Cytokeratin-positive, CD45-negative primary centroblastic lymphoma of the adrenal gland: a potential for a diagnostic pitfall

Epstein-Barr Virus–Positive CD20- and CD45-Negative Diffuse Large B-Cell Lymphoma: A Diagnostic Challenge

Diffuse large B-cell lymphoma (DLBCL) is characterized by medium- to large-sized neoplastic cells that express a wide range of B-cell markers including CD19, CD20, CD22, and CD79a. Also, as this is a hematopoietic malignancy, there is expression of the leukocyte common antigen CD45. Lack of CD20 expression occurs in a specific rare heterogeneous subgroup of DLBCL including primary effusion lymphoma, plasmablastic lymphoma, ALK-positive large B-cell lymphoma, and large B-cell lymphoma arising in HHV8+ multicentric Castleman disease. In this article, we report a rare case of CD20- and CD45-negative Epstein-Barr virus–positive DLBCL in which the entities listed above were ruled out, thereby posing a significant diagnostic challenge. Arriving at the correct diagnosis of Epstein-Barr virus–positive DLBCL was supported by immunoreactivity for the B-cell transcription factor Oct-2 and the pan-B cell marker CD79a.

Oct2 and Bob1 are sensitive and specific markers in lineage determination of B cell lymphomas with no expression of conventional B cell markers

AIMS

Rare cases of B cell lymphomas do not express conventional B cell markers (CD20, CD79a and PAX5), and these types of lymphomas include anaplastic lymphoma kinase (ALK)-positive large B cell lymphoma, plasmablastic lymphoma, primary effusion lymphoma and the solid variant of primary effusion lymphoma, extracavitary human herpesvirus 8 (HHV8)-positive large B cell lymphoma. Establishing accurate diagnoses of these B cell lymphomas can be challenging, and often requires a large panel of immunohistochemical stains, molecular assays and cytogenetic studies. B cell-specific transcription factors, Oct2 and Bob1, have been shown to be expressed consistently in most, if not all, B cell lymphomas, and therefore we investigated the utility of Oct2 and Bob1 immunohistochemistry in lineage determination of the aforementioned B cell lymphomas.

METHODS AND RESULTS

We selected 34 cases of previously diagnosed B cell lymphomas with no or weak expression of CD20, CD79a and PAX5. Oct2 and Bob1 were positive in 74% (25 of 34) and 85% (29 of 34) of the cases, respectively. When we combined the results of these two immunostains, 94% (32 of 34) cases expressed at least one of these two markers. We also included 51 control cases of non-B cell neoplasms, and none of them expressed either Oct2 or Bob1.

CONCLUSIONS

Oct2 and Bob1 are very reliable in determining B cell lineage in the absence of expression of other pan-B cell markers, and it should provide great diagnostic benefit to include them both in a panel of immunohistochemistry to assess undifferentiated malignant neoplasms.

[New aspects of tumor pathology of the adrenal glands]

In daily routine pathology of the adrenal glands three tumor entities are important: adrenocortical tumors, adrenomedullary tumors and metastases. The differentiation of these three main tumor types can often be difficult structurally but immunostaining enables a definite diagnosis in nearly all cases. Adrenocortical tumors are positive for steroidogenic factor 1 and melan-A and always negative for chromogranin A whereas adrenomedullary tumors express chromogranin A but never keratin. A broad spectrum of antibodies is available for the identification of metastases and even the rare epithelioid angiosarcomas. For adrenocortical tumors, adenomas and carcinomas can be differentiated using three scoring systems and the Ki-67 index in adenomas should not exceed 3%. Using scoring systems and the Ki-67 index approximately 90% of cortical tumors can be differentiated into benign or malignant tumors. For pheochromocytomas two scoring systems are used for differentiating benign and malignant tumors but the results are less dependable.

Lessons we learn from hematopathology consultation in Taiwan

The appropriate management of hematology patients depends first on correct diagnoses. Expert review is important in reaching accurate diagnoses. To improve diagnostic accuracy, the Taiwan Society of Pathology and the Taiwan Division of the International Academy of Pathology has been conducting an expert consultation program for general pathologists since 2001. As per this program, we have received a total of 395 cases (406 samples) for review. We found that meaningful diagnostic discrepancies occurred frequently in hematopathology reviews. Ambiguous or nondiagnostic original reports were the major causative factor for the major discrepancy cases, which demonstrates that diagnostic uncertainty is a big problem for referring pathologists. However, the World Health Organization lymphoma classification may be poorly reproducible in countries where extensive use of an ancillary technique is not used by general pathologists. This review is intended to report the misdiagnoses most commonly seen in the hematopathology practice in Taiwan. Awareness of the easily misinterpreted entities helps to achieve the right diagnosis and improve patient care.

Hematopathologic discrepancies between referral and review diagnoses: a gap between general pathologists and hematopathologists

Abstract The World Health Organization (WHO) lymphoma classification has been widely adopted by hematopathologists. However, its practical application by general pathologists is largely unknown. Using a hematopathology consultation program in Taiwan, we reviewed 406 cases. Diagnostic discrepancies were scored based upon whether the divergence would alter disease management according to National Comprehensive Cancer Network guidelines. Major discrepancies accounted for 55% (222/406), minor discrepancies for 5% (20/406) and agreement for 40% (164/406) cases. The more common groups in major discrepancies were non-diagnostic/ambiguous referral reports (116/222, 52%), tumor type revisions (52/222, 23%) and changes from malignant to benign lesions (32/222, 14%). In a total of 259 cases of lymphoma, the concordance rates were 41% (77/187) and 33% (24/72) for B-cell and T/natural killer (NK)-cell lymphomas, respectively. It appears that the WHO approach has made lymphoma classification rather poorly reproducible at least in countries where extensive use of an ancillary technique is not employed by general pathologists.

Primary adrenal lymphoma: a systematic review

Fewer than 200 cases of primary adrenal lymphoma (PAL) have been reported. We have systematically reviewed all 187 cases of PAL reported in the English literature until June 2013, from which we drew the following conclusions: PAL is typically a highly symptomatic and aggressive, metabolically hyperactive, hypovascular, hypoechoic (and heterogeneous on ultrasound), hypodense (with slight to moderate enhancement on computed tomography), high-grade lymphoma, primarily affecting elderly males and presenting with large bilateral adrenal masses. Most cases have adrenal insufficiency, B-symptoms, and elevated lactate dehydrogenase. Hepatosplenomegaly, lymphadenopathy, concurrent or prior immune dysregulation, and bone marrow involvement are uncommon. Epstein-Barr virus positivity is observed in more than half of cases and the disease is disseminated at presentation in 18 % of cases. The two most common WHO 2008-defined PAL subtypes are diffuse large B cell lymphoma (78 %) and peripheral T cell lymphoma (7 %). The prognosis of PAL has improved with the advent of rituximab-containing chemotherapeutic regimens. According to our results, administration of chemotherapy and adrenal insufficiency are significant independent predictors of prognosis.

Flow cytometry CD45-negative B-NHL: a case report of a diffuse large B-cell lymphoma without extranodal involvement

BACKGROUND

The loss of CD45, the leukocyte-common antigen, has been described in rare cases of large B-cell lymphoma (LBCL) subtypes with extranodal involvement by immunohistochemical methods. Here we report a case of a patient with LBCL, with no extranodal lesions, which is CD45 negative by flow cytometry (FC) immunophenotyping.

METHODS

Immunophenotyping and DNA content analysis was performed by multiparametric FC on lymph node and bone marrow aspirate obtained from a 65 year old male patient.

RESULTS

Malignant B-lymphocytes were CD5-, CD10+/++, CD11c-, CD19+, CD20+/++, CD23-, CD34-, CD38-/+, CD45-, CD79b++/+++, BCL2 overexpressed, FMC7++, IgM++/+++, TdT- with Lambda light chain restriction. This pathological cellular population showed near-diploid DNA content, with a high proliferate rate.

CONCLUSIONS

To our knowledge, we describe the first case of a CD19+ B-cell non-Hodgkin lymphoma without expression of CD45 detected by FC, and the first case without extranodal involvement presentation. This case is reported not only because it is a rare one but also to raise awareness of FC users of its correct diagnosis.

Lymphome primitif unilatéral de la surrénale : à propos d’un cas

The authors report a case of unilateral primary adrenal lymphoma presenting with abdominal and dorsal pain. Primary lymphoma of the genitourinary tract, specifically adrenal localisation, is a rare disease. CT is the current best imaging modality for evaluating retroperitoneal masses and improving detection, characterization as well as assessing extension. Diagnosis is based on histology.

Primary Adrenal Lymphoma

Primary adrenal lymphoma is a rare extranodal lymphoma with characteristic clinical features including a high incidence of bilateral involvement, predominantly diffuse large B-cell histology, and a low incidence of extra-adrenal disease at diagnosis. Patients are most commonly older men presenting with fever, lumbar pain, and/or symptoms of adrenal insufficiency. Prolonged disease-free survival appears uncommon, which may reflect a publication bias and/or the presence of additional adverse prognostic factors at diagnosis in most patients. Given the rarity of this disease, no prospective chemotherapy studies have been reported. Unresolved therapeutic issues include the optimal chemotherapy regimen (with vs. without monoclonal antibody), the role of bilateral adrenalectomy and/or adjuvant radiation therapy, and the need for central nervous system prophylaxis, given recent reports raising the possibility of a high risk of parenchymal or meningeal relapse. Multicenter collaborative retrospective reviews and prospective trials are needed to address these issues.