An immunophenotypic and molecular study of primary large B-cell lymphoma of bone

Follicular Lymphoma Presenting With Symptomatic Bone Involvement: A Clinicopathologic and Molecular Analysis of 16 Cases

Primary bone lymphoma (PBL) is rare and mostly represented by diffuse large B-cell lymphomas (DLBCL). Follicular lymphoma (FL), albeit commonly disseminating to the bone marrow, rarely presents primarily as bone lesions. Here, we studied 16 patients (12 men:4 women, median age 60 years) who presented with bone pain and/or skeletal radiologic abnormalities revealing bone FL. Lesions were multifocal in 11 patients (spine ± appendicular skeleton), and unifocal in 5 patients (femoral, tibial, or vertebral). An infiltrate of centrocytes and centroblasts (CD20+ CD5- CD10+ BCL2+ BCL6+) with abundant reactive T cells and an increased reticulin fibrosis massively replaced the marrow spaces between preserved bone trabeculae. The pattern was diffuse ± nodular, often with paratrabecular reinforcement and/or peripheral paratrabecular extension. Ki-67 was usually <15%. Two cases had necrosis. BCL2 rearrangement was demonstrated in 14 of 14 evaluable cases (with concomitant BCL6 rearrangement in one). High-throughput sequencing revealed BCL2, KMT2D, and TNFRSF14 to be the most frequently mutated genes. After staging, 5 qualified for PBL (3 limited stage) and 11 had stage IV systemic FL. All patients received rituximab ± polychemotherapy as firstline treatment, and 7 received local therapy (6 radiotherapy and 2 surgery). Three patients experienced transformation to DLBCL. At the last follow-up (15/16, median 48 months), 11 patients achieved complete remission, including all cases with PBL and most patients with limited extraosseous disease (3-year progression-free survival 71%). One patient died of unrelated cause (3-year overall survival 91%). FL may manifest as a localized or polyostotic bone disease. A minority represent PBL, whereas most reveal systemic disease.

MR features of primary bone lymphoma in children

BACKGROUND

Primary lymphoma of bone is an uncommon non-Hodgkin lymphoma. Magnetic resonance imaging (MRI) features of primary lymphoma of bone in children are not well described.

OBJECTIVE

To identify typical MRI characteristics of pediatric primary lymphoma of bone at diagnosis and following treatment.

MATERIALS AND METHODS

Two pediatric radiologists retrospectively reviewed all imaging studies of 10 patients with biopsy-proven primary lymphoma of bone at presentation and after treatment. Anatomic location, number of sites, location within bone (epiphyseal, metaphyseal, diaphyseal), T1-weighted imaging margins, soft tissue mass, T2-weighted imaging appearance and enhancement pattern (homogeneous, heterogeneous, infarct-like), soft tissue edema, cortical disruption, and regional lymph nodes as seen on MRI as well as radiographic and positron emission tomography (PET) findings were recorded. Pathologic results, treatment plans, and outcomes at follow-up as detailed in the medical record were tabulated.

RESULTS

Of 10 patients, age at diagnosis 8-17 years, median 15 years, 4 (40%) had multifocal disease. MRI revealed 20 total lesions in the 10 patients with femoral lesions most common, being present in 7 (70%) of patients. Eight (80%) patients had at least one lesion around the knee. Eight (80%) patients had 1 or more lesions involving an epiphysis and 5 (50%) had at least 1 lesion confined to the epiphysis. Seven (70%) showed infarct-like appearance on T2-weighted imaging; 7 (88%) of the 8 patients with post-contrast imaging had infarct-like enhancement. Six (60%) had sharp T1 margins, 3 (30%) had cortical disruption, 8 (80%) had at least mild soft tissue edema, and 1 (10%) had soft tissue mass. Three (30%) had at least 1 PET-positive regional lymph node. At follow-up (range 1-108 months, median 4.3 months), all had residual osseous abnormality on MRI with 6 (60%) maintaining an infarct-like or combination of infarct-like and T2 hyperintense appearance.

CONCLUSION

Our results in this series of pediatric primary lymphoma of bone identified several frequent MR imaging features. Multifocality, epiphyseal involvement (especially about the knee), infarct-like enhancement pattern, sharp T1 margins, and surrounding soft tissue edema should raise suspicion for primary lymphoma of bone. Following treatment, residual osseous abnormality is expected on MRI.

Primary Bone Lymphoma of the Shaft of the Tibia, Mimicking Subacute Osteomyelitis

We present the case of a 32-year-old healthy male who presented with a three-month history of insidious onset pain and swelling over the right tibia. Initial radiographs and imaging pointed to a diagnosis of subacute osteomyelitis, as there was no cortical destruction, periosteal reaction, or soft tissue involvement. The patient underwent surgery for osteomyelitis. However, the histopathology and immunohistochemistry (IHC) findings pointed to a possible B-cell lymphoma diagnosis. The patient was referred to a tertiary-level oncology centre, where a repeat biopsy and positron emission tomography (PET) scan confirmed a diagnosis of primary bone lymphoma (PBL). Treatment was initiated immediately in the form of a combination of chemotherapy and radiotherapy, and the progress was followed up with further scans at four-month intervals. The patient achieved remission nine months after the initiation of treatment.

Primary Bone Lymphoma: A Review of the Literature with Emphasis on Histopathology and Histogenesis

Primary bone lymphoma (PBL) is a rare neoplasm of malignant lymphoid cells presenting with one or more bone lesions without nodal or other extranodal involvement. It accounts for approximately 1% of all lymphomas and 7% of malignant primary bone tumors. Diffuse large B-cell lymphoma (DLBCL), not otherwise specified (NOS) represents the predominant histological type and constitutes over 80% of all cases. PBL may occur at all ages with a typical diagnosis age of 45–60 years and a slight male predominance. Local bone pain, soft tissue edema, palpable mass and pathological fracture are the most common clinical features. Diagnosis of the disease, which is frequently delayed due to its non-specific clinical presentation, is based on the combination of clinical examination and imaging studies and confirmed by combined histopathological and immunohistochemical examination. PBL can develop in any part of the skeleton, although it occurs most commonly in the femur, humerus, tibia, spine and pelvis. The imaging appearance of PBL is highly variable and unspecific. In terms of the cell-of-origin, most cases of primary bone DLBCL (PB-DLBCL), NOS belong to the germinal center B-cell-like subtype and specifically originate from germinal center centrocytes. PB-DLBCL, NOS has been considered a distinct clinical entity based on its particular prognosis, histogenesis, gene expression and mutational profile and miRNA signature. PBL carries a favorable prognosis, especially when treated with combined chemoradiotherapy.

The multilobated morphology is still a better prognosis factor of diffuse large B-cell lymphoma in the R-CHOP era

Diffuse large B-cell lymphoma (DLBCL) is the most common type of B-cell lymphoma. Although the multilobated subtype of DLBCL has been observed since the 1970s, little is known about the clinical significance of this unique variant in the era of rituximab, cyclophosphamide, hydroxydaunorubicin, oncovin, prednisone/prednisolone (R-CHOP) therapy. In this study, the retrospective clinicopathological analysis of 312 patients diagnosed with DLBCL showed that the multilobated DLBCL group comprised 11% of the cases and was predominantly male (p = 0.027), achieved complete remission in the first therapy (p = 0.023), and exhibited germinal center B-cell phenotypes in the Hans algorithm (p = 0.025). The multilobated DLBCL groups had a better prognosis in overall survival (OS) and progression-free survival (PFS) than the non-multilobated DLBCL group (OS, p = 0.006; PFS, p = 0.010). In the multivariate Cox regression analyses for OS, independent prognosis factors were high soluble IL-2 receptor (p = 0.025), high risk of International Prognostic Index, and multilobated morphology (p = 0.031). The most characteristic copy number gains found in more than 50% of the cases were located at 1q, 3p, 10q, 12q, and 14q. Overall, the multilobated morphology in DLBCL exhibits a good outcome in the R-CHOP era.

Primary bone anaplastic lymphoma kinase positive anaplastic large-cell lymphoma: A case report and review of the literature

BACKGROUND

Primary bone lymphoma (PBL) is an uncommon extranodal disease that represents approximately 1%-3% of lymphomas. Anaplastic lymphoma kinase (ALK) positive anaplastic large-cell lymphoma (ALCL) is an extremely rare type of PBL. The aim of this report is describe the symptoms, diagnosis, and treatment of primary bone ALK-positive ALCL.

CASE SUMMARY

A 66-year-old man presented to our hospital with neck and shoulder pain and intermittent fever that lasted for 1 mo. After extensive evaluation, positron emission tomography-computed tomography (CT) examination showed multiple osteolytic bone lesions without other sites lesions. CT-guided biopsy of the T10 vertebral body was performed, and the pathology results showed that neoplastic cells were positive for ALK-1, CD30, and CD3. A diagnosis of primary bone ALK positive ALCL was ultimately made. The patient was in partial response after four cycle soft cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy, and we planned to repeat the biopsy and radiological examination after completion of the fifth cycle of therapy.

CONCLUSION

Primary bone ALK positive ALCL is a rare disease and physicians should keep in mind that ALCL can present with isolated osseous involvement without nodal involvement, and lymphoma should be considered in the differential diagnosis of primary bone lesions.

[Adult non-Hodgkin bone lymphomas]

Two forms of bone lymphomas can be distinguished: the primary bone lymphoma (PBL) and the secondary bone lymphoma (SBL). PBL is a rare disease with a good prognosis. Clinical manifestations and imaging findings are usually non-specific. Patient can present with pain, swelling of affected bone or pathologic fracture. Positron emission tomography-CT scan is a sensitive imaging modality and very useful for staging, restaging, surveillance of recurrence, and monitoring of treatment response of lymphoma. The diagnosis of PBL is often difficult and made after biopsy examination. Most patients have diffuse large B-cell lymphoma. Patients have been treated with radiotherapy, chemotherapy or combination of both. Localized disease, low IPI (International Prognostic Index) and complete remission after initial treatment were associated with a better outcome. Management of late sequelae deserves particular attention. SBL is more common than PBL; this is a disseminated lymphoma with concomitant involvement of the skeleton. We review the clinical, imaging and pathologic features of bone lymphomas; and discuss therapeutic modalities as well as prognosis of these lymphomas in the era of immunochemotherapy.

Primary Bone Lymphoma in Axial Skeleton in a Middle-Aged Female Presented as Recurrent Anemia

Primary bone lymphoma (PBL) is a peculiar extranodal presentation of non-Hodgkin's lymphoma. Primary bone diffuse large B-cell lymphoma (DLBCL) is the most common pathological type, comprising about 80% of PBL. The diagnosis of PBL depends on the combined clinical examination and imaging studies and is confirmed with immunohistochemical examination. Due to the rarity of this disease, more relative studies and case reports are needed to provide insight into this obscure lymphoproliferative malignancy. Here, we report one rare case of primary bone DLBCL involving the axial skeleton in a 37-year-old female.

Primary Bone Lymphoma: A Case Series and Review of Literature

Primary bone lymphoma (PBL) is a subtype of lymphoma that exclusively affects skeletal tissue. Despite the relatively common involvement of skeletal structures as a manifestation of non-Hodgkin's lymphoma (NHL), primary and exclusive involvement of the skeletal system is rare. The prevalence of PBL is estimated to be 3–7% amongst primary bone tumors and less than 2% amongst all lymphomas in adults. However, the definition of primary bone lymphoma has been inconsistent over time. Within our institution, we identified four cases of primary bone lymphoma based on diagnostic criteria formed from the general consensus of multiple organizations, including the World Health Organization (WHO) and International Extranodal Lymphoma Study Group (IELSG). Here, we discuss the distinct characteristics amongst these cases in addition to performing a systematic review of current literature regarding this lymphoproliferative entity.

Primary lymphoma of the tibia in children: Two case reports

RATIONALE

Primary lymphoma of the bones (PLB) is a rare extranodal non-Hodgkin lymphoma (NHL) that is particularly rare in children. The clinical presentation and radiological features of PLB are often nonspecific, making clinical diagnosis challenging and misdiagnosis frequent. Here, we report 2 children with PLB focusing on clinical presentation, differential diagnosis, and treatment outcomes.

PATIENTS CONCERNS

A 9-year-old boy presented with left knee swelling and pain for 4 months after a fall. He was previously misdiagnosed with traumatic soft tissue injury. The second patient was an 11-year-old boy with a 6-month history of intermittent left knee pain. He was previously misdiagnosed with bone tuberculosis and chronic osteomyelitis.

DIAGNOSES

A 9-year-old boy showed an abnormal signal of the left tibia metaphysis, diaphysis, and epiphysis, and tibia with periosteal reactions and surrounding soft tissue swelling. Tumor biopsy and immunohistochemistry confirmed a diagnosis of B-cell lymphoblastic lymphoma.An 11-year-old boy showed a permeative lesion in the metaphysis and diaphysis of the left proximal tibia. Tumor biopsy and immunohistochemistry confirmed the diagnosis of diffuse large B-cell lymphoma.

INTERVENTIONS

Both patients were treated with 6 courses of NHL-Berlin-Frankfurt-Münster-95.

OUTCOMES

Both patients are in complete clinical remission with a follow-up of 27 and 18months after treatment, respectively.

LESSONS

PLB is a rare malignancy that is difficult to diagnose, particularly in children. Clinicians should increase the awareness of the disease and consider a differential diagnosis of bone lesions. Chemotherapy combined with radiotherapy is a favorable treatment for children with PLB. Early diagnosis and active treatment can improve patient prognosis.

A rare case report of primary bone lymphoma and a brief review of the literature

Primary bone lymphoma is a rare and peculiar extranodal presentation of non-Hodgkin’s lymphoma, which threatens human health. It can be defined as a lymphoma that occurs in the bone, consisting of a single bone lesion with or without regional lymphadenopathies, and its underlying causes are largely unknown. In this case report, we describe a male who presented with left-sided distal forearm pain, swelling of 2 months duration, and progressive limited wrist motion for about 1 month. The patient had no significant medical history except diabetes. Magnetic Resonance Imaging demonstrated a sheet-like bone destruction area in the left-sided radius, localized discontinuous bone cortex, and adjacent soft tissue masses. Finally, a bone biopsy examined by histopathological and immunochemical methods confirmed a diagnosis of primary bone diffuse large B-cell lymphoma. Due to the rarity of this disease, the level of evidence supporting some diagnostic and therapeutic decisions remains low, and therefore, the details of the rare case may facilitate treatment of similar diseases and provide insight about this obscure lymphoproliferative malignancy. Also, related recent literature reports of primary bone lymphoma are reviewed.

Primary and secondary bone lymphomas

Recent studies have contributed to the enhancement of clinical and molecular knowledge on bone lymphomas, a group of rare malignancies with particular characteristics. Nevertheless, several questions remain unanswered and the level of evidence supporting some diagnostic and therapeutic decisions remains low. Currently, three different forms of bone lymphomas can be distinguished: the primary bone lymphoma, consisting of a single bone lesion with or without regional lymphadenopathies; the polyostotic lymphoma, consisting of multifocal disease exclusively involving the skeleton; and the disseminated lymphoma with secondary infiltration of the skeleton. The first two forms exhibit a good prognosis, requiring treatments similar to those commonly used for nodal lymphomas of the same category, but several issues regarding the role of surgery and local control of the disease, the sequence of treatment, radiation volumes and doses, management of pathological fractures and prevention of late sequelae deserve particular attention. Due to its rarity, prospective trials exclusively focused on bone lymphomas appear unrealistic, thus, critical revision of our own experience and analyses of large cumulative series as well as molecular studies on archival cases remain valid alternatives to improve our knowledge on this obscure lymphoproliferative malignancy. The present review is based on the analysis of the largest available database of bone lymphomas established under the sponsorship of the International Extranodal Lymphoma Study Group (IELSG) as well as on the critical revision of related literature. We provide recommendations for diagnosis, staging, treatment, and response assessment of these patients in everyday practice as well as for the management of special conditions like pathological fractures, indolent forms and central nervous system prophylaxis.

Primary diffuse large B-cell lymphoma associated with chronic osteomyelitis of the knee

Diffuse large B-cell lymphoma (DLBCL) associated with chronic inflammation is a recently adopted category of DLBCL, which describes an aggressive B-cell lymphoma raised in the setting of non-immune chronic inflammation. Primary presentation of this subtype of DLBCL in bone is extremely rare. Here, we present the case of a 27 year old woman with DLBCL of the right distal femur, identified after a three-year history of chronic osteomyelitis. In this report, we describe the clinical and histopathologic features of this unusual presentation of DLBCL and discuss aspects relevant to diagnosis and treatment of this entity.

An unusual presentation of primary lymphoma of the ilium

Primary bone lymphoma involving the pelvic bone is a rare entity. It does not have distinct clinical features or radiological features that are diagnostic. Biopsy is the gold standard investigation. We present a case of primary pelvic lymphoma with initial histopathological features of chronic osteomyelitis. Upon further clinical follow-up, repeat biopsy of the lesion revealed features of B-cell Non-Hodgkin's lymphoma, thus emphasizing the need for a high index of suspicion and close clinical follow-up. This case is presented for the diagnostic dilemma and the unique feature of lymphomatous lesion mimicking chronic osteomyelitis in its early stages.

Primary bone lymphoma: A case report and review of the literature

Primary lymphoma of the bone (PLB) primarily arising from the medullary cavity is an extremely rare entity, with only retrospective studies and sporadic cases reported in the literature. The current study presents one case of PLB treated with chemotherapy and radiotherapy, and a review of the literature to elucidate the optimal treatment of PLB. A 73-year-old female presented with pain in the left hip that had persisted for two months. Plain X-ray and magnetic resonance imaging of the left hip showed lytic areas involving the left innominatum. Technetium-99m radionuclide imaging showed increased tracer uptake in the ilium, acetabulum and ischium. An ¹⁸F-fluorodeoxyglucose-positron emission tomography-computed tomography (FDG-PET-CT) scan showed high FDG uptake. A fine-needle aspiration biopsy of the lesion was performed, and histopathological and immunohistochemical examination confirmed a diagnosis of B-cell lymphoma. The patient received radiation therapy followed by six cycles of CHOP regimen (1,000 mg cyclophosphamide, 80 mg epirubicine and 2 mg vincristine on day one, and 100 mg prednisone on days one to five, every three weeks) and achieved a complete response, as confirmed by FDG-PET-CT. At present, the patient is in a good condition. This case is noteworthy, as it is a well-documented case in which the patient received successful treatment. This case demonstrates that PLB has an improved prognosis compared with primary lymphoma of other sites; however, combined therapy may further improve the patient outcome.

Primary bone lymphoma of the left radius: a case report and related literature review

Primary bone lymphoma (PBL) is a rare but distinct clinicopathological disease. Because it is not common, the optimal treatment strategy has not been established. Here, we present a patient with PBL of the left radius and review the related literature. We focus on the standard treatment for PBL. Many aspects such as rehabilitation, local control and overall survival need to be considered. Studies on this disease should be carried out to clarify the optimal treatment in the future.

Pathology of extra-nodal non Hodgkin lymphomas

In the management of extra-nodal lymphomas it is important to determine whether the tumour has disseminated and whether lymph nodes are involved. Some extra-nodal lymphomas may be the result of random spread of nodal lymphoma. Specific homing, however, determines the site of many extra-nodal lymphomas, as exemplified by cutaneous T-cell lymphomas, which seem to be derived from skin-homing T-cells and mucosa-associated lymphoid tissue lymphomas that show features of the mucosal immune system. Enteropathy-associated T-cell lymphoma is derived from mucosal T-cells in patients with coeliac disease. Immunological sanctuary accounts for the localisation of primary brain, eye and testicular lymphoma. Mantle cell lymphoma frequently causes tumours in the gastrointestinal tract. Random biopsies have shown that a high proportion of patients with this lymphoma have extensive occult involvement of the gastrointestinal tract at the time of first diagnosis. Follicular lymphoma occurs at both nodal and extra-nodal sites, but uncommonly at both sites at the same time. Extra-nodal follicular lymphomas frequently lack t(14;18)(q32;q21) and do not express bcl-2, which are characteristics of the nodal disease. At extra-nodal sites, follicular lymphoma is more likely to be curable than nodal follicular lymphoma. The behaviour of extra-nodal lymphomas cannot be assumed to follow that of their nodal counterparts.

Extranodal manifestations of lymphoma on [¹⁸F]FDG-PET/CT: a pictorial essay

Lymphoma is the seventh most common type of malignancy in both sexes. It is a neoplastic proliferation of lymphoid cells at various stages of differentiation and affects lymph nodes with infiltration into the bone marrow, spleen and thymus. However, extra nodal involvement is frequently seen in many cases. With the development of dedicated positron emission tomography (PET) scanners with fused computed tomographic (CT) systems in the same gantry, [18F]fluorodeoxyglucose (FDG)-PET/CT has become a major tool in the evaluation of lymphomas and it is inimitable in certain situations such as assessment of response to therapy. Extranodal lymphoma can present with diverse manifestations and sometimes mimics other organ-related pathologies. Knowledge of the protean manifestations of extranodal lymphoma is required to accurately detect the disease and differentiate it from the various physiologic and benign causes of FDG uptake in various organs. We present a case series of extranodal involvement of histologically proven cases of lymphomas detected on FDG-PET/CT at our institute to demonstrate the challenges in interpretation of extranodal lymphoma.

Calcium- and integrin-binding protein 1 regulates endomitosis and its interaction with Polo-like kinase 3 is enhanced in endomitotic Dami cells

Endomitosis is a form of mitosis in which both karyokinesis and cytokinesis are interrupted and is a hallmark of megakaryocyte differentiation. Very little is known about how such a dramatic alteration of the cell cycle in a physiological setting is achieved. Thrombopoietin-induced signaling is essential for induction of endomitosis. Here we show that calcium- and integrin-binding protein 1 (CIB1), a known regulator of platelet integrin α_IIbβ₃ outside-in signaling, regulates endomitosis. We observed that CIB1 expression is increased in primary mouse megakaryocytes compared to mononuclear bone marrow cells as determined by Western blot analysis. Following PMA treatment of Dami cells, a megakaryoblastic cell line, we found that CIB1 protein expression increased concomitant with cell ploidy. Overexpression of CIB1 in Dami cells resulted in multilobated nuclei and led to increased time for a cell to complete cytokinesis as well as increased incidence of furrow regression as observed by time-lapse microscopy. Additionally, we found that surface expression of integrin α_IIbβ_3, an important megakaryocyte marker, was enhanced in CIB1 overexpressing cells as determined by flow cytometry. Furthermore, PMA treatment of CIB1 overexpressing cells led to increased ploidy compared to PMA treated control cells. Interestingly, expression of Polo-like kinase 3 (Plk3), an established CIB1-interacting protein and a key regulator of the mitotic process, decreased upon PMA treatment of Dami cells. Furthermore, PMA treatment augmented the interaction between CIB1 and Plk3, which depended on the duration of treatment. These data suggest that CIB1 is involved in regulating endomitosis, perhaps through its interaction with Plk3.

Primary bone lymphoma

Primary bone lymphomas are rare, even though secondary involvement of the bone marrow is a common event in systemic lymphomas. Most primary bone lymphomas are primary bone diffuse large B-cell lymphomas (PBDLBCLs) with a rare occurrence of follicular, marginal zone, anaplastic large cell, Hodgkin, and T-cell lymphomas. The PBDLBCL affects the middle-aged to elderly population, with a slight predominance in men. The patients present with bone pain, palpable mass, fractures, or neurologic symptoms. The metaphysis of bones is a common location of PBDLBCL. Morphologically, the lymphoma consists of a polymorphous mixture of small to large cells with multilobated nuclei, fine chromatin, and inconspicuous to prominent nucleoli. Differential diagnoses for PBDLBCL include chronic osteomyelitis, primary bone sarcoma, leukemic infiltrate, Ewing sarcoma, metastatic sarcomas, and carcinoma. Most PBDLBCLs are treated with combined radiotherapy and chemotherapy with good prognosis.

Diffuse Large B-Cell Lymphoma—More Than a Diffuse Collection of Large B Cells: An Entity in Search of a Meaningful Classification

Context.—Diffuse large B-cell lymphoma is a heterogenous group of lymphomas. In this review, we present a brief description of the large number of entities recognized in the recently published (2008) World Health Organization classification of tumors of hematopoietic and lymphoid tissues.

Objective.—We highlight the unique clinicopathologic and molecular genetic features of these new and previously recognized entities, to illustrate the rational for the development of this classification. To help simplify the understanding of this now large and complex group of diseases, we have attempted to create broader subgroups of related entities. We discuss large B-cell lymphoma that are not otherwise specified, those that are based on anatomic site, those that have unique histology or phenotype or genotype, those that are associated with Epstein-Barr virus or Kaposi sarcoma–associated herpesvirus and herpesvirus 8, and those that are unclassifiable.

Data Sources.—World Health Organization classification of tumors of hematopoietic and lymphoid tissues (2008), published literature from PubMed (National Library of Medicine), and primary material from the authors' institution were reviewed.

Conclusions.—Recognition of the different subtypes of diffuse large B-cell lymphoma as described in the World Health Organization classification scheme will lead to improved understanding of the unique clinicopathologic and genetic features associated with these subtypes of lymphoma.

Extranodal lymphoma

Lymphomas arising in extranodal sites are intriguing. The types of lymphomas encountered vary widely from one extranodal site to another. For many types of extranodal lymphomas, there are distinctive clinicopathologic features, sometimes including association with an underlying immunodeficiency syndrome, autoimmune disease, infection, or other immunologic disorder, or a predilection to affect patients of certain ethnic origins. Presented below is a review of lymphomas that are encountered most often in extranodal sites.

SHP-1 expression in primary central nervous system B-cell lymphomas in immunocompetent patients reflects maturation stage of normal B cell counterparts

SHP-1 is an important negative regulator involved in signaling through receptors for cytokine/growth factors, and differential patterns of SHP-1 expression in several types of B-cell lymphomas closely resemble the patterns seen in their normal B cell counterparts. In an effort to elucidate the origin of primary central nervous system lymphomas (PCNSL), the present study assessed 32 cases of PCNSL. Tumors were subclassified according to WHO classification and were evaluated by immunohistochemistry for expression of antigens associated with germinal center (GC) (CD10, Bcl-6) and non-GC stages (SHP-1, CD138). Twenty-nine cases showed diffuse large-cell centroblastic morphology, whereas three cases showed diffuse large-cell immunoblastic morphology. The immunophenotypes of PCNSL were as follows: SHP-1+/Bcl-6-/CD10-/CD138- (12 of 32 cases); SHP-1+/Bcl-6+/CD10-/CD138- (15 of 32 cases); SHP-1+/Bcl-6+/CD10+/CD138- (two of 32 cases); SHP-1+/Bcl-6-/CD10+/CD138- (one of 32 cases); and SHP-1-/Bcl-6-/CD10-/CD138- (two of 32 cases). These results indicate that PCNSL might be distinct lymphomas that originate from a late germinal center to an early postgerminal center.

Detection of bcl-2 and bax expression and bcl-2/JH fusion gene in intrahepatic cholangiocarcinoma

AIM: To investigate the relationship between bcl-2 gene and its related protein bax and intrahepatic cholangiocellular carcinoma (CCC).

METHODS: Semi-nested in situ PCR (SNISPCR) and imm- unohistochemistry were performed to detect bcl-2/JH fusion gene and bcl-2, bax protein expression in 29 cases of CCC.

RESULTS: No bcl-2/JH fusion gene was found in all cases of CCC, 72.4% of 29 cases expressed bcl-2 protein. Bcl-2 protein expression was related to histopathological grades (P < 0.05). There was no corresponding relationship between bcl-2/JH fusion gene formation and bcl-2 protein expression in CCC (P < 0.05). Bax was expressed in 10.3% of 29 cases. The ratio of bcl-2 to bax in normal liver tissues (3.5 to 1) was different from that in tumor tissues (7.0 to 1).

CONCLUSION: It is suggested that bcl-2/JH fusion gene formation is not a frequent event and may not play an important role in the pathogenesis of CCC. However, aberrant ratio of bcl-2 to bax protein expression may be involved in the course of tumorigenesis of CCC. Abnormal bcl-2 protein expression may not be solely resulted from bcl-2/JH fusion gene.

Primary bone lymphoma: radiographic-MR imaging correlation

Primary bone lymphoma is an uncommon malignancy that accounts for less than 5% of all primary bone tumors. The radiographic appearances of primary bone lymphoma are variable, and, because the lesion can appear near normal on plain radiographs, a second modality such as bone scintigraphy or magnetic resonance (MR) imaging should be used. Despite this variability, the presence of a solitary, permeative, metadiaphyseal lesion with a layered periosteal reaction on plain radiographs and a soft-tissue mass on MR images, especially in a patient older than 30 years, is highly suggestive of lymphoma. The case for a diagnosis of primary bone lymphoma is further strengthened if the soft-tissue mass and marrow changes are associated with surprisingly little cortical destruction. Primary bone lymphoma has a better prognosis than many other malignant bone tumors; therefore, early identification allows for appropriate treatment. MR imaging not only permits early identification but also depicts the extent of soft-tissue involvement and can be used to assess the outcome of treatment.

Diffuse large B-cell lymphoma of bone: an analysis of differentiation-associated antigens with clinical correlation

Twenty-nine patients with diffuse large B-cell lymphomas presenting with bone involvement, including 18 localized primary bone lymphomas (group 1), 2 multifocal primary bone lymphomas (group 2), and 9 patients with extraskeletal disease at diagnosis (group 3), were studied. The tumors were subclassified according to the criteria of the WHO classification and evaluated by immunohistochemistry for expression of antigens associated with germinal center (GC) and non-GC stages of B-cell differentiation (bcl-6, CD10, MUM-1, VS38c, CD138, bcl-2, and CD44). The presence of a BCL-2/IgH gene rearrangement was investigated by polymerase chain reaction. All cases were characterized by similar clinicopathologic and morphologic features and had similarly good overall outcome. The patients (23 males, 6 females, median age 44 years) had tumors in long bones (14), axial skeleton (8), limb girdles (3), and multiple sites (4). Most tumors (24) were centroblastic, with multilobated cells in 12 cases. Almost half of the tumors (14 of 29, 48%) were bcl-6+CD10+ (GC-like), 9 of 29 cases (31%) were bcl-6+CD10- (indeterminate phenotype), and 6 of 29 cases (21%) were CD10-bcl-6- (post-GC like). The indeterminate phenotype was seen only in primary bone lymphoma. MUM-1 was frequently expressed in GC-like and non-GC-like categories. We found no evidence of plasmacytic differentiation by CD138, and VS38c immunoreactivity was distinctly rare (2 of 29 cases). CD44 was detected in 6 tumors, all CD10-. Bcl-2 was expressed by 70% of the tumors, but only 1 of 23 cases tested had a Bcl-2/JH rearrangement by polymerase chain reaction. A survival analysis showed that GC-like tumors had a longer overall survival duration compared with non-GC-like tumors (P = 0.0046). In conclusion, a GC-like immunophenotype characterizes roughly half of large B-cell lymphomas of bone and is associated with an improved survival.

Primary and secondary cutaneous diffuse large B-cell lymphomas: a multiparameter analysis of 25 cases including fluorescence in situ hybridization for t(14;18) translocation

Although primary cutaneous diffuse large B-cell lymphomas (DLBCLs) except for those of the leg are grouped together with primary cutaneous follicle center cell lymphoma in the European Organization for Research and Treatment of Cancer classification of primary cutaneous lymphomas, they typically lack the usual phenotypic profile of follicular lymphoma. Whether they are truly of follicular center cell origin, have a molecular pathogenesis similar to nodal follicular lymphoma, or have any biologic features that distinguish them from secondary DLBCL involving skin remains uncertain. To address these issues, a retrospective multiparameter study of 25 patients including clinical, histologic, immunophenotypic, and cytogenetic analyses was performed. A classic CD10+, bcl-6+ follicular center cell profile was found in 10 (40%) cutaneous DLBCL (2 of 11 primary, 5 of 8 secondary, 3 of 6 unclassified) with bcl-2 expression seen only in the nonprimary cases. Of the remaining cases, 14 cases (56%) were CD10-, bcl-6+, bcl-2+/- (9 primary) and one case (4%) was CD10-, bcl-6-, bcl-2+ (0 primary). Fluorescence in situ hybridization analysis showed a t(14;18) in 0 of 9 primary and 3 of 5 secondary cases. Primary cases were frequently found in the head/neck region, whereas secondary cases were more common on the trunk and extremities. Patients with primary disease were all alive, usually having received only local therapy, at a median follow-up of 19 months. Most secondary cases were treated with chemotherapy with only one untreated patient dead of disease at a median follow-up of 5 months. Primary cutaneous DLBCLs therefore appear to be distinctive as they have fewer features of follicular lymphoma than do secondary cases. Nevertheless, some appear to be of follicular center cell origin, even though they probably have a different molecular pathogenesis than most nodal follicular lymphomas.

Lymphomas of the bone: a pathological and clinical study of 54 cases

We examined 28 cases of primary bone lymphomas (PBL; stage IE) and 26 cases of systemic lymphomas involving the bone (SBL; stage IIE to IV). Two histologic types were prevalent: Diffuse large B-cell lymphomas (DLBCL; 26 PBL and 21 SBL) and CD30+ anaplastic large cell lymphomas (ALCL; 1 PBL and 4 SBL). A mature B phenotype (CD45+, CD20+, CD79a+, CDw75+/-, CD10-/+) was established in the DLBCL group. Bcl-2 immunoreactivity was demonstrated in 13/37 cases (35%), and bcl-6 immunostaining was observed in 22/32 cases (69%). ALCL showed null/T phenotype (CD3-/+; CD43+/-; CD30+), with ALK-1 expression in 3/3 cases. With use of a FR3A primer, a monoclonal pattern was demonstrated by PCR analysis in 22/41 lymphomas (54%). Bcl-2 translocation was identified in 2/41 cases (5%). This study details the clinical and pathological characteristics of bone lymphomas. Our immunohistochemical and molecular data suggest that most of them are "de novo" DLBCL and support their follicle center origin.