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Monocytes and macrophages are closely related in origin, structure and function. True histiocytic lymphoma is a neoplasm of phagocytic histiocytes and is treated as non-Hodgkin's lymphoma. Tissue involvement with myeloid leukemia, including monocytic leukemia, is called extramedullary myeloid cell tumor or granulocytic sarcoma and treated with antileukemic chemotherapy. Differentiating true histiocytic lymphoma from tissue involvement with monocytic leukemia is a rather impossible task using available morphologic, cytochemical, immunocytochemical and molecular methods. The two entities need to be unified probably more appropriately as extramedullary myeloid cell tumor of monocytic origin, and should therefore be treated as such.

Breast lymphoma is a rare disease. Both primary and secondary breast involvement have been reported. Most primary breast lymphomas are high-grade malignant neoplasms, mainly large cell and Burkitt type. Low-grade lymphomas of the breast, particularly mucosa-associated lymphoid tissue (MALT) lymphomas, have been exceedingly rare. In this report we present a patient with bilateral breast involvement by MALT lymphoma. Our patient developed localized MALT lymphoma in both breasts in a sequential fashion. She was treated with bilateral lumpectomy, followed by radiation therapy to both breasts. The patient is alive and well more than 1 year after therapy with no recurrence. We believe this is the first such case described in detail in the literature.

Among patients with bone marrow failure, differentiating acquired aplastic anemia (AA) from hypocellular refractory anemia (hypo RA) can be a difficult and challenging task. Morphological, cytochemical, immunocytochemical, and cytogenetic studies may provide tools for discriminating between both entities. In addition, differences in the pattern of proliferation and apoptosis of bone marrow cells in AA and in the myelodysplastic syndrome have been reported. Because of the correlation between p53 and apoptosis, we examined the overexpression of p53 on bone marrow biopsies in RA and AA. Our study included 14 patients with hypo RA, 14 patients with hypercellular (hyper) RA, ten patients with classic acquired AA, and 37 hematologically normal individuals. p53 was overexpressed in eight (57%) hypo RA patients and 11 (79%) hyper RA patients. All normal individuals and patients with AA showed no overexpression of p53 in their marrow. These results were statistically significant:p < 0.01 (AA vs hypo RA), p<0.001 (AA vs hyper RA), while the difference between hypo RA and hyper RA was not statistically significant. We conclude that p53 overexpression in bone marrow biopsies is a valuable tool for studying bone marrow failure and may provide additional information to help differentiate hypo RA from acquired AA.

The myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) are well-documented complications secondary to chemotherapy and radiation therapy for Hodgkin's disease (HD). The coexistence of primary MDS with HD prior to therapy is an extremely rare event which has been reported only once in the English literature. This is the second case of such combination. Both patients with MDS developed AML only 7 months after diagnosis and both died shortly after the initiation of treatment. Since these cases raise the possibility of a stem cell association with HD, we reviewed the literature for other stem cell disorders with similar association with HD prior to aggressive therapy. Four cases of stem cell disorders other than MDS were reported. These included two cases of aplastic anemia, one case of myeloid metaplasia with myelofibrosis, and one of polycythemia vera. Two of the four patients died, one of AML and the other of thrombocytopenia-related cerebral hemorrhage. The association between HD and stem cell disorders, although rare, may need to be investigated further.

* The expression of myelomonocytic-associated antigens in anaplastic large cell lymphomas (ALCLs), particularly those presenting in extranodal sites, can make their distinction from extramedullary myeloid cell tumors (EMCTs) or histiocytic tumors problematic. Yet, this distinction is clinically significant because of its therapeutic and prognostic implications. Herein, we describe a case of extranodal anaplastic lymphoma kinase-positive CD30-positive ALCL of T-cell origin in a 12-year-old boy, which was initially called an EMCT because of the expression of CD13 and HLA-DR detected by flow cytometry and the absence of other T-cell-related surface markers. However, the detection of cytoplasmic CD3 by flow cytometry prompted further studies. The tumor was composed of large cells with abundant slightly eosinophilic vacuolated cytoplasm and ovoid or reniform nuclei with a few small nucleoli. Using immunohistochemistry, the tumor was positive for CD45, CD30, CD45RO, and CD43 with a strong cytoplasmic and nuclear anaplastic lymphoma kinase stain. The tumor cells showed a T-cell clonal genotype. Electron microscopy revealed no ultrastructural features of myelomonocytic or histiocytic origin. The patient responded well to the chemotherapy and was in complete remission for 10 months at the time of submission of this manuscript. Review of the literature showed inconsistencies regarding the diagnosis, nomenclature, and, therefore, treatment and prognosis of these tumors. In addition, the CD13 expression in ALCL raises some histogenetic questions and may indicate origin from a pluripotent stem cell, misprogramming during malignant transformation, or a microenvironmental effect on lymphoid cell expression of surface antigens. Therefore, ALCL should be considered in the differential diagnosis of EMCTs or histiocytic tumors, particularly when surface marker lineage assignment is ambiguous. (Arch Pathol Lab Med. 2000;124:1804-1808)

Context.—Shwachman-Diamond syndrome (SDS) is a rare inherited disorder characterized by pancreatic insufficiency, neutropenia, and in some patients, metaphyseal dysostosis. Patients with SDS are at a high risk for development of bone marrow failure, myelodysplastic syndrome, and acute leukemia. The p53 gene plays a major role in cell-cycle regulation, particularly in the presence of a genetic alteration in DNA, a critical step for the initiation of leukemogenesis. p53 gene up-regulation and p53 protein overexpression may occur as a cellular reaction to significant DNA damage. Shwachman-Diamond syndrome and refractory anemia patients have close similarities in the prevalence of acute leukemia and in cell-cycle changes in bone marrow cells. This similarity was further investigated for p53 protein overexpression using archived tissue from patients with hematologic diseases having various leukemic propensities, including SDS and refractory anemia. Methods.—Immunohistochemical staining for p53 protein overexpression was performed on bone marrow biopsies from 9 patients with SDS. These specimens were compared with biopsies from 71 patients with acquired hematologic disorders with variable risk levels for leukemia, including acquired aplastic anemia (n = 14), refractory anemia (n = 46), and various acquired cytopenias (n = 11), as well as 37 control subjects. Results.—p53 protein overexpression was identified only in patients with SDS and in patients with refractory anemia; these groups exhibited comparable prevalences of 78% and 72%, respectively. None of the patients with acquired aplastic anemia, acquired cytopenias, or in the control group showed overexpression of p53 protein. Conclusion.—The prevalence of p53 protein overexpression in SDS is significantly different from that in acquired aplastic anemia and acquired cytopenias, but it is similar to the prevalence in refractory anemia. We speculate that p53 protein overexpression in this bone marrow failure syndrome may represent an early indicator of significant DNA genetic alteration, which is a crucial step in the process of leukemogenesis.

The expression of myelomonocytic-associated antigens in anaplastic large cell lymphomas (ALCLs), particularly those presenting in extranodal sites, can make their distinction from extramedullary myeloid cell tumors (EMCTs) or histiocytic tumors problematic. Yet, this distinction is clinically significant because of its therapeutic and prognostic implications. Herein, we describe a case of extranodal anaplastic lymphoma kinase–positive CD30-positive ALCL of T-cell origin in a 12-year-old boy, which was initially called an EMCT because of the expression of CD13 and HLA-DR detected by flow cytometry and the absence of other T-cell–related surface markers. However, the detection of cytoplasmic CD3 by flow cytometry prompted further studies. The tumor was composed of large cells with abundant slightly eosinophilic vacuolated cytoplasm and ovoid or reniform nuclei with a few small nucleoli. Using immunohistochemistry, the tumor was positive for CD45, CD30, CD45RO, and CD43 with a strong cytoplasmic and nuclear anaplastic lymphoma kinase stain. The tumor cells showed a T-cell clonal genotype. Electron microscopy revealed no ultrastructural features of myelomonocytic or histiocytic origin. The patient responded well to the chemotherapy and was in complete remission for 10 months at the time of submission of this manuscript. Review of the literature showed inconsistencies regarding the diagnosis, nomenclature, and, therefore, treatment and prognosis of these tumors. In addition, the CD13 expression in ALCL raises some histogenetic questions and may indicate origin from a pluripotent stem cell, misprogramming during malignant transformation, or a microenvironmental effect on lymphoid cell expression of surface antigens. Therefore, ALCL should be considered in the differential diagnosis of EMCTs or histiocytic tumors, particularly when surface marker lineage assignment is ambiguous.

The diagnosis of “early-stage MDS” in the pediatric population was based on the criteria for refractory cytopenia of childhood (RCC) provided by the International Consensus Classification (ICC) [2]. [...]the original description of the MonoMac syndrome by Calvo et al. [...]the authors also mention near the end of the manuscript “Cases with early-stage MDS and cytopenia without clear MDS diagnosis demonstrate phenotypic similarities, however, the inherent limitations of our study-including variations in the diagnostic criteria across submitting countries and potentially insufficient granular data-prevent confidently grouping these two diagnostic categories together”. [...]we look forward to more international collaborations in these rare disorders in order to improve understanding of the disease mechanism and improve patient outcome.