Hodgkin's disease biology: recent advances

Unusual ocular Hodgkinʼs-like lymphoma in a dog

Hodgkin’s disease is a malignant lymphoproliferative disease with various gross morphology. The present paper reports gross and microscopic features of Hodgkinʼs-like lymphoma in a dog. An eight years-old dog was presented to our hospital due to complete blindness associated with the presence of proliferative tissue on the globe surface. The tissue biopsy sample was soft and frigid with high bleeding tendency and was processed for histopathological evaluation. Sections of 5 μm in thickness were stained with haematoxylin-eosin and melan-A and S-100 by immunohistochemistry (IHC) for differential diagnosis with ocular melanoma. Histologically, regarding the negative Melan-A and S100 IHC findings, and particular histological features, a mixed cellularity type of Hodgkin’s disease which included a large number of lymphocytes with different size and shape together with single necrosis was diagnosed. Additionally, Reed-Sternberg cells which had a deeply lobulated nucleus were demonstrated.

Recent Advances in the Pathobiology of Hodgkin's Lymphoma: Potential Impact on Diagnostic, Predictive, and Therapeutic Strategies

From its first description by Thomas Hodgkin in 1832, Hodgkin's disease, now called Hodgkin's lymphoma, has continued to be a fascinating neoplasm even to this day. In this review, historical aspects, epidemiology, diagnosis, tumor biology, new observations related to host-microenvironment interactions, gene copy number variation, and gene expression profiling in this complex neoplasm are described, with an exploration of chemoresistance mechanisms and potential novel therapies for refractory disease.

Gray zone lymphomas in pediatric patients

Gray zone lymphomas are defined as lymphoid malignancies that cannot be reliably classified into a single distinct disease entity after all available morphologic, immunophenotypic, and molecular investigations have been performed. The 2008 World Health Organization Classification proposed 2 gray zone lesions: (1) B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma and (2) B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and classical Hodgkin lymphoma. These gray zone lesions are rare, especially in pediatric patients, and create a great challenge to both pathologists and oncologists because this differential diagnosis has direct implications for management strategies. In this manuscript, we report 2 cases of pediatric patients with gray zone lymphoma and review clinicopathologic features, treatment options, and outcomes of this uncommon tumor.

Mediastinal gray zone lymphoma: the missing link between classic Hodgkin's lymphoma and mediastinal large B-cell lymphoma

In recent years, overlap in biologic and morphologic features has been identified between classic Hodgkin lymphoma (cHL) and B-cell non-Hodgkin lymphoma. Nevertheless, the therapeutic approaches for these diseases remain different. We undertook a study of "mediastinal gray zone lymphomas" (MGZL), with features transitional between cHL nodular sclerosis (NS) and primary mediastinal large B-cell lymphoma (MLBCL) to better understand the morphologic and immunophenotypic spectrum of such cases. Twenty-one MGZL cases were identified over a 20-year period. We also studied 6 cases of composite or synchronous lymphoma with two distinct components at the same time (cHL-NS and MLBCL) and 9 sequential cases with MLBCL and cHL-NS at different times. All patients had a large mediastinal mass. Immunohistochemical studies focused on markers known to discriminate between cHL and MLBCL, including B-cell transcription factors. VJ-PCR was performed in 8 cases to look at clonality of the immunoglobulin heavy chain gene (IgH). Of the gray zone cases, 11 had morphology reminiscent of cHL-NS, but with unusual features, including a large number of mononuclear variants, diminished inflammatory background, absence of classic Hodgkin phenotype, and strong CD20 expression (11 of 11). Ten cases had morphology of MLBCL, but with admixed Hodgkin/Reed-Sternberg and lacunar cells, absent (3 of 10) or weak (7 of 10) CD20 expression, and positivity for CD15 in 7 cases. B-cell transcription factor expression in the gray zone cases more closely resembled MLBCL than cHL with expression of Pax5, Oct2, and BOB.1 in all but 1 case studied (14 of 15). MAL staining was found in 7 of 10 MGZL, and in at least one component of 6 of 7 evaluable composite or sequential MLBCL/cHL cases. Two cases of sequential lymphoma showed rearrangements of the IgH gene of identical size: one in which MLBCL was the first diagnosis and one in which MLBCL was diagnosed at relapse, indicating clonal identity for the two components of cHL and MLBCL. There is accumulating evidence that MLBCL and cHL are related entities. Further support for a relationship between MLBCL and cHL-NS is provided by composite and metachronous lymphomas in the same patient, as well as the existence of MGZL with transitional morphology and phenotype.

Evolution of classic Hodgkin lymphoma in correlation to changes in the lymphoid organ structure of vertebrates

In order to integrate evolutionary concepts into lymphoma research we mapped features of classic Hodgkin lymphoma (a disease which has been recently described to be derived from germinal center B-cells) onto a phylogenetic tree of vertebrates. Secondly, we matched the phylogenetic occurrence of classic Hodgkin lymphoma to the changes in the lymphoid organ structure during vertebrate evolution. According to our analysis, classic Hodgkin lymphoma evolved exclusively at the developmental stage of mammals. Interestingly the appearance of Hodgkin lymphoma is correlated to the evolution of germinal centers in mammals. This lends some credit to the hypothesis that genes specific to the germinal center reaction are involved in the pathogenesis of Hodgkin lymphoma. However, as evolution did not stop at the developmental stage of the mammalian stem-species, to a certain extent species with specific differences of classic Hodgkin lymphoma can be expected. One such difference is that classic Hodgkin lymphoma occurs with a significantly higher frequency in humans than in all other mammals. This could be partially due to Epstein-Barr virus (EBV) infection in approximately 40%-50% of Hodgkin disease cases, that is associated with an expression of the EBV-encoded oncogen LMP-1. In conclusion we propose that the mapping of lymphoma related characteristics onto a phylogenetic tree is a valuable new tool in lymphoma research.

Dorothy Reed and Hodgkin's disease: a reflection after a century

It has now been 100 years since Dorothy Reed, at the age of 28, wrote her paper on Hodgkin's disease. Her biography reveals the difficult lives of women entering the hitherto male-dominated field of medicine, let alone medical research. Her historic paper on Hodgkin's disease is remarkable for its brilliant observations and concise scientific reasoning. Nevertheless, she was told that as a woman she could not hope for a career as an academic pathologist. After marriage to Charles Elwood Mendenhall, Professor of Physics at the University of Wisconsin and after giving birth to four children, the second part of her career began. Motivated by the loss of her firstborn, she began a study of infant mortality, an interest that lasted throughout her career. In 1926, Mendenhall undertook a survey comparing infant and maternal mortality rates in Denmark and the United States. This influential study concluded that American mortality rates were higher because of unnecessary interference in the natural process of childbirth and recommended the education of midwives follow the Danish model. In 1937, her efforts were rewarded when Madison, WI received recognition for having the lowest infant mortality of any city in the United States. Reading Reed's paper on Hodgkin's disease, we see that her observations go far beyond a description of a specific cell. Her presentation of macroscopic and microscopic features is remarkable for the distinction between "young" and "old" growths: Reed saw Hodgkin's disease as a process, rather than the spreading of a cancer. She was the first to note that those most commonly affected are boys or young adults, especially those whose general health before the disease had been excellent. She was also the first to note anergy to tuberculin. Dorothy Reed defined Hodgkin's disease in relation to tuberculosis, described its pathologic features, and offered comments on its pathogenesis, epidemiology, and immunology that still deserve to be discussed.

Molecular morphology of Hodgkin lymphoma

No other disease entity has provided greater impetus for the development of the concept of "molecular morphology" than Hodgkin lymphoma. Efforts to understand the etiology of this enigmatic disease have stimulated the application and refinement of almost every mode of biomedical scientific exploration. Notwithstanding the vast amount of data generated, much is still unknown about this remarkable disease, serving as an ongoing inducement to the development and application of new technologies for the analysis of cells and molecules in a morphologic environment.