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In 2022, the World Health Organization (WHO) and International Consensus Classification (ICC) recognized TP53 as an entity-defining alteration in myeloid neoplasms, yet with differing criteria that could lead to discrepant diagnoses and affect clinical trial eligibility. We studied 67 patients with TP53 mutant myeloid neoplasms, reclassifying them using both criteria. While most cases fulfill the criteria for TP53 mutant defined entities, most discrepancies were found in cases with ≥20% blasts. Patients were stratified into three groups based on blast count (<10%, 10-19%, and ≥20%) which revealed comparable clinicopathologic features, genetic characteristics, and outcomes. Notably, patients with ≥10% blasts had shorter overall survival compared to those with <10% blasts (8.1 vs. 12.4 months; p  = 0.03). This study is among the few to examine TP53 mutant myeloid neoplasms as a single entity and suggests that the 10% blast count threshold could serve as a gateway to a more harmonized classification for these patients.

In this retrospective study, we quantified the hematogone (normal B-lineage precursor) population by flow cytometric immunophenotyping in post-transplant bone marrow biopsy specimens from adult patients who received an autologous stem cell transplant for either plasma cell myeloma (n = 57) or diffuse large B-cell lymphoma (n = 73). The majority of patients (80%) had <5% marrow hematogones post-transplant. Extreme (>10%) hematogone percentages were quite rare, seen in only four patients, and were not associated with disease progression. There was a positive association between the post-transplant day and hematogone percentage within the first year after transplant, and a negative association thereafter. Plasma cell myeloma patients with ≥5% hematogones in any post-transplant flow cytometry study had a worse overall survival as did plasma cell myeloma patients with increased hematogones (as defined by percentile) at 100 days post-transplant. These findings require further study, ideally in a prospective study design.

Plasma cell myeloma (PCM) is rare in children and young adults and therefore may be difficult to diagnose. Here we report the clinicopathologic findings of 4 patients under the age of 30 diagnosed with PCM at our institution and summarize the literature about 48 other cases of PCM in this age group. The male:female ratio was 1.2:1 and the number of cases increased with age. Children and young adults with PCM often present with a plasmacytoma and are less likely to have asymptomatic PCM than their adult counterparts. From the cases that reported ethnicity, the majority (55%) were non-white suggesting a possible ethnic predisposition to PCM in this age group. PCM should be included in the differential diagnosis of mass lesions, especially a destructive bony lesion, after more common causes have been ruled out in this age group. The optimal treatment for PCM in this patient population is unclear and conclusions into this are hampered by the paucity of cases and the lack of standardized follow-up.

Myeloid, plasma cell, and lymphoblastic neoplasms are expected findings in bone marrow but are much less commonly diagnosed as primary processes in lymph nodes. The objective of this review is to aid pathologists in recognizing common hematopoietic neoplasms in the unusual setting of initial presentation in lymph nodes. Review of historical background and evolution of testing strategies is presented to improve understanding of the need for accurate diagnosis and classification using current nomenclature. The review is based on peer-reviewed literature and the personal experience of the authors. The University of Minnesota Medical Center, Fairview provides lymph node diagnostic consultation services for its busy oncology and therapeutic hematopoietic cell transplant divisions serving patients from around the globe. Although readily recognizable when they present in bone marrow, myeloid leukemia in the form of myeloid sarcoma, plasmacytoma, and lymphoblastic lymphoma can create diagnostic and classification challenges when they present as primary lymph node pathologies. Use of all diagnostic tools may be necessary to ensure accurate and reproducible diagnoses., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objectives: Although current therapies for acute promyelocytic leukemia (APL), such as all- trans retinoic acid and arsenic trioxide, usually result in remission, some patients relapse. Early recognition of relapse is critical for prompt intervention. In this study, we systematically reviewed morphologic, immunophenotypic, and cytogenetic findings in paired diagnostic and relapsed APL cases and describe and quantify the changes in blast morphology at relapse., Methods: By electronic database search, we identified eight paired diagnostic and relapsed APL cases for which peripheral blood or bone marrow smears were available for review. For two cases, diagnostic material was available for relapse after hematopoietic cell transplantation., Results: Neoplastic hypergranular or microgranular promyelocytes with indented or bivalve nuclei predominated at diagnosis in all patients. Most patients had undifferentiated blasts at relapse and/or hypergranular blast equivalents with round to oval nuclei. Classic acute promyelocytic leukemia cells with bivalve nuclei and bundles of cytoplasmic Auer rods were easily identifiable in fewer than half of cases at diagnosis and rare to absent in all relapsed cases., Conclusions: Morphologic features of relapsed APL overlap with other types of acute myeloid leukemia, creating diagnostic challenges, especially if no history is available when relapsing patients seek treatment for care., (© American Society for Clinical Pathology, 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com)

Objectives: Isolated deletion (20q) is relatively common in myeloid neoplasms and has been rarely reported in cases of therapy-related myelodysplastic syndrome (MDS). Our aim was to characterize cases of isolated del(20q) in bone marrow biopsy specimens from patients with a history of chemotherapy with morphologic findings insufficient for a diagnosis of MDS., Methods: In this retrospective study from one institution, we identified 22 patients with isolated del(20q) and no or minimal dysplasia and evaluated clinical and pathologic characteristics., Results: Eleven of the patients had a history of chemotherapy for mostly lymphoproliferative disorders. There were no statistically significant differences in peripheral blood or bone marrow features between patients with a history of chemotherapy and those without. Three patients with a history of chemotherapy had died at last follow-up; cause of death was recurrent nonmyeloid neoplasm. None of the patients with a history of chemotherapy subsequently developed a high-grade myeloid neoplasm, whereas one of the patients who had not received prior chemotherapy developed refractory anemia with excess blasts 2., Conclusions: The presence of del(20q) as an isolated bone marrow cytogenetic abnormality in the absence of morphologic findings sufficient for a diagnosis of acute myeloid leukemia, myeloproliferative neoplasm, or MDS portends an indolent clinical course, regardless of previous exposure to chemotherapy., (© American Society for Clinical Pathology, 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introduction: Non-healing wounds can pose a medical challenge as in the case of vasculopathic venostasis resulting in a surgical ulcer. When traditional approaches to wound care fail, an amniotic patch (a dehydrated tissue allograft derived from human amnion) can function as a biologic scaffold to facilitate and enhance tissue regeneration and rehabilitation., Background: Amniotic AlphaPatches contain concentrated molecules of PGE2, WNT4, and GDF-11 which have angiogenic, trophic, and anti-inflammatory effects on tissues that may be useful in enhancing wound healing., Aim-Case Report: We present a case of a severe non-healing surgical wound in a 78-year-old male 17 days post right total knee arthroplasty. The full-thickness wound exhibited a mobile flap, measured 4 cm long × 3 cm wide, and showed undermining down to patellar tissue. We treated the wound conservatively for 6 weeks with no evidence of wound healing. Upon failure of the conservative treatment, two amniotic AlphaPatch (Amniotic Therapies, Dallas, TX, USA) were applied to the wound, and the wound healed completely in 10 weeks., Methods: In the OR, the wound was irrigated with three liters of double antibiotic solution under pulse lavage. Two dry amniotic AlphaPatch (4 cm × 4 cm) were placed over the wound with Acticoat applied on top., Results: At the two-week follow-up visit (following the incision and drainage of the wound dehiscence and application of the amniotic AlphaPatch), a central scab had formed centrally in the wound dehiscence area. At the four-week follow-up visit, the wound dehiscence area had completely scabbed over with no open areas left. At the eight-week follow-up visit, the scab had just fallen off, and the wound was healing well with immature skin representing the size of a penny. At the ten-week follow-up visit, the wound was completely healed., Discussion/conclusion: Sterile, dehydrated amniotic tissue AlphaPatches (containing trophic factors known to enhance wound healing) have proven effective in completely healing an otherwise non-healing wound in a 78-year-old male who failed six weeks of conservative wound care treatment.

Epstein-Barr virus (EBV)-positive mucocutaneous ulcer (EBV MCU) is a B-cell lymphoproliferative disorder occurring in elderly or iatrogenic immunocompromised patients. It has not been reported in solid organ transplant recipients. We observed 7 patients with EBV MCU in a cohort of 70 transplant recipients with EBV posttransplant lymphoproliferative disorder (PTLD). Transplants included: 5 renal, 1 heart, and 1 lung. Median patient age was 61; 5 were male. EBV MCU was observed in oral mucosa in 4 and gastrointestinal tract in 3. Duration of immunosuppressive therapy before EBV MCU was 0.6 to 13 years. Ulcers were undermined by inflammatory cells and polymorphic or monomorphic large cell lymphoproliferation. Reed-Sternberg-like cells were present in 5/7. Large B cells were CD20, CD30, and EBV-encoded RNA positive in all cases. Diagnosis in 3 recent patients was EBV MCU; 4 patients diagnosed before familiarity with EBV MCU were classified as monomorphic large cell (n=3) and polymorphic (n=1) PTLD. None of the patients had EBV DNA in their blood (<1000 copies/mL) at diagnosis or follow-up versus 35/44 transplant patients with systemic PTLD (P<0.001). All lesions resolved with reduced immunosuppression (7/7), change in immunosuppression (2/7), and rituximab (3/7). Five patients are living: 4 healthy, 1 awaiting second renal transplant. Two patients died 3 and 5 years after resolution of EBV MCU. No patient recurred with EBV MCU or other PTLDs. EBV MCU mimics more aggressive categories of PTLD but lacks EBV DNA in blood, which may be a useful distinguishing feature. Lesions are likely to resolve with conservative management. Awareness of EBV MCU in the posttransplant setting is necessary for appropriate diagnosis and treatment.

Intravascular large B-cell lymphoma (IVLBCL) is a mature B-cell neoplasm characterized by malignant lymphoid cells within the lumina of blood vessels and capillaries. Given its varied and nonspecific clinical manifestation, this aggressive disease is often not diagnosed until an advanced clinical stage or even at autopsy. This case highlights a patient presenting with autoimmune hemolytic anemia (AIHA) and fevers. Atypical circulating cells on a screening peripheral smear lead to flow cytometric studies highlighting an increase in large, light chain restricted CD20 positive cells. A diagnostic bone marrow biopsy was performed and trephine cores demonstrated predominantly intrasinusoidal lymphoma cells. In conjunction with additional immunophenotypic data, these studies strongly supported a diagnosis of IVLBCL. Judicious use of flow cytometry and morphology resulted in an early-stage diagnosis and likely contributed to the patient's current complete remission status following anti-CD20 therapy. Differential diagnoses for this presentation are discussed in light of serologic, immunophenotypic, histologic, and cytogenetic findings., (Copyright© by the American Society for Clinical Pathology (ASCP).)

Four patients presented with acute leukemia of ambiguous or myeloid lineage in association with Langerhans cell histiocytosis and provide evidence suggesting a common origin of the two neoplasms. One patient had a non-constitutional trisomy 21 in both the leukemic blasts and the Langerhans cells indicative of a clonal relationship. A second case expressed CD2, CD13, and CD117 on both the Langerhans cells and the blasts suggesting a possible clonal relationship. All four cases exhibited geographic intermingling of the Langerhans cell histiocytosis and acute leukemia and shared unique features including extramedullary leukemia involving lymph nodes in all cases with Langerhans cell histiocytosis only present in sites involved by acute leukemia. T-cell antigen expression was present in all cases with one meeting criteria for mixed phenotype acute leukemia, T/myeloid, not otherwise specified. These findings support the concept that coexistent Langerhans cell histiocytosis and acute leukemia is clonally related in some cases. Furthermore, these cases of acute myeloid or acute leukemia of ambiguous lineage with Langerhans cell histiocytosis share some unique features suggesting a common underlying neoplastic hematopoietic stem cell.

Objective: Video-assisted thoracoscopic lobectomy remains controversial. We compared outcomes from participants in a randomized study comparing lymph node sampling versus dissection for early-stage lung cancer who underwent either video-assisted thoracoscopic or open lobectomy., Methods: Data from 964 participants in the American College of Surgeons Oncology Group Z0030 trial were used to construct propensity scores for video-assisted thoracoscopic versus open lobectomy (based on age, gender, histology, performance status, tumor location, and T1 vs T2). Propensity scores were used to estimate the adjusted risks of short-term outcomes of surgery. Patients were classified into 5 equal-sized groups and compared using conditional logistic regression or repeated measures analysis of variance., Results: A total of 752 patients (66 video-assisted and 686 open procedures) were analyzed on the basis of propensity score stratification. Median operative time was shorter for video-assisted thoracoscopic lobectomy (video-assisted thoracoscopy 117.5 minutes vs open 171.5 minutes; P < .001). Median total number of lymph nodes retrieved (dissection group only) was similar (video-assisted thoracoscopy 15 nodes vs open 19 nodes; P = .147), as were instances of R1/R2 resection (video-assisted thoracoscopy 0% vs open 2.3%; P = .368). Patients undergoing video-assisted thoracoscopic lobectomy had less atelectasis requiring bronchoscopy (0% vs 6.3%, P = .035), fewer chest tubes draining greater than 7 days (1.5% vs 10.8%; P = .029), and shorter median length of stay (5 days vs 7 days; P < .001). Operative mortality was similar (video-assisted thoracoscopy 0% vs open 1.6%, P = 1.0)., Conclusion: Patients undergoing video-assisted lobectomy had fewer respiratory complications and shorter length of stay. These data suggest video-assisted thoracoscopic lobectomy is safe in patients with resectable lung cancer. Longer follow-up is needed to determine the oncologic equivalency of video-assisted versus open lobectomy., (Copyright 2010 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Morphologic distinction of leukemic lymphoblasts in B acute lymphoblastic leukemia (B-ALL) from their nonneoplastic counterparts in bone marrow (hematogones) can be difficult. Thus, the presence of aberrant antigen expression detectable by flow cytometry may be critical for diagnosis of B-ALL and detection of minimal residual disease. The current study examined the immunophenotype of B-lineage leukemic lymphoblasts in 200 consecutive, unique, pretreatment patient specimens. We found that all cases of B-ALL exhibited multiple immunophenotypic aberrancies by which they can be distinguished from hematogones. The most frequent aberrancies were uniform or a spectrum of expression of terminal deoxynucleotidyl transferase and CD34, underexpression of CD45, overexpression of CD10, underexpression of CD38, and underexpression of CD20. Asynchronous coexpression of CD34 and CD20 was also frequently observed. Of the 200 cases, 86.5% expressed myeloid-associated antigens, and 19.0% expressed 3 or more. Of 200 cases, 9.0% aberrantly expressed T cell-associated antigens. There were significant differences in antigen-expression patterns between adult and pediatric B-ALL. Specific aberrancies correlate with recurrent cytogenetic abnormalities in B-ALL.

The cytologic findings of an extranodal NK/T-cell lymphoma (NKTCL) presenting as a large adrenal mass with leptomeningeal involvement diagnosed by CT-guided fine-needle aspiration and cerebrospinal fluid (CSF) cytology are described. The 65-year-old Caucasian patient presented with progressive headache and multiple cranial nerve neuropathies. Magnetic resonance imaging showed leptomeningeal enhancement surrounding the conus medullaris and cauda equine, and a subsequent PET/CT demonstrated a large right adrenal gland mass. Fine-needle aspiration of the adrenal mass showed occasional large pleomorphic cells with prominent nucleoli, moderate amounts of cytoplasm, and rare large cells with sparse cytoplasmic granules admixed with numerous small lymphocytes. Initial flow cytometry from this sample showed no clonal B-cell population. Immunoperoxidase stains performed on the cell block/core specimen showed that the large atypical cells were positive for CD2, CD30, CD43 and CD56, TIA-1, granzyme, and perforin, but for none of the other T-cell markers used (CD3, CD4, CD5, CD8, CD45RO), which stained the abundant background lymphocytes. A CSF specimen showed similar neoplastic cells and flow cytometry showed an NK-cell population with aberrant immunophenotype. The cytologic findings of the neoplastic cells and the extensive panel of immunoperoxidase stains allowed the diagnosis of NKTCL, which was confirmed by the subsequent flow-cytometric immunophenotyping performed on the CSF. This is, to the best of our knowledge, the first case of NKTCL diagnosed by FNA of the adrenal gland and by CSF cytology., (2009 Wiley-Liss, Inc.)

Background: Diagnosis of Hodgkin lymphoma (HL) is sometimes complicated by the scarcity of neoplastic cells in a reactive inflammatory background. Immunophenotyping by flow cytometry (FC) has not played a significant role in HL diagnosis because of its consistent failure to identify these neoplastic cells. However, HL-infiltrating T cells have been shown to play a role in HL pathogenesis. This study characterizes the FC immunophenotype of these T lymphocytes to determine whether they can be used to assist in the diagnosis of HL., Methods: Cell suspensions from 76 lymph nodes involved by HL and 156 lymph nodes with reactive lymphadenopathy (LAD) were analyzed by flow cytometry to assess the expression of T-cell antigens., Results: The CD4:CD8 ratio and CD7 expression in both CD4(+) and CD8(+) T cells are increased in HL compared with reactive lymph nodes and there are significant differences between these features in different subtypes of HL. However, only the expression of CD7 in CD4(+) T cells distinguishes between HL and reactive LAD. This is especially true for classical HL in younger patients. Using a CD7 mean fluorescence intensity (MFI) cutoff value generated by this data, 37/47 FNA specimens were correctly diagnosed., Conclusions: There are significant differences in the immunophenotypes of HL-infiltrating T cells. Of these, the CD7 expression in CD4(+) T cells discriminates between HL and reactive LAD, suggesting that this could be a useful and practical adjunctive tool in the diagnosis of HL. It may also further our understanding of the pathophysiology of this disease., ((c) 2008 Clinical Cytometry Society.)

Background: Monoclonal gammopathy of undetermined significance (MGUS) is a common plasma cell dyscrasia, comprising the most indolent form of monoclonal gammopathy. However, approximately 25% of MGUS cases ultimately progress to plasma cell myeloma (PCM) or related diseases. It is difficult to predict which subset of patients will transform. In this study, we examined the immunophenotypic differences of plasma cells in MGUS and PCM., Methods: Bone marrow specimens from 32 MGUS patients and 32 PCM patients were analyzed by 4-color flow cytometry, using cluster analysis of ungated data, for the expression of several markers, including CD10, CD19, CD20, CD38, CD45, CD56 and surface and intracellular immunoglobulin light chains., Results: All MGUS patients had two subpopulations of plasma cells, one with a "normal" phenotype [CD19(+), CD56(-), CD38(bright +)] and one with an aberrant phenotype [either CD19(-)/CD56(+) or CD19(-)/CD56(-)]. The normal subpopulation ranged from 4.4 to 86% (mean 27%) of total plasma cells. Only 20 of 32 PCM cases showed an identifiable normal subpopulation at significantly lower frequency [range 0-32%, mean 3.3%, p << 0.001]. The plasma cells in PCM were significantly less likely to express CD19 [1/32 (3.1%) vs. 13/29 (45%), p << 0.001] and more likely to express surface immunoglobulin [21/32 (66%) vs. 3/28 (11%), p << 0.001], compared to MGUS. Those expressing CD19 did so at a significantly lower level than in MGUS, with no overlap in mean fluorescence intensities [174 +/- 25 vs. 430 +/- 34, p << 0.001]. There were no significant differences in CD56 expression [23/32 (72%) vs. 18/29 (62%), p = 0.29], CD45 expression [15/32 (47%) vs. 20/30 (67%), p = 0.10] or CD38 mean fluorescence intensities [6552 +/- 451 vs. 6365 +/- 420, p = 0.38]. Two of the six MGUS cases (33%) with >90% CD19(-) plasma cells showed progression of disease, whereas none of the cases with >10% CD19(+) plasma cells evolved to PCM., Conclusion: MGUS cases with potential for disease progression appeared to lack CD19 expression on >90% of their plasma cells, displaying an immunophenotypic profile similar to PCM plasma cells. A higher relative proportion of CD19(+) plasma cells in MGUS may be associated with a lower potential for disease progression.

Composite lymphoma (CL) is composed of 2 or more morphologically and immunophenotypically distinct lymphomas in a single anatomical site. Here we report a unique CL of the upper respiratory tract in an elderly male patient. Morphologically, the lymphoma was composed of 2 distinct and well-demarcated areas consisting of monotonous small to medium-sized lymphocytes and sheets of mature-appearing plasma cells. Immunophenotyping by both flow cytometry and immunohistochemistry revealed that the small to medium-sized lymphocytes were composed of 2 distinct subpopulations sharing a CD5(+)/CD19(+)/CD20(+)/CD22(+)/CD23(-)/FMC-7(+)/cyclin D1(+) immunophenotype but with different immunoglobulin (Ig) light and heavy chain expression, consistent with 2 immunophenotypically distinct mantle cell lymphomas (MCLs); the plasma cells were composed of CD38(bright +)/CD138(+)/IgG kappa-restricted plasma cells, consistent with a plasmacytoma. Fluorescence in situ hybridization showed the t(11;14) translocation present in the lymphocyte region but absent in the plasma cell area. Ig heavy chain gene rearrangement studies on manually dissected populations showed 2 distinct patterns for the MCL and plasmacytoma. To our knowledge, this is the first report of a 3-way CL consisting of 2 immunophenotypically distinct MCLs and a plasmacytoma.

We report our experience with flow cytometric (FC) analysis of 29 cases of anaplastic large cell lymphoma (ALCL). Morphologic analysis of processed cytocentrifuged preparations demonstrated neoplastic cells in 28 cases. In 25 of these, an aberrant lymphoid population was detected by FC analysis. The majority showed high orthogonal light scatter, similar to monocytes or granulocytes. Of the antigens CD2, CD3, CD4, CD5, and CD7, 5 cases expressed 1, 8 expressed 2, 6 expressed 3, 3 expressed 4, and 3 expressed all 5. CD4 was expressed most commonly (20/25 [80%]), followed by CD2 (18/25 [72%]), CD3 (10/25 [40%]), and CD5 and CD7 (8/25 [32%] each). CD45 was expressed in 23 of 25 cases and CD13 in 7 of 9. Of 21 cases, 13 were anaplastic lymphoma kinase (ALK)+, all of which were CD4+, vs 5 of 8 ALK - cases (P = .042). Most ALCLs can be detected and characterized by multiparameter FC analysis. However, light scatter gating on typical lymphoid regions may yield false-negative results in a substantial number of cases.

We report detailed clinical and pathologic features of four cases of anaplastic lymphoma kinase-positive diffuse large B-cell lymphoma (ALK-DLBCL), a rare entity with only 29 currently reported cases. This study is the third largest of all reported series. Biopsies from four adult patients aged 41, 49, 53, and 71 years (three lymph nodes and one nasopharyngeal mass) exhibited immunoblastic/plasmablastic morphology. By immunohistochemistry and/or flow cytometry, they expressed cytoplasmic ALK-1, CD138, VS38 (3/3), monoclonal cytoplasmic light chain, CD45, EMA, CD4, and CD57 (2/3), and were negative for CD3, CD30, CD56, and TIA-1. Two showed variable CD79a expression, and one had rare CD20(+) cells. Two of three cases exhibited rare CD43(+) reactivity. One case showed scattered cytokeratin(+) cells, which could possibly lead to a misdiagnosis of carcinoma. After CHOP and radiotherapy, two stage I patients were free of disease at 58 and 36 months, whereas a stage IV patient was dead of disease at 22 months.

Some non-Hodgkin lymphomas show marked plasmacytic differentiation. In such cases, it may be difficult to differentiate these lymphoma from plasmacytoma or myeloma, especially with limited diagnostic material. However, there may be immunophenotypic differences in the plasma cells in these disorders that distinguish them. This study characterizes the immunophenotypes of neoplastic plasma cells in 41 cases of B-lineage non-Hodgkin lymphoma and compares them with those in plasma cell myeloma. We found that plasma cells in lymphoma were significantly more likely to express CD19, CD45, and surface immunoglobulin and less likely to express CD56 than those in myeloma. We further show that CD 19 and CD56 expression can be used reliably to distinguish these entities. Myeloma-associated osseous lesions and solitary plasmacytoma of bone showed myeloma-like immunophenotypes. However, some extramedullary plasmacytomas showed lymphoma-like phenotypes, suggesting that, in reality, they may represent non-Hodgkin lymphomas with extensive plasmacytic differentiation.

Essentially all cases of precursor B-lymphoblastic leukemia/lymphoma (B-ALL) demonstrate multiple immunophenotypic aberrancies relative to normal maturing B-cell precursors (hematogones). The stability of these aberrancies has relevance to follow-up minimal residual disease analysis. We compared the immunophenotypes at diagnosis and relapse in 51 childhood and adult B-ALLs with flow cytometry (FC) using broad antibody panels. A total of 446 aberrancies were present at diagnosis (median, 9 per case; range, 2-14). All cases retained multiple aberrancies at relapse (median, 8 per case; range, 2-14). Antibody panels at relapse allowed assessment of 383 (85.9%) of the initial 446 aberrancies. Of these, 299 (78.1%) were persistent and 84 (21.9%) were lost at relapse. Overall, 73% of cases showed a loss of at least 1 aberrancy at relapse. However, new aberrancies were detected in 60% of cases. These findings suggest that FC is suitable for the detection of residual B-ALL, provided that follow-up studies are not too narrowly targeted.

In this study, we examined the usefulness of various markers on blood cell populations in the diagnosis of paroxysmal nocturnal hemoglobinuria (PNH). We also evaluated bone marrow specimens, which generally are considered less suitable than blood owing to variable expression of glycosyl phosphatidylinositol (GPI)-linked antigens during hematopoietic cell differentiation. All 15 patients in our cohort had subpopulations of CD16/CD55-deficient granulocytes and CD14/CD55-deficient monocytes ("PNH clones"). The PNH clone size of granulocytes and monocytes was greater than that of erythrocytes or lymphocytes in the majority of the cases. It is interesting that CD59 showed limited usefulness for detecting PNH+ monocytes. Normal monocytes exhibited significantly dimmer CD59 expression than normal granulocytes. PNH-deficient monocytes expressed only marginally lower CD59, making it a less robust marker for highlighting PNH+ monocytes compared with CD14 or CD55. Finally, our study demonstrated the definitive usefulness of a limited combination of markers (CD16/CD55/CD45/CD14) in detecting GPI-deficient monocytes and granulocytes in bone marrow specimens submitted for flow cytometric evaluation of cytopenias.

Background: The immunophenotypic features of angioimmunoblastic T-cell lymphoma (AILT) have not been well described., Methods: We retrospectively reviewed our institutional experience with the flow cytometric features of 16 cases of AILT., Results: Multiparameter flow cytometry was able to identify a distinct population of immunophenotypically aberrant T cells in 15 of 16 cases. In 13 lymph node specimens, the neoplastic cells ranged from 1.9 to 87% (median 23%) of cells. The ratio of reactive to neoplastic T cells ranged from 0.01 to 20 (median 1.5); reactive T cells outnumbered neoplastic in 9/13 (69%) cases. The neoplastic populations expressed CD2, CD4, CD5, and CD45RO in all cases, lacked expression of CD8 and CD56 in all cases, and showed negative or dim surface CD3 in most cases. CD10 was expressed by the neoplastic populations in 11 of 14 cases at diagnosis; in 3 of these 11 only a subpopulation of the neoplastic cells was CD10(+). CD10 tended to be absent on neoplastic cells in staging bone marrows. The neoplastic population in all but one of the 15 positive cases possessed multiple immunophenotypic abnormalities and these were generally retained during the follow-up analyses of several cases., Conclusions: These results indicate the potential utility of flow cytometry in the diagnosis and follow-up of AILT., (Copyright 2006 International Society for Analytical Cytology.)

The flow cytometric classification of CD5-positive small B-cell neoplasms is dependent largely on the differential expression of CD23 and FMC-7. Occasional CD5-positive neoplasms with prominent co-expression of these antigens are encountered, precluding definitive immunophenotypic classification. The authors studied the clinicopathologic features of 26 neoplasms with this indeterminate immunophenotype. Available morphologic material was reviewed and analysis of CYCLIN D1 derangement was performed in selected cases by a combination of immunohistochemical, molecular, and cytogenetic techniques. Individual neoplasms were classified based on correlation of morphologic features and results of CYCLIN D1 studies. The neoplasms were classified into five categories: chronic lymphocytic leukemia (14 cases), "favor chronic lymphocytic leukemia" (3 cases), mantle cell lymphoma (3 cases), lymphoplasmacytic lymphoma (1 case), and unclassifiable (5 cases). Three of the unclassifiable neoplasms had morphologic features of mantle cell lymphoma, but CYCLIN D1 derangement could not be demonstrated. Neither relative expression of CD23 and FMC-7 nor intensity of CD20 or surface immunoglobulin expression was helpful in final classification. The authors conclude that CD5-positive small B-cell neoplasms with an indeterminate immunophenotype are a heterogeneous group, requiring additional studies for final classification. The majority (65%) appear to be chronic lymphocytic leukemia, with most of the remaining cases either definitively mantle cell lymphoma or unclassifiable.

To determine whether immunophenotypic features of monocytes are useful in differentiating chronic myelomonocytic leukemia (CMML) from reactive monocytosis, multiparameter flow cytometry was used to immunophenotype 20 bone marrow samples from patients with CMML, 10 normal marrow samples, and 20 marrow samples with reactive monocytosis. Monocytes in CMML exhibited aberrant antigen expression in all 20 cases. Abnormal antigen expression also was observed in monocytes in 11 of 20 reactive marrow samples. However, aberrant expression of 2 or more antigens was significantly less frequent in reactive monocytosis than in CMML (P = .002). CD56 expression with underexpression of a myeloid marker was unique to CMML monocytes. Subpopulations of monocytes with moderate levels of CD14 were present in all 3 groups. The proportion of CD14(moderate) monocytes was highest in CMML and was 20% or more in 13 of 20 CMML cases vs 3 of 20 reactive marrow samples (P = .003) and 2 of 10 normal marrow samples (P = .007). A combination of monocytosis with 2 or more immunophenotypic aberrancies with 20% or more of marrow monocytes showing moderate CD14 expression was 67% sensitive and 100% specific for CMML.

Auer rods are a hallmark of acute myeloid leukemia but occasionally are seen in myelodysplastic syndromes (MDSs) or chronic myelomonocytic leukemia, rarely in cases with fewer than 5% blasts. The significance of this finding is unclear. We report 9 cases of this unusual phenomenon. All patients had cytopenias, isolated to a single lineage in 4. Circulating blasts were present in 8 cases (rare to 2.5%). Bone marrow blasts ranged from 0.4 to 4.9%; 1% to 32% of blasts contained Auer rods. There were variable degrees of dysplasia; 1 case closely mimicked refractory anemia with ringed sideroblasts. Cytogenetic studies in 8 cases showed clonal changes in 4. In 5 patients, acute myelogenous leukemia (AML) developed 6, 6, 5, 13, and 24 months after diagnosis; the patients subsequently died. Three patients died at 1, 1, and 8 months without progression to AML, and only 1 was alive at 10 months. MDSs with fewer than 5% blasts and Auer rods seem to be a heterogeneous group, but rapid progression to death or AML in most cases suggests that Auer rods signify an aggressive biology in MDSs with a low blast count.