Gabriela Gualco

Clinicopathologic and molecular features of 122 Brazilian cases of nodal and extranodal NK/T-cell lymphoma, nasal type, with EBV subtyping analysis

Extranodal natural killer/T-cell lymphoma, nasal type (NK/TCL) is more prevalent in Asia and in some areas of South and Central America, but it is rarely seen in the United States and Europe. In this study, a series of 122 cases of NK/TCL from Brazil was analyzed with respect to clinicopathologic features. Clinical characteristics and geographic distribution were evaluated in 97 cases of nasal/nasopharyngeal region and 23 cases in extranasal sites including 6 nodal cases. Clinical staging and follow-up information was available in a subset of 21 patients. All cases harbored Epstein-Barr virus (EBV), 95% and 85% expressed cytoplasmic CD3 and CD56, respectively, and all cases were positive for at least 1 marker for cytotoxic granules. The global distribution of EBV subtypes showed predominance of strain subtype A, 89%, and subtype B, 11%. No dual infections were detected. TCR-&ggr; TCR-gene rearrangement was observed in 7 cases; all of them extranodal. Three of TCR-&ggr;+ cases showed EBV subtype A. Two TCR-&ggr;+/CD56+ cases showed EBV subtype B. Geographic distribution of NK/TCL showed higher frequency in the southeast and northeast regions of Brazil. Striking differences among geographic regions were seen with the vast majority of EBV subtype B (86%) occurring in the south and southeast regions.

MUM1/IRF4: A Review.

MUM1/IRF4 protein is a member of the interferon regulatory factor (IRF) family of transcriptional factors initially described as downstream regulators of interferon signaling. The quantity of this factor varies within the hematopoietic system in a lineage and stage-specific way. It is considered to be a key regulator of several steps in lymphoid, myeloid, and dendritic cell differentiation and maturation. MUM1/IRF4 expression is observed in many lymphoid and myeloid malignancies, and may be a promising target for the treatment of some of these neoplasms. We reviewed the literature on MUM1/IRF4, with emphasis on the pathologic aspects of this marker in reactive and malignant hematologic and nonhematologic conditions.

Primary and Secondary T-cell Lymphomas of the Breast: Clinico-pathologic Features of 11 Cases

Breast involvement by non-Hodgkin lymphomas is rare, and exceptional for T-cell lymphomas; we studied the morphologic, immunophenotypic, and clinical features of 11 patients with T-cell non-Hodgkin lymphomas involving the breast. Four cases fulfilled the definition criteria for primary breast lymphomas, 3 females and 1 male, with a median age of 51 years. One primary breast lymphomas was T-cell lymphoma unspecified, other was subcutaneous panniculitis-like T-cell lymphoma, and 2 cases were anaplastic large cell lymphomas. One of the anaplastic large cell lymphoma cases was found surrounding a silicone breast implant and presented as clinically as mastitis; whereas the other case occurred in a man. T-cell lymphoma secondarily involved the breast in 7 patients, all women and 1 bilateral, with a median age of 29 years. These secondary breast lymphomas occurred as part of widespread nodal or leukemic disease. Three patients had adult T-cell leukemia/lymphoma, including the patient with bilateral lesions, 3 others had precursor T-lymphoblastic lymphoma/leukemia, and the other presented with a peripheral-T-cell lymphoma nonotherwise specified type. Breast T-cell lymphomas are very infrequent and are morphologically and clinically heterogeneous.

B-Cell and T-Cell Lymphomas of the Breast: Clinical—Pathological Features of 53 Cases

Breast involvement by non-Hodgkin lymphomas is rare. We studied the morphological, immunophenotypical, and clinical features of 53 cases of malignant lymphomas involving the breast in a population of Brazilian patients. Most of the cases were of B-cell phenotype. Four of the patients with primary breast lymphomas had T-cell lymphomas, 3 had CD30-positive anaplastic large cell lymphomas, and 1 had panniculitis-like T-cell lymphoma. Most patients presented with an incidental breast mass. Secondary breast lymphoma was seen in 19 patients and most commonly occurred as part of widespread nodal disease. Two patients presented with bilateral breast involvement. The most prevalent histological subtype was also diffuse large B-cell lymphoma, followed by follicular lymphoma. This study shows that the broad morphological and immunophenotypical spectrum of malignant lymphoma of the breast occurring in a large series of Brazilian patients has many similarities with that seen in Western countries, with a higher proportion of high-grade lymphomas in both primary and secondary cases.

BCL6, MUM1, and CD10 expression in mantle cell lymphoma.

Mantle cell lymphoma (MCL) characteristically express CD20, CD5, and cyclin-D1, carries the translocation t(11;14) (q13;q32) and typically has no expression of germinal center cell markers. So-called aberrant phenotypes such as CD5 negative and cyclin-D1-negative MCL have been described. Also few cases with CD10 and/or BCL-6 protein expression have been reported. We analyzed 127 MCL looking for the frequency of aberrant immunophenotype, CD10, BCL-6, and MUM1 expression. All cases were CD20 and cyclin-D1 positive, 96% expressed CD5, and 98% showed the t(11;14). BCL-6 expression was observed in 12% of the cases and MUM1 in 35%. No one case showed CD10 positivity in 30% or more neoplastic cells. Only 3 cases showed 10% to 20% of tumoral cells positive for CD10. MUM1 expression was observed in 67% of the BCL-6 positive cases. Thirty-two percent of the cases showed a MUM1+/BCL-6−/CD10− phenotype and 56% had a triple-negative-pattern. Aberrant phenotype is infrequent but not rare, and does not rule out a diagnosis of MCL in an otherwise typical case.

The spectrum of B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and classical Hodgkin lymphoma: a description of 10 cases.

B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and classical Hodgkin lymphoma, is a diagnostic provisional category in the World Health Organization (WHO) 2008 classification of lymphomas. This category was designed as a measure to accommodate borderline cases that cannot be reliably classified into a single distinct disease entity after all available morphological, immunophenotypical and molecular studies have been performed. Typically, these cases share features intermediate between diffuse large B-cell lymphoma and classical Hodgkin lymphoma, or include characteristics of both lymphomas. The rarity of such cases poses a tremendous challenge to both pathologists and oncologists because its differential diagnosis has direct implications for management strategies. In this study, we present 10 cases of B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and classical Hodgkin lymphoma and have organized the criteria described by the WHO into four patterns along with detailed clinical, morphological and immunophenotypic characterization and outcome data. Our findings show a male preponderance, median age of 37 years and a mediastinal presentation in 80% of cases. All cases expressed at least two markers associated with B-cell lineage and good response to combination chemotherapy currently employed for non-Hodgkin lymphomas.

Nodal diffuse large B-cell lymphomas in children and adolescents: immunohistochemical expression patterns and c-MYC translocation in relation to clinical outcome.

Diffuse large B-cell lymphoma (DLBCL) is a very infrequent neoplasm in the pediatric age group; therefore there are very few studies on the immunophenotype or genetics of these cases. We studied a series of 16 patients with nodal DLBCL occurring in patients between 10 and 18 years of age. The cases were classified according to the 2008 World Health Organization classification criteria, with application of immunohistochemistry for the detection of CD10, BCL-6, and MUM1 proteins to divide the lymphomas into germinal center and nongerminal center types. In addition, TCL1, BCL-2 expression, and the Ki-67 proliferation index were evaluated by immunohistochemistry, and c-MYC and BCL2 translocations were evaluated by fluorescence in situ hybridization. All these parameters were correlated with clinical features and outcome. Our study revealed that centroblastic morphology and the germinal center type of DLBCL are more prevalent in these young patients (63%), with 37% containing a c-MYC translocation. Only 1 case showed a BCL2 translocation, reflecting a double-hit case with features intermediate between DLBCL and Burkitt lymphoma. We found a higher frequency of BCL-2 expression than previously reported, with no direct influence on the outcome of the disease in univariate or multivariate analysis. The expression of TCL1 has not been specifically studied in nodal pediatric DLBCL before; we found a 31% incidence of TCL1 expression. MUM1 expression was observed in 44% of the cases and these positive cases showed a significant negative impact on clinical outcome. TCL1 is directly and significantly associated with the presence of c-MYC and a high proliferative index. The germinal center and nongerminal center subtypes showed significant differences for both overall survival and disease-free interval. c-MYC translocation was found in 37% of patients, and had a favorable impact on clinical outcome. We conclude that nodal pediatric and adolescent DLBCL are mainly of the germinal center type, with a generally good outcome despite the frequent expression of BCL-2 and the presence of c-MYC translocation. TCL1 expression seems to be associated with a good clinical outcome, whereas MUM1 expression predicts a poor clinical outcome.

Frequent Expression of CD99 in Anaplastic Large Cell Lymphoma : A Clinicopathologic and Immunohistochemical Study of 160 Cases

Originally described as a diagnostically useful marker for Ewing sarcoma, CD99 immunoreactivity has also been documented in a variety of other tumors, including hematopoietic neoplasms. By using conventional paraffin immunoperoxidase staining and tissue microarrays, we retrospectively investigated CD99 expression in a series of 160 anaplastic large cell lymphoma (ALCL) cases. Of the 160 cases, 103 (64.4%) were positive for CD99. The distribution of CD99 positivity was similar for nodal (66/103 [64.1%]), extranodal, (21/32 [66%]), and primary cutaneous lesions (16/25 [64%]). CD99 expression was present in 96 (64.4%) of 149 of the common type, 4 (80%) of 5 of the small cell variant, and 3 (50%) of 6 of the lymphohistiocytic variant cases. CD99 expression was slightly more frequent in anaplastic large cell lymphoma kinase (ALK)+ cases compared with ALK- cases (43/54 [80%] vs 44/81 [54%]). With 2 exceptions, ALK+ ALCL was seen only in patients younger than 41 years. We conclude that CD99 is frequently expressed in ALCL, with a slightly increased frequency in the younger age ALK+ cases. Nodal and extranodal ALCL should be considered in the differential diagnosis when a CD99+ neoplasm is encountered.

Frequent expression of multiple myeloma 1/interferon regulatory factor 4 in Burkitt lymphoma

Burkitt lymphoma is a highly aggressive non-Hodgkin lymphoma with endemic, sporadic, and immunodeficiency-associated clinical variants composed of monomorphic medium-sized B cells with a high proliferation rate and a translocation involving the C-MYC locus. Classically, the immunophenotype of Burkitt lymphoma has been considered to be the germinal center type. In most reports, all cases of Burkitt lymphoma are reported to be multiple myeloma 1-negative. multiple myeloma 1 expression is seen in plasma cells and in a small fraction of B cells located in the light zone of germinal centers corresponding to the final step of intra-germinal center B-cell differentiation, and in activated T cells. Therefore, multiple myeloma 1 expression may denote the final step of intra-germinal center B-cell differentiation at the centrocyte stage, as well as the subsequent steps of B-cell maturation toward plasma cells. Unlike most normal germinal center B cells, in which the expression of multiple myeloma 1 and bcl-6 are mutually exclusive, the tumor cells in approximately 50% of multiple myeloma 1-positive DLBCL show coexpression of bcl-6, suggesting that the expression of these proteins may be deregulated. Twenty-five Burkitt lymphoma cases, including 19 associated with HIV, were reported in one of the few studies in the literature; 2 of these cases showed occasional multiple myeloma 1-positive cells, less than the 20% cutoff for positivity. We studied 222 cases of well-characterized Burkitt lymphoma with the classic phenotype and C-MYC translocation and found 90 cases (40.5%) with multiple myeloma 1 nuclear expression, suggesting a late germinal center stage of differentiation.

Expression of p63 in anaplastic large cell lymphoma but not in classical Hodgkin's lymphoma ☆ ☆☆

Immunohistochemical determination of p63 protein is frequently used in the pathologic diagnosis of nonhematological solid tumors. In malignant hematological disease, p63 expression has been reported in 22% of follicular lymphoma, about 35% of diffuse large B-cell lymphoma, 23% of chronic lymphocytic leukemia, and in some cases of blast crisis of chronic myelogenous leukemia. Anaplastic large cell lymphoma is a rare disease that accounts for less than 5% of all cases of non-Hodgkins lymphoma. There is little information concerning p63 expression in this specific type of lymphoma. In some cases, the morphological and phenotypic features between anaplastic large cell lymphoma and classical Hodgkins lymphoma are similar, making this differential diagnosis challenging. We studied p63 expression using a tissue microarray approach in 154 cases of anaplastic large cell lymphoma, including 38% anaplastic large cell kinase positive and 62% anaplastic large cell kinase negative, and 58 Hodgkins lymphoma cases. Sixty-eight cases of anaplastic large cell lymphoma (44%) showed p63 nuclear positivity (41% of anaplastic large cell kinase positive and 47% of anaplastic large cell kinase negative). Of 130 cases of systemic-anaplastic large cell lymphoma, 42% showed p63 positivity. The neoplastic cells expressed p63 in 38% of the cases of CD45-negative/anaplastic large cell kinase-negative null cell-type anaplastic large cell lymphoma, a subgroup that offers the most difficulties in the differential diagnosis with classical Hodgkins lymphoma. In contrast, none of the cases of classical Hodgkins lymphoma demonstrated any p63 expression. These results demonstrate that p63 protein expression is frequently expressed in a subset of anaplastic large cell lymphoma cases and may be used as a potential tool in the differential diagnosis between anaplastic large cell lymphoma and classical Hodgkins lymphoma.