue extending into the mesentery. Histologically, there was a diffuse lymphoid infiltrate consisting of small atypical cells with monocytoid features. These cells were CD20-positive B-lymphocytes that co-expressed BCL-2 and were negative for CD5, CD10, CD43, and cyclin D1 on immunohistochemical studies. Kappa-restricted plasma cells were also identified by in situ hybridization. The overall proliferation index was low with Ki-67 immunoreactivity in approximately 10 % of cells. No areas suspicious for large cell or high grade transformation were identified. The pathologic findings were diagnostic of an extranodal marginal zone lymphoma involving the ileum, with early involvement of mesenteric lymph nodes. Small hypermetabolic right mesenteric and bilateral hilar lymph nodes were identified by imaging. The bone marrow biopsy showed no evidence of involvement by lymphoma. The patient was clinically considered advanced stage and opted for therapy with rituximab infusions. After six months of therapy, follow-up radiologic studies demonstrated significant decrease in size of the mesenteric lymph nodes.

Rare presentation of secondary cutaneous involvement by splenic marginal zone lymphoma: report of a case and review of the literature.

Cutaneous lymphomas encompass a broad spectrum of malignancies, including both primary and secondary cutaneous lymphomas. Determining the exact subtype of cutaneous lymphoma offers prognostic importance and directs therapeutic decisions. We describe the case of a 67-year-old woman with cutaneous involvement of splenic marginal zone lymphoma successfully treated with rituximab and bendamustine. We discuss the diagnostic work-up, including the histopathologic findings and treatment of this disease.

Spontaneous regression of primary extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) colliding with invasive ductal carcinoma of the breast: a case report.

Malignant lymphomas of the breast, whether they are primary or secondary, are rare diseases, constituting only around 0.1 to 0.15% of the primary neoplasm of the breast. Although the most prevalent histological subtype is diffuse large B-cell lymphoma, primary extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) also occurs in the breast as in other extranodal sites, comprising about 15% of malignant lymphomas of the breast. In many cases, primary MALT lymphoma of the breast is low grade lymphoma, localized in the breast with indolent behavior and good prognosis. Here we report a case of spontaneous regression of primary MALT lymphoma of the breast. The lymphoma collided with invasive ductal carcinoma in the breast. Both tumors were identified in the Vacora biopsy specimen before the operation. However, the lymphoma disappeared, while the carcinoma remained, in the resected mass. To our knowledge, this is the first case report of spontaneous regression of MALT lymphoma of the breast colliding with breast cancer.

Follicular lymphoma mimicking marginal zone lymphoma in lymph node: a case report.

Nodal follicular lymphoma (FL) is typically composed of follicular or nodular proliferation of small cleaved lymphoid cells, presumably derived from germinal center (GC) B cells. The hallmark of FL is t(14;18)(q32;q21) chromosomal translocation, which juxtaposes anti-apoptotic gene BCL2 to immunoglobulin heavy chain (IGH) promoter. Reflecting this background, FL cells are immunohistochemically positive for BCL2 as well as GC B cell markers CD10 and BCL6. It is known that low grade B-cell lymphomas, including FL, chronic lymphocytic leukemia/small lymphocytic lymphoma, and marginal zone lymphoma, are sometimes associated with marginal zone differentiation or plasmacytic differentiation. The marginal zone differentiation obscures the morphological differences among these, providing diagnostic challenges for histopathologists. In this paper, we present a case of FL, originally mimicking marginal zone lymphoma in the axillary lymph node. Subsequent bone marrow biopsy showed paratrabecular infiltration of small to medium-sized lymphoid cells. Immunohistochemical analysis of the bone marrow biopsy together with histopathology and flow cytometry of the axillary lymph node led to a final diagnosis of FL with marginal zone differentiation in the axillary lymph node and its bone marrow infiltration. Our case illustrates and reconfirms the importance of clinicopathological correlation which leads to a correct diagnosis.

C-MYC overexpression predicts aggressive transformation and a poor outcome in mucosa-associated lymphoid tissue lymphomas.

Mucosa-associated lymphoid tissue (MALT) lymphoma is a relatively common, indolent B-cell lymphoma. MALT lymphoma with large tumor cells (LTCs) is believed to have the potential to transform to aggressive diffuse large B-cell lymphoma (DLBCL) which may have a poor prognosis. C-MYC is a transcription factor. Its translocation and overexpression predicts an inferior prognosis and poor response to therapy in cases of DLBCL. In the current study, C-MYC expression was detected in MALT lymphomas, and its relationship to the occurrence of LTCs, clinicopathological parameters and prognosis was assessed. A total of 69 cases were enrolled in the study, including 42 cases of MALT lymphoma without LTCs, 20 cases of MALT lymphoma with LTCs and 7 cases of DLBCL with a MALT lymphoma component (DLBCL+MALT). Immunohistochemistry and fluorescent in situ hybridization analyses were performed. In total, 15/42 (35.7%) cases were nuclear positive for C-MYC expression in the group without LTCs, whereas 15/20 (75.0%) and 4/7 (57.1%) cases were positive in the group with LTCs and in the group with DLBCL+MALT, respectively (P=0.004). Univariate and multivariate analysis were used to determine the correlations of C-MYC expression and clinicopathological parameters with overall survival (OS). C-MYC expression, Ann Arbor stage, LDH level and IPI were considerably associated with OS according to the univariate analysis. However, only C-MYC expression ≥ 20% showed a statistical significance in the multivariate analysis (HR=20.604, 95% CI: 1.909-222.412, P=0.013). Therefore, C-MYC overexpression may play an important role in aggressive transformation and is an independent prognostic factor in MALT lymphoma.

Extranodal marginal zone lymphoma from ocular adnexae with subcutaneous involvement.

Extranodal marginal zone lymphoma (MZL) of mucosa-associated lymphoid tissue usually originates from cutaneous or mucosal surfaces. A rare site of involvement is the subcutaneous tissue of any location. Here, we describe a 58-year-old man who presented with bilateral extranodal MZL of mucosa-associated lymphoid tissue from ocular adnexae that involved subcutaneous tissue and subsequently extended to multiple anatomical locations in the head and neck, upper back, and arm. The neoplastic cells expressed B-cell markers, and the plasma cells expressed IgG4. The unusual pattern of infiltration of this extranodal MZL and the possible significance of IgG4 expression in this case are discussed.

Primary cutaneous marginal zone lymphoma in children: a report of 3 cases and review of the literature.

: Primary cutaneous marginal zone lymphoma (PCMZL) is one of the most common cutaneous B-cell lymphomas. It affects mostly patients in their fourth decade and manifests with multifocal nodules mostly on the arms and upper trunk in more than half of the patients. PCMZL is, however, rare in children and adolescents, with only 20 cases reported in patients aged 20 and younger. The authors present 3 cases of PCMZL in teenagers. The patients were 2 girls aged 18 and 13 and a 17-year-old boy. Two patients presented with multiple lesions involving various anatomic sites, whereas in 1 patient, 2 small closely opposed papules on the abdomen were seen. Histopathologically, the characteristic appearance of PCMZL was found in 3 of 4 specimens, with nodular infiltrates composed of small lymphocytes in the interfollicular compartment, reactive germinal centers, and plasma cells in small clusters mainly at the periphery of the infiltrates, whereas 1 specimen showed a dense lymphocytic infiltrate with small granulomas. Clonality was demonstrated by monotypic immunoglobulin light chain expression and/or monoclonal rearrangement of the immunoglobulin heavy chain genes. No Borrelia burgdorferi was identified on serology or by polymerase chain reaction in any of the cases. Treatment included excision or administration of antibiotics with complete remission in all the 3 patients indicating that PCMZL in children and young adolescents follows the same indolent course with a tendency for recurrences, but excellent prognosis as in adults. The pertinent literature on PCZL in childhood and adolescence is reviewed.

Colonic mucosa-associated lymphoid tissue lymphoma identified by chromoendoscopy.

Colonic mucosa-associated lymphoid tissue (MALT) lymphomas are a rare occurrence and the definitive treatment has not been established. Solitary or multiple, elevated or polypoid lesions are the usual appearances of MALT lymphoma in the large intestine and sometimes the surface may reveal abnormal vascularity. Herein, we report a case of MALT lymphoma and review the relevant literature. Upon colonoscopy, a suspected pathologic lesion was observed in the proximal transverse colon. The lesion could be distinguished more prominently after using narrow-band imaging mode and indigo carmine-dye spraying chromoendoscopy. Histopathologic examination of this biopsy specimen revealed lymphoepithelial lesions with diffuse proliferation of atypical lymphoid cells effacing the glandular architecture and centrocyte-like cells infiltrating the lamina propria. Immunohistochemical analyses showed that tumor cells were positive for CD20 and Bcl-2e, and negative for CD10, CD23, and Bcl-6. According to Ann-Arbor staging system, the patient had stage IIE. A partial colectomy with dissection of the paracolic lymph nodes was performed. Until now, there is no recurrence of lymphoma at follow-up.

Diffuse large B-cell lymphoma of the uterus suspected of having transformed from a marginal zone B-cell lymphoma harboring trisomy 18: a case report and review of the literature.

The patient was a 72-year-old female with the chief complaint of abdominal fullness. A giant primary myoma of the uterine cervix was suspected, and total hysterectomy was performed. Based on a postoperative histopathological examination of the tumor a diagnosis of diffuse large B-cell lymphoma (DLBCL) was made in the uterus and a mass in the greater omentum was diagnosed as a marginal zone B-cell lymphoma (MZBCL). No flow-cytometry studies or chromosome or gene examinations were performed on a fresh specimen. The results of an examination of a paraffin block histopathology specimen by fluorescence in-situ hybridization (FISH) showed no mucosa associated lymphoid tissue lymphoma translocation gene 1 (MALT1) (18q21.1), B-cell lymphoma 2 (BCL2) (18q21.3), or BCL6 (3q27) split signals in either the uterus or the greater omentum, however, trisomy 18 was detected in approximately 50%-70% of the tumor cells in both the uterus and the greater omentum. Trisomy 18 was present in around 15-33% of the DLBCL cells and MZBCL cells. These findings suggested a strong possibility that the tumor cells in the uterus and greater omentum were the same clone and that transformation from MZBCL to DLBCL had occurred. Since DLBCLs that result from a transformation usually have a worse outcome than de novo DLBCLs, even when a DLBCL seems to have originated in the uterus the surrounding tissue should always be examined, and caution should be exercised in regard to transformation from a low-grade B-cell lymphoma to a DLBCL.