Malignant histiocytoses developing in patients with B-cell lymphomas. Report of two cases

Langerhans Cell Sarcoma Arising from Chronic Lymphocytic Lymphoma/Small Lymphocytic Leukemia: Lineage Analysis and BRAF V600E Mutation Study

Background:

the phenomenon that histiocytic/dendritic cell sarcomas may be transformed from lymphoproliferative diseases is dubbed ‘transdifferentiation’. Langerhans cell sarcoma (LCS) transdifferentiated from chronic lymphocytic leukemia/small cell lymphoma (CLL/SLL) is extremely rare. The underlying mechanisms of LCS tumorogenesis and its transdifferentiation from CLL/SLL are largely unknown.

Aims:

the authors strive to further characterize LCS, to understand the potential molecular changes in LCS and the underlying mechanisms of CLL/SLL transformation to LCS.

Materials and Methods:

a progressively enlarging right inguinal lymph node from a 68-year-old female patient with a history of CLL was biopsied and submitted for flow cytometry analysis, routine hematoxylin, and eosin (H and E) stain and immunohistochemical study. Furthermore, clonality study (fluorescent in situ hybridization (FISH) analysis with a CLL panel probes) and BRAF V600E mutation study (pyrosequencing and immunostain) were performed.

Results:

two different neoplasms, LCS and CLL/SLL, were discovered to occur simultaneously in the same lymph node. These two entities were shown to be clonally related. More importantly, for the first time, BRAF V600E mutation was detected in LCS.

Conclusions:

LCS can be transdifferentiated from CLL/SLL and BRAF V600E mutation may provide the foundation for alternative therapy of LCS.

Clonally related histiocytic/dendritic cell sarcoma and chronic lymphocytic leukemia/small lymphocytic lymphoma: a study of seven cases

Histiocytic and interdigitating dendritic cell sarcomas are rare tumors originating from bone marrow-derived myeloid stem cells. Recent studies have shown evidence of cross-lineage transdifferentiation of B cells in follicular lymphoma to histiocytic and dendritic cell sarcomas. In this study, we report the morphologic, molecular and cytogenetic analysis of seven cases of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) associated with histiocytic and dendritic cell sarcomas. All seven patients were elderly males (median age 71 years). The B-cell neoplasms preceded the development of the histiocytic and dendritic cell sarcomas in six of seven patients, and one patient had both tumors diagnosed at the same time. The tumors included four interdigitating dendritic cell sarcomas: one Langerhans cell sarcoma, one histiocytic sarcoma and one immature neoplasm with evidence of histiocytic origin. Laser-capture microdissection and PCR analysis showed identical clonal immunoglobulin gene rearrangements in the two phenotypically distinct components in all cases. There was a preferential usage of IGHV4-39 by the V-D-J gene rearrangement. By fluorescence in situ hybridization (FISH) analysis, two cases showed deletion 17p in both components, whereas four cases had normal cytogenetic findings by FISH in the CLL/SLL cells, but acquired cytogenetic abnormalities in the corresponding histiocytic and dendritic tumors. Chromosome 17p abnormalities were the most common cytogenetic abnormality detected in the sarcomas, seen in five of six cases studied. Compared with the CLL/SLL cells, the histiocytic/dendritic cells were largely negative for PAX5, but showed strong expression of PU.1 and variable and weak expression of CEBPβ. Our study provides evidence for transdifferentiation of CLL/SLL B cells to tumors of dendritic and less often histiocytic lineage, and suggests that secondary genetic events may play a role in this phenomenon.

Transformation of chronic lymphocytic leukemia/small lymphocytic lymphoma to interdigitating dendritic cell sarcoma: evidence for transdifferentiation of the lymphoma clone

Interdigitating dendritic cell sarcoma (IDCS) is a rare tumor derived from interdigitating dendritic cells. Three cases of IDCS associated with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) have been described, but no clonal relationship between the 2 neoplasms was demonstrated. We present a detailed case analysis of a CLL/SLL with metachronous IDCS and demonstrate that these 2 neoplasms are clonally related. The IDCS and CLL cells had trisomy 12 and identical monoclonal immunoglobulin heavy chain gene rearrangements. Analysis of transcription factors with a role in myeloid differentiation demonstrated PU.1 up-regulation and C/EBPalpha down-regulation in IDCS compared with CLL. High-density array comparative genomic hybridization also identified gains in part of chromosome 16q in IDCS. Our study demonstrates for the first time clonal transformation of CLL/SLL into IDCS. This phenomenon may be triggered by alterations in lineage-determining transcription programs, which result in transdifferentiation, coupled with additional oncogenic stimuli caused by chromosomal imbalances.

Transformation of B cell lymphoma to histiocytic sarcoma: somatic mutations of PAX-5 gene with loss of expression cannot explain transdifferentiation

Transdifferentiation of B cell lymphoma of germinal center cell origin to histiocytic sarcoma has recently been described but is a rare occurrence. The cause for loss of B cell differentiation in these lymphomas is unknown. We investigated whether somatic hypermutation of the PAX-5 gene, a transcription factor that is important for maintaining B cell identity and is frequently mutated in B cell lymphomas of germinal center cell origin, might be a cause for loss of PAX-5 expression and thus B cell phenotype. However, no somatic hypermutation of the PAX-5 gene was detected in the two cases we studied. The molecular basis for transdifferentiation of B cell lymphoma to histiocytic sarcoma remains therefore unresolved.

Transformation of chronic lymphocytic leukemia to lymphoma of true histiocytic type

BACKGROUND

Chronic lymphocytic leukemia (CLL) may evolve into large cell lymphoma (Richter's syndrome), prolymphocytic leukemia, acute lymphoblastic leukemia, and myeloma.

METHODS

A patient with CLL that transformed into a lymphoma of true histiocytic type is described, and the literature on the association of these two disorders is reviewed.

RESULTS

Lymphomas of true histiocytic type developing as an aggressive terminal phase of CLL previously have been reported in nine patients. Fever and rapidly increasing lymphadenopathy and splenomegaly were the most common signs and symptoms. As with de novo lymphoma of true histiocytic type, extranodal involvement of the soft tissue, gastrointestinal tract, kidneys, bone marrow, liver, and lungs was documented among the 10 patients with lymphoma of true histiocytic type transformed from CLL. The median interval between diagnosis of CLL and the evolution to lymphoma of true histiocytic type was 25.5 months. Patients with lymphomas of true histiocytic type after CLL were treated with fludarabine and various other combination chemotherapy regimens with only short-lived responses. The median time to death after transformation was only 33 days (range, 10 days to 5 months).

CONCLUSION

Lymphomas of true histiocytic type appear to represent an additional, though uncommon, form of transformation in CLL. Although their presentation is reminiscent of other intermediate to high grade lymphomas, they can be distinguished based on their morphologic and immunophenotypic features. In the patients described in this study to date, transformation of CLL to lymphomas of true histiocytic type is a poor prognostic sign, with survival generally of only days to weeks.

A case of histiocytic medullary reticulosis complicated with x-ray-irradiated oral cancer

We report the case of a patient in whom oral squamous cell carcinoma and a fatal reactive form of histiocytosis were simultaneously manifested. Our conclusions indicate that such a hematophagocytic syndrome may occur in the setting of oral squamous cell carcinoma as previously described in other malignancies.

Bone marrow findings in malignant histiocytosis and/or malignant lymphoma with concurrent hemophagocytic syndrome

We examined bone marrow specimens from 19 patients with malignant histiocytosis (MH) and/or malignant lymphoma (ML) with concurrent hemophagocytic syndrome (HS) who suffered from high fever, hepatosplenomegaly, liver dysfunction, profound cytopenia, and erythrophagocytosis. There was little lymph-node enlargement or no tumor formation. The neoplastic cells in 3 patients exhibited histiocytes/macrophages phenotype with positive reactions for fluoride-sensitive nonspecific esterase, lysozyme and CD68 (KP1). Twelve other patients showed a T-cell (CD3) phenotype, in which 5 patients expressed CD30 (BerH2) as well. B-cell characteristics with CD20 (L26), CIg. nu lambda and gamma kappa were manifest in 2 patients, but indeterminate markers were found in the 2 remaining patients. Eighteen patients showed an infiltration of large neoplastic cells mainly with noncohesive interstitial growth pattern, ranging from 1.7% to 74.2% of the nucleated cells in the bone marrow. A large number of histiocytes/macrophages and dendritic cells was diffusely observed in 15 patients. Severely decreased hematopoiesis in all three series of hematopoietic cells was found in 16 patients. Bone marrow infiltration by the neoplastic cells and numerous reactive cells with erythrophagocytosis appears to be an important factor of profound cytopenia in patients of MH and/or ML with HS. The infiltrating pattern of the neoplastic and reactive cells in the bone marrow of MH and/or ML with HS was different from that of other types of peripheral T-cell ML, B-cell ML in high grade malignancy, and Hodgkin's disease. Cell characteristics and lineage of the neoplastic cells in MH and/or ML with HS are also discussed in this study.

Influenza A and the virus associated haemophagocytic syndrome: cluster of three cases in children with acute leukaemia

At the height of the United Kingdom influenza A epidemic in December 1989, three children receiving treatment for non-T cell acute leukaemia developed pancytopenia with concomitant influenza A infection. Bone marrow histology showed prominent marrow erythrophagocytosis by morphologically mature histiocytes, consistent with the picture of virus associated haemophagocytic syndrome (VAHS). In two cases there was an initial spontaneous recovery, though recurrence of VAHS developed in one case in association with a different viral infection (cytomegalovirus) following autologous bone marrow transplantation. The third child died from cardiorespiratory failure secondary to infection with influenza A and Klebsiella pneumoniae sepsis. It is suggested that influenza A should be added to the list of infective causative agents.

Extranodal T-cell lymphoma mimicking malignant histiocytosis

We report a case of extranodal T-cell lymphoma with fever, hepatosplenomegaly, pancytopenia, and diffuse sinusoidal infiltration of the spleen, liver, and bone marrow by the tumor cells, mimicking malignant histiocytosis. This is the second case of T-gamma (T-cell suppressor) lymphoma resembling the case reported by Kadin et al. [N Engl J Med 304:648, 1981]. The lack of lymph node involvement in this case supports the theory that this type of lymphoma arises in the spleen. This paper draws attention to the extranodal T-cell lymphoma groups that mimic malignant histiocytosis and the need of immunophenotyping for a correct diagnosis. The causes for the absence of T-cell receptor gene rearrangement in T-cell tumors are discussed.

Malignant histiocytosis occurring with acute myelogenous leukemia in a patient with longstanding polycythemia vera

A 52-year-old man with polycythemia vera of 20 years duration with progression to myelofibrosis developed a mass arising from the sternum. The mass consisted of large poorly differentiated cells infiltrating skeletal muscle, with cytochemical and ultrastructural features of malignant histiocytosis. At autopsy 6 weeks later, his bone marrow and spleen were involved by acute myelogenous leukemia. This is the first reported case of malignant histiocytosis occurring in a patient with polycythemia vera, and the second report of its association with acute myelogenous leukemia. There is suggestive evidence in this case that the malignant histiocytosis may possibly have arisen from the polycythemia vera clone.