Post-Chemotherapy Histiocyte-Rich Pseudotumors: Radiologic and Endoscopic Mimics of Residual Lymphoma.

Development of post-chemotherapy histiocyte-rich pseudotumor (PHP) is an underrecognized event following therapy in lymphoma patients and may mimic residual tumor using current therapy monitoring protocols. We report a series of 5 patients with PHP along with a review of the literature. In our series, we describe 3 patients with persistent hypermetabolic masses by positron emission tomography-computed tomography, one with persistent terminal ileal nodules on endoscopy, and one with bone marrow involvement, a site not associated with mass-like disease. Twenty-three patients with long-term follow-up were identified from our series and review of the literature. Forty-four percent of patients received additional therapy, and only 4% of patients died of lymphoma. This study illustrates that PHPs are not identified using current lymphoma therapy monitoring algorithms and may result in overtreatment with risk for additional therapy-related complications. The need for confirmatory tissue biopsy in this setting is recommended.

Trends in Acute Lymphoblastic Leukemia Incidence in the United States by Race/Ethnicity From 2000 to 2016.

Incidence trends in acute lymphoblastic leukemia (ALL) demonstrate disparities by race and ethnicity. We used data from the Surveillance, Epidemiology, and End Results Registry to evaluate patterns in ALL incidence from 2000 to 2016, including the association between percentage of people born in a foreign country at the county level and ALL incidence. Among 23,829 persons of all ages diagnosed with ALL, 8,297 (34.8%) were Latinos, 11,714 (49.2%) were non-Latino (NL) Whites, and 1,639 (6.9%) were NL Blacks. Latinos had the largest increase in the age-adjusted incidence rate (AAIR) of ALL during this period compared with other races/ethnicities for both children and adults: The AAIR was 1.6 times higher for Latinos (AAIR = 2.43, 95% confidence interval (CI): 2.37, 2.49) than for NL Whites (AAIR = 1.56, 95% CI: 1.53, 1.59) (P < 0.01). The AAIR for all subjects increased approximately 1% per year from 2000 to 2016 (annual percent change = 0.97, 95% CI: 0.67, 1.27), with the highest increase being observed in Latinos (annual percent change = 1.18, 95% CI: 0.76, 1.60). In multivariable models evaluating the contribution of percentage of county residents who were foreign-born to ALL risk, a positive association was found for percentage foreign-born for NL Whites (P for trend < 0.01) and NL Blacks (P for trend < 0.01), but the reverse was found for Latinos (P for trend < 0.01); this is consistent with tenets of the "Hispanic paradox," in which better health outcomes exist for foreign-born Latinos.

Gelatinous bone marrow transformation and emergence of clonal Philadelphia-negative cytogenetic abnormalities with excess blasts in a patient with chronic myeloid leukemia treated with dasatinib.

Gelatinous bone marrow transformation (GBMT) is a rare pathologic entity of unclear etiology characterized by adipose cell atrophy, focal hematopoietic tissue hypoplasia, and a distinct eosinophilic substance that stains with Alcian blue at pH 2.5. It is traditionally described in the context of malnutrition and cachexia from generalized disease and is important to identify because of its potential reversibility. Several recent case reports have described GBMT in patients with chronic myeloid leukemia (CML) on the first-generation tyrosine-kinase inhibitor (TKI) imatinib. Here, we describe a case of gelatinous transformation in a patient with CML receiving the second-generation TKI dasatinib who subsequently developed clonal cytogenetic abnormalities in Philadelphia chromosome negative cells with excess peripheral blasts consistent with advanced secondary myelodysplastic syndrome. While the development of clonal cytogenetic abnormalities in Philadelphia-negative cells has been frequently described in the setting of TKI, most abnormalities are transient and generally do not effect disease progression and/or transformation like in this case. Remarkably, after TKI discontinuation, repeat bone marrow biopsies had markedly diminished amounts of gelatinous transformation - supporting reversible GBMT with TKI removal. We review the relevant pathophysiology underlying our patient's possible therapeutic-mediated complications during CML therapy in an attempt to better understand the role of TKIs in the pathogenesis of these conditions.

A 2-Year, Longitudinal, Prospective Study of the Effects of Eltrombopag on Bone Marrow in Patients with Chronic Immune Thrombocytopenia.

BACKGROUND: The long-term effects of eltrombopag on bone marrow (BM) reticulin and/or collagen deposition in previously treated adults with chronic immune thrombocytopenia (ITP) were assessed. METHODS: Three BM biopsies were collected at baseline and after 1 and 2 years of eltrombopag treatment. Specimens were centrally processed, stained for reticulin and collagen, independently reviewed by 2 hematopathologists, and rated according to the European Consensus 0-3 scale of marrow fibrosis (MF). RESULTS: Of 162 patients enrolled, 93 completed all 3 protocol-specified BM biopsies. All patients with a baseline assessment were negative for collagen. Of 159 patients assessed at baseline, 150 (94%) had normal reticulin (MF-0) and 9 (6%) had minimally increased reticulin (MF-1). After 2 years, 83/93 patients (89%) with BM biopsies had MF-0, 10 (11%) had MF-1, and none had MF-2 or MF-3. Five out of 127 patients (4%) at 1 year and 1 out of 93 (1%) at 2 years had collagen deposition. None of the patients had clinical symptoms typical of BM dysfunction or abnormalities of clinical concern based on white blood cell count or peripheral blood smear. CONCLUSION: For most patients with chronic ITP, eltrombopag is not associated with clinically relevant increases in BM reticulin or collagen formation.

Autoimmune Myelofibrosis: Clinical Features, Course, and Outcome.

BACKGROUND: Autoimmune myelofibrosis (AIMF) is an underrecognized cause of nonmalignant bone marrow fibrosis which occurs in the presence or absence of a defined systemic autoimmune disease. Patients with AIMF present with cytopenias and autoantibodies, and have a distinctive nonclonal myelofibrosis on bone marrow examination. AIMF is distinguished from primary myelofibrosis by the absence of splenomegaly, eosinophilia, or basophilia, and the absence of abnormal myeloid, erythroid, or megakaryocytic morphology. OBJECTIVES: The objective of the study was to describe the clinical presentation and outcomes of patients with AIMF. METHODS: We conducted a single-institution, retrospective chart review of patients diagnosed with AIMF to investigate clinical presentations, therapies, and outcomes. RESULTS: Twelve patients with AIMF were identified with a mean follow-up of 5.8 years. All patients had detectable autoantibodies and the majority had concomitant autoimmune disorders. Four patients experienced a complete response of cytopenias and 3 patients experienced a partial response (PR) of cytopenias with immunosuppressive therapy. One patient achieved a PR following splenectomy. No patients were diagnosed with myeloproliferative neoplasms during the follow-up period. CONCLUSIONS: AIMF contributes to cytopenias in the subset of patients with various autoimmune disorders. The majority of patients with AIMF experience an improvement in cytopenias with immunosuppressive therapy.

Characterization of a variant of t(14;18) negative nodal diffuse follicular lymphoma with CD23 expression, 1p36/TNFRSF14 abnormalities, and STAT6 mutations.

A predominantly diffuse growth pattern and CD23 co-expression are uncommon findings in nodal follicular lymphoma and can create diagnostic challenges. A single case series in 2009 (Katzenberger et al) proposed a unique morphologic variant of nodal follicular lymphoma, characterized by a predominantly diffuse architecture, lack of the t(14;18) IGH/BCL2 translocation, presence of 1p36 deletion, frequent inguinal lymph node involvement, CD23 co-expression, and low clinical stage. Other studies on CD23+ follicular lymphoma, while associating inguinal location, have not specifically described this architecture. In addition, no follow-up studies have correlated the histopathologic and cytogenetic/molecular features of these cases, and they remain a diagnostic problem. We identified 11 cases of diffuse, CD23+ follicular lymphoma with histopathologic features similar to those described by Katzenberger et al. Along with pertinent clinical information, we detail their histopathology, IGH/BCL2 translocation status, lymphoma-associated chromosomal gains/losses, and assessment of mutations in 220 lymphoma-associated genes by massively parallel sequencing. All cases showed a diffuse growth pattern around well- to ill-defined residual germinal centers, uniform CD23 expression, mixed centrocytic/centroblastic cytology, and expression of at least one germinal center marker. Ten of 11 involved inguinal lymph nodes, 5 solely. By fluorescence in situ hybridization analysis, the vast majority lacked IGH/BCL2 translocation (9/11). Deletion of 1p36 was observed in five cases and included TNFRSF14. Of the six cases lacking 1p36 deletion, TNFRSF14 mutations were identified in three, highlighting the strong association of 1p36/TNFRSF14 abnormalities with this follicular lymphoma variant. In addition, 9 of the 11 cases tested (82%) had STAT6 mutations and nuclear P-STAT6 expression was detectable in the mutated cases by immunohistochemistry. The proportion of STAT6 mutations is higher than recently reported in conventional follicular lymphoma (11%). These findings lend support for a clinicopathologic variant of t(14;18) negative nodal follicular lymphoma and suggests importance of the interleukin (IL)-4/JAK/STAT6 pathway in this variant.

Pegylated interferon for the treatment of early myelofibrosis: correlation of serial laboratory studies with response to therapy.

Pegylated interferon α-2a (Peg-IFN) has been shown to induce hematologic and molecular responses in patients with the Philadelphia-negative myeloproliferative neoplasms (MPNs), including polycythemia vera (PV) and essential thrombocythemia (ET). We describe a series of patients with long-standing MPNs among whom Peg-IFN was initiated when they developed anemia and increased bone marrow reticulin fibrosis suggestive of early transformation to post-ET (PET) or post-PV (PPV) myelofibrosis (MF). Six patients were treated with Peg-IFN for a mean duration of 33.8 months (range 2-63 months). Five patients had long-standing ET (three were calreticulin (CALR)-positive, one janus kinase 2 (JAK2)-positive, and one JAK2-negative and CALR-negative), and one had long-standing JAK2-positive PV prior to starting Peg-IFN. This is the first study to report that, concurrent with the improvement in anemia, serial laboratory studies demonstrate an increase in serum LDH and left-shifted myeloid cells in the peripheral circulation over approximately 6 months, followed by a gradual normalization of these findings. Splenomegaly also increased and then resolved among responding patients. Serial bone marrow biopsies were available, which showed little change except for improvement in the grade of reticulin fibrosis in two patients. Among patients with early transformation to PET or PPV MF, our data support the efficacy of Peg-IFN in improving hemoglobin levels and reducing splenomegaly. These peripheral blood findings should not, therefore, be considered evidence of treatment failure within the first year of Peg-IFN therapy.

Large soft-tissue masses in an adult patient with Gaucher disease.

Extra-osseous masses are rarely seen in Gaucher disease. Here we present a case of a 30-year-old patient with Gaucher disease type 3, receiving ß-glucocerebrosidase enzyme replacement therapy, who presented with slowly enlarging masses along her back. There was no osseous extension seen on imaging. Biopsy of the mass ultimately showed extensive soft tissue infiltration by Gaucher cells. No other cases of soft-tissue masses of this extent have been described in the literature, and therefore management remains unclear.

Preleukemic phase of chronic myelogenous leukemia: morphologic and immunohistochemical characterization of 7 cases.

Patients with chronic myelogenous leukemia (CML) present typically with an elevated white blood cell count (WBC) and cytogenetic or molecular genetic evidence of t(9;22)/BCR-ABL1 fusion gene. Rarely, CML patients may present with a normal or mildly elevated WBC and are asymptomatic, and we describe 7 patients in this study. The WBC in these patients ranged from 3.6 to 14.3 K/mm(3) with 50% to 73% granulocytes and 0% blasts. In all patients, t(9;22)(q34;q11.2) was detected by conventional cytogenetics, and BCR-ABL1 fusion was shown, supporting the diagnosis of preleukemic CML (pre-CML). We compared these patients with a group of 5 cases of CML in chronic phase (CML-CP) and 5 bone marrow specimens with a leukemoid reaction (n=5). Reticulin, CD34, and CD61 immunostains were performed on all bone marrow biopsy specimens. Peripheral blood absolute basophilia (≥200/mm(3)) was noted in only 4 of 7 pre-CML cases, whereas it was present in all CML-CP cases and absent in leukemoid reaction cases. The mean ±SD of microvascular density of pre-CML cases (10.0 ± 4.3 vessels/200× field) was twice that of leukemoid reaction cases (5.0 ± 1.0) (P=.02; Student t test) but similar to that of CML-CP cases (12.5 ± 3.6). Microvessels in pre-CML, highlighted by CD34, were tortuous with abnormal branching, although to a lesser extent than those found in CML-CP. Microvessels in leukemoid reaction were generally straight. The percentage of small, hypolobated megakaryocytes, highlighted by CD61 in pre-CML, was 40%, 3 times that found in leukemoid reaction cases (13%) but less than that of CML-CP cases (86%). We conclude that pre-CML should be suspected in patients with a normal to mildly elevated WBC and absolute basophilia. Bone marrow examination can usually distinguish pre-CML from a leukemoid reaction based on the percentage of small, hypolobated megakaryocytes; microvascular density; and morphologic features.

Evaluation of bone marrow reticulin in patients with chronic immune thrombocytopenia treated with eltrombopag: Data from the EXTEND study.

Thrombopoietin receptor agonists, which raise platelet counts in patients with chronic immune thrombocytopenia, may be associated with increases in bone marrow (BM) reticulin. Patients with chronic immune thrombocytopenia participating in the Eltrombopag Extended Dosing (EXTEND) study underwent BM biopsies to identify clinically relevant BM fibrosis-related increases. Specimens were centrally reviewed by 2 hematopathologists. Two hundred thirty-two biopsy specimens were collected from 117 patients treated for ≤5.5 years. Moderate to marked reticulin fibrosis was found in 2 patients. After withdrawing from the study, the biopsy of 1 patient reverted to normal. There were no other pathologic changes identified among on-treatment specimens, and no pattern of abnormal reticulin deposition associated with eltrombopag treatment was evident.

Recommendations for gross examination and sampling of surgical specimens of the spleen.

This review examines handling and processing of spleen biopsies and splenectomy specimens with the aim of providing the pathologist with guidance in optimizing examination and diagnosis of splenic disorders. It also offers recommendations as to relevant reporting factors in gross examination, which may guide diagnostic workup. The role of splenic needle biopsies is discussed. The International Spleen Consortium is a group dedicated to promoting education and research on the anatomy, physiology, and pathology of the spleen. In keeping with these goals, we have undertaken to provide guidelines for gross examination, sectioning, and sampling of spleen tissue to optimize diagnosis (Burke). The pathology of the spleen may be complicated in routine practice due to a number of factors. Among these are lack of familiarity with lesions, complex histopathology, mimicry within several types of lesions, and overall rarity. To optimize diagnosis, appropriate handling and processing of splenic tissue are crucial. The importance of complete and accurate clinical history cannot be overstated. In many cases, significant clinical history such as previous lymphoproliferative disorders, hematologic disorders, trauma, etc, can provide important information to guide the evaluation of spleen specimens. Clinical information helps plan for appropriate processing of the spleen specimen. The pathologist should encourage surgical colleagues, who typically provide the specimens, to include as much clinical information as possible.

Histopathological findings in 29 lymph node biopsies with increased IgG4 plasma cells.

IgG4-related sclerosing disease encompasses a family of disorders associated with increased numbers of IgG4 plasma cells and mass forming lesions in various tissues. Lymphadenopathy is a common finding, seen in up to 80% of cases. In the largest series of cases to date, we describe histologic, immunohistochemical, special stain and flow cytometric findings in 29 cases of enlarged lymph nodes with increased IgG4 plasma cells. Lymph node biopsies showed all resection specimens; no needle core biopsies of tissue were evaluated. Cases were considered to have increased numbers of IgG4 plasma cells using the histological criteria outlined by Cheuk and Chan (2010): IgG4 plasma cells >50 cells in a high-power field and >40% of IgG-positive plasma cells positive for IgG4. Additionally, increased intrafollicular plasma cells were a common finding. The lymph nodes showed a variety of reactive histological features including follicular hyperplasia, progressive transformation of germinal centers, interfollicular expansions, variable degrees of fibrosis, increased histiocytes and occasionally an appearance similar to that of plasma cell Castleman disease.

Role of immunoglobulin heavy and light chain gene rearrangement analysis in differentiating between benign and malignant bone marrow B-cell lymphoid aggregates.

Lymphoid aggregates are found in a minority of bone marrow biopsy and aspirate specimens, and when present, the distinction between benign and malignant aggregates can represent a diagnostic challenge. Morphologic and immunophenotypic evaluation of the aggregates can aid in that distinction but in a few cases, detection of immunoglobulin heavy chain (IGH) and kappa light chain (IGK) gene rearrangements may be needed to rule in or out a malignant disease process. We studied the role of testing for IGH/IGK rearrangements in the distinction between benign and malignant B cell-predominant lymphoid aggregates. Only a few studies have addressed this issue and most lacked an adequate number of cases for establishing statistical significance. Our study retrospectively evaluated 120 bone marrow aspirate and biopsy specimens, 79 cases originally diagnosed with benign lymphoid aggregates [4,5], and 41 demonstrating a B-cell lymphoma with malignant aggregates. Immunohistochemical stains were performed on all cases in our study and flow cytometry results were available in the vast majority of cases (98%). All patients included in our study but 9 had at least 2 years of clinical follow-up information. Of the malignant lymphoma cases, IGH/IGK rearrangements were demonstrated by polymerase chain reaction in 60% of the cases. Moreover, clonal rearrangements were identified in 15% of the cases with benign aggregates. After at least 2 years of follow-up, only one case with a positive clonality study occurring in the setting of morphologically benign-appearing bone marrow lymphoid aggregates experienced a relapse of non-Hodgkin lymphoma. Molecular analysis of the IGH and IGK genes may have utility in confirming the presence of malignancy in bone marrow aspirates and biopsy specimens. False-negative results, however, are possible due to testing limitations and sampling issues. Moreover, patients with conditions such as autoimmune disorders or infectious diseases are shown to also develop clonal B-cell lymphoid aggregates. As a result, we recommend a thorough morphological examination, informative immunohistochemical staining, accurate flow cytometric analysis, and current IGH/IGK rearrangement testing when evaluating bone marrow specimens containing B cell-predominant lymphoid aggregates, with the knowledge that molecular clonality results should be carefully interpreted in the context of morphological and immunophenotypic findings to prevent misdiagnosis.

Adult leukemic synovitis is associated with leukemia of monocytic differentiation.

BACKGROUND: Leukemic synovitis is a rare complication of adult myeloid leukemias characterized by joint pain and swelling. It is important to recognize this diagnostic challenge as it may be the initial manifestation of leukemia or of relapse. METHODS: A retrospective search of patient files from 2 teaching hospitals identified 4 adult patients who presented with large joint arthritis and concurrent or subsequent leukemic synovitis. All patients presented with inflammatory arthritis of large joints, and leukemic synovitis was identified by the presence of leukemic cells in the synovial fluid or infiltrating the synovial membrane seen at biopsy. RESULTS: A leukemia of monocytic origin-acute myelomonocytic leukemia or chronic myelomonocytic leukemia-was diagnosed in all 4 patients. In 2 cases, leukemic synovitis was the initial manifestation of leukemia. In the third case, it was the first sign of relapse, and in the remaining case, it developed shortly after diagnosis of leukemia. All patients had either osteoarthritis or rheumatoid arthritis. One patient was diagnosed simultaneously with osteoarthritis and leukemia. The remaining patients had a prior history of arthritis. CONCLUSIONS: Adult leukemic synovitis occurs in association with leukemias of monocytic differentiation. Data presented here, and review of isolated case reports, support this association. The finding of large joint arthritis as a comorbidity in these 4 cases raises questions about the role of antecedent arthritis as a predisposing factor in the pathophysiology of leukemic synovitis.

Kikuchi-Fujimoto disease involving retroperitoneal lymph nodes: An uncommon presentation.

Kikuchi-Fujimoto disease is a self-limited disease of unknown etiology that is clinically defined by fevers accompanied by tender posterior cervical lymphadenopathy. It often presents acutely or sub-acutely, and due to its non-specific features, the differential diagnosis is broad and includes infectious, autoimmune, and malignant causes. Although cases of extra-cervical disease are not uncommon, involvement of retroperitoneal lymph nodes has only rarely been reported. Here, we describe a patient with Kikuchi-Fujimoto disease who presented with fever of unknown origin, abdominal pain, and enlarged hypermetabolic retroperitoneal lymph nodes.

High lifetime incidence of adult acute lymphoblastic leukemia among Hispanics in California.

BACKGROUND: The higher incidence of acute lymphoblastic leukemia (ALL) among Hispanic children relative to that in other racial/ethnic groups is well-known. We evaluated the incidence patterns of ALL in adults. METHODS: We analyzed the incidence patterns of ALL (International Classification of Diseases for Oncology 3 codes 9835-9837) among all patients diagnosed from 1988 to 2004 in California using data from the California Cancer Registry to determine whether adult Hispanics also had higher incidence rates of ALL compared with non-Hispanic Whites (Whites). Age-adjusted incidence rates (AAIR), incidence rate ratios (IRR), and 5-year survival rates were obtained using SEER*Stat. AAIRs of other leukemia subtypes and IRRs relative to non-Hispanic Whites were also examined as references for ALL. RESULTS: AAIRs of ALL in Hispanic males and females ages 20 to 54 years were higher compared with those in White males and females (IRR, 1.99; 95% confidence interval, 1.74-2.28 and IRR, 1.91; 95% confidence interval, 1.60-2.25, respectively). A higher AAIR of ALL was also observed among older (55+ years) Hispanic females (IRR, 1.84; 95% confidence interval, 1.52-2.21), but not in males (IRR, 1.07; 95% confidence interval, 0.84-1.34). Among Hispanics, low socioeconomic status was associated with a higher AAIR compared with high/middle socioeconomic status (IRR, 1.33; 95% confidence interval, 1.04-1.70). The respective 5-year survival rates among ALL patients were 38% and 30% for Whites and Hispanics ages 20 to 54 years, and 8% and 12% for patients 55 years of age or older. Compared with other racial/ethnic groups, Hispanics did not have an increased IRR of the other major leukemia subtypes. CONCLUSION: Hispanics experience a higher incidence of ALL throughout life, but not other subtypes.

Trends in Bone Marrow Sampling and Core Biopsy Specimen Adequacy in the United States and Canada: A Multicenter Study.

OBJECTIVES: To assess bone marrow (BM) sampling in academic medical centers. METHODS: Data from 6,374 BM samples obtained in 32 centers in 2001 and 2011, including core length (CL), were analyzed. RESULTS: BM included a biopsy (BMB; 93%) specimen, aspirate (BMA; 92%) specimen, or both (83%). The median (SD) CL was 12 (8.5) mm, and evaluable marrow was 9 (7.6) mm. Tissue contraction due to processing was 15%. BMB specimens were longer in adults younger than 60 years, men, and bilateral, staging, and baseline samples. Only 4% of BMB and 2% of BMB/BMA samples were deemed inadequate for diagnosis. BM for plasma cell dyscrasias, nonphysician operators, and ancillary studies usage increased, while bilateral sampling decreased over the decade. BM-related quality assurance programs are infrequent. CONCLUSIONS: CL is shorter than recommended and varies with patient age and sex, clinical circumstances, and center experience. While pathologists render diagnoses on most cases irrespective of CL, BMB yield improvement is desirable.

Bone marrow cellularity MRI calculation and correlation with bone marrow biopsy.

PURPOSE: To calculate bone marrow cellularity from MRI and correlate with bone marrow biopsy. METHODS: Twenty-seven lymphoma patients with staging bone marrow biopsies and lumbar MRI were reviewed. Cellularity was calculated from T1 signal intensity measurements=100 - {[(marrow - CSF)/(subcutaneous fat - CSF)] X 100}. RESULTS: The histologic cellularities demonstrated significant correlation with iliac bone MRI cellularity (r=0.59, P=.001). Cellularities increased from T11 to S1. Cellularity decreased with age=67.6 - (age X 0.36). CONCLUSIONS: Marrow cellularity from MRI shows statistically significant correlation with biopsy and significant differences between vertebral levels and changes with age.