A B-cell lymphoma-associated chromosomal translocation in a progressive transformation of germinal center

How I approach: The workup and management of patients with progressive transformation of the germinal center

Progressive transformation of the germinal center (PTGC) is a common and underrecognized cause of pediatric lymphadenopathy. PTGC may be associated with numerous systemic medical conditions that require further workup and management, including malignancy, autoimmune conditions, lymphoproliferative conditions, immunodeficiency, and infection. Given the breadth and rarity of the associated conditions, workup should be tailored to the individual patient and occur in a tiered approach. Patients with PTGC require ongoing follow-up, given their long-term risk of malignancy and recurrent PTGC.

Papillary Thyroid Cancer in a Child with Progressive Transformation of Germinal Centers

Objectives. To describe the presentation and management of a child with Progressive Transformation of Germinal Centers (PTGC), an uncommon condition characterized by significant persistent lymphadenopathy, who developed papillary thyroid carcinoma and to explore and review potential links between PTGC and neoplastic processes in the head and neck. Methods. Case presentation and literature review are used. Results. A 10-year-old female presented with a right parotid mass and cervical lymphadenopathy. Multiple biopsies revealed PTGC without malignancy. Two years later, she developed fatigue and weight gain, and a thyroid nodule was found. Fine needle aspiration was strongly suggestive of papillary thyroid carcinoma. The patient underwent total thyroidectomy and central neck dissection without surgical management of the longstanding right lateral neck lymphadenopathy. Final pathology confirmed papillary thyroid carcinoma. She was treated with radioactive iodine therapy postoperatively and remains free of disease at three years of follow-up. Conclusions. PTGC is considered a benign condition but has previously been associated with Nodular Lymphocyte Predominant Hodgkin Lymphoma (NLPHL). This is the first reported case of papillary thyroid cancer in a child with preexisting cervical PTGC and no defined risk factors for thyroid malignancy. No link has been established with thyroid carcinoma, but patients with PTGC may have a defect in immune surveillance that predisposes them to malignancy.

Classical Hodgkin lymphoma occurring in association with progressive transformation of germinal center

Progressive transformation of germinal center (PTGC) represents an asymptomatic persistent form of lymphadenopathy. We present a case of classical Hodgkin lymphoma occurring in association with PTGC. The patient was a 60-year-old woman who had noted swelling of the submandibular lymph nodes. Histopathologically, the enlarged lymph nodes appeared as multiple nodules with ill-defined and irregularly expanded germinal centers. Immunohistochemical studies indicated that the germinal center cells comprised B cells that were positive for CD10 and CD20, and negative for bcl-2. Enlarged vascular endothelial cells were present in the interfollicular areas. CD30-positive Hodgkin & Reed-Sternberg cells were seen between the interfollicular area and the mantle zone, and were surrounded by CD3-positive T-cells. In situ hybridization studies demonstrated no expression of Epstein-Barr virus-encoded small RNA in the Hodgkin & Reed-Sternberg cells. A diagnosis of classical Hodgkin lymphoma complicated by PTGC was made from the lymph node specimen.

Fluorescence Immunophenotyping and Interphase Cytogenetics (FICTION) Detects BCL6 Abnormalities, Including Gene Amplification, in Most Cases of Nodular Lymphocyte-Predominant Hodgkin Lymphoma

Context.— BCL6 translocations are a frequent finding in B-cell lymphomas of diverse subtypes, including some cases of nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). However, reliable analysis of BCL6 rearrangements using fluorescence in situ hybridization is difficult in NLPHL because of the relative paucity of neoplastic cells. Combined immunofluorescence microscopy and fluorescence in situ hybridization, or fluorescence immunophenotyping and interphase cytogenetics as a tool for the investigation of neoplasms (FICTION), permits targeted analysis of neoplastic cells.

Objective.—To better define the spectrum of BCL6 abnormalities in NLPHL using FICTION analysis.

Design.—We performed an optimized FICTION analysis of 24 lymph nodes, including 11 NLPHL, 5 follicular hyperplasia with prominent progressive transformation of germinal centers, and 8 follicular hyperplasia without progressive transformation of germinal centers.

Results.— BCL6 rearrangement was identified in 5 of 11 cases of NLPHL (46%). In addition, BCL6 gene amplification, with large clusters of BCL6 signals in the absence of chromosome 3 aneuploidy, was detected in 3 of 11 cases of NLPHL (27%). One NLPHL showed extra copies of BCL6 present in conjunction with multiple copies of chromosome 3. Altogether, we detected BCL6 abnormalities in 9 of 11 cases of NLPHL (82%). None of the progressive transformation of germinal centers or follicular hyperplasia cases showed BCL6 abnormalities by FICTION.

Conclusions.—To our knowledge, this is the first report of BCL6 gene amplification in NLPHL. Our optimized protocol for FICTION permits detection of cytogenetic abnormalities in most NLPHL cases and may represent a useful ancillary diagnostic technique.

Progressive transformation of germinal centers in children and adolescents: an intriguing cause of lymphadenopathy

BACKGROUND

The clinical implications of a diagnosis of progressive transformation of germinal centers (PTGC) in children are not well known.

METHODS

To better understand this entity, we conducted a retrospective review of all patients aged 0-18 years diagnosed with PTGC at our center between 1998 and 2010.

RESULTS

Twenty-nine patients were identified. Median age at diagnosis was 11.5 years, and median duration of follow-up was 2.8 years. Thirteen patients (45%) had a single episode of PTGC with no other associated features. Five patients (17%) had recurrent PTGC. Four patients (14%) had PTGC associated with Hodgkin lymphoma (HL): one preceding, two concurrent, and one subsequently developed HL. The most commonly associated HL was nodular lymphocyte-predominant HL. Seven patients (24%) had PTGC associated with immune disorders, including lupus, Castleman disease, and probable autoimmune lymphoproliferative syndrome. Overall, 15 patients (52%) had more than one lymph node biopsy. The cumulative incidence of a second biopsy after a diagnosis of PTGC was 42.3% ± 12.2% at 4 years. PTGC was PET-avid in all four patients tested.

CONCLUSIONS

PTGC is a nonspecific manifestation of a variety of associated conditions. There is a small risk of subsequent HL, and a larger risk of requiring multiple biopsies for recurrent PTGC. The presence of an immune disorder should be considered in patients who present with generalized lymphadenopathy, splenomegaly, immune cytopenias, and/or progression to HL. Routine surveillance imaging may not be required. Future research should determine the optimal surveillance strategy for patients with PTGC and the indications for repeat biopsies.

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.