Bone Lipogranuloma Mimicking Metastatic Disease on 18F-FDG PET/CT

ABSTRACT

Primary bone lipogranuloma is an extremely rare disease associated with reactive inflammatory granulomatous reaction associated with exogenous or endogenous lipids. Herein, we report a case of bone lipogranuloma with intense 18F-FDG uptake, which mimics metastatic disease on 18F-FDG PET/CT in a patient with breast cancer.

Lymphoid aggregates in bone marrow: a diagnostic pitfall

Lymphoid aggregates in bone marrow specimens are a relatively frequent finding that may pose a diagnostic challenge for a pathologist. The distinction between reactive and neoplastic aggregates has significant clinical relevance. Although many testing modalities such as immunohistochemistry, flow cytometry and molecular studies are currently available in clinical laboratories, the appropriate utilisation of these modalities and the awareness of their potential pitfalls are important. When a neoplastic process is ruled out, the significance of benign lymphoid aggregates in bone marrow is often unclear, as they may be associated with a broad spectrum of conditions including infections, autoimmune disorders, medications, or may even be idiopathic.This review focuses on evidence-based criteria that can aid in making the distinction between benign and malignant lymphoid aggregates and discusses the advantages, disadvantages and limits of ancillary tests used for this purpose. Finally, the most common aetiologies of benign lymphoid aggregates and their associations with specific diseases are discussed.

Characteristic bone marrow findings in patients with UBA1 somatic mutations and VEXAS syndrome

VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) is a newly characterized syndrome with underlying somatic UBA1 mutations in myeloid cells linking hematologic disease with autoinflammatory rheumatologic disorders. Hematologic abnormalities, particularly peripheral blood cytopenia(s) may prompt bone marrow evaluation in patients with known or unrecognized VEXAS syndrome. This review highlights key findings and diagnostic considerations encountered during bone marrow examination in patients with this disorder. Frequently reported hematologic changes include macrocytic anemia, cytoplasmic vacuoles in myeloid and erythroid precursors, marrow hypercellularity, and varying degrees of dysplasia. Myelodysplastic syndrome and plasma cell neoplasms have been diagnosed in patients with VEXAS syndrome. Macrophage activation syndrome and/or hemophagocytic lymphohistiocytosis and monoclonal B-cell lymphocytosis have also been reported. The bone marrow is a target organ in VEXAS syndrome. Heightened awareness of the bone marrow features and hematologic complications may aid in identifying individuals with VEXAS who may benefit from increased disease surveillance or alternative therapeutic strategies.

Long-term immunosuppression and multiple transplants predispose systemic lupus erythematosus patients with cytopenias to hematologic malignancies

Cytopenias in systemic lupus erythematosus (SLE) require clinical and laboratory workup and bone marrow (BM) examination to determine the cause and for appropriate patient management. Common causes include an increase in SLE activity, immune-mediated hemolysis, iron deficiency, antiphospholipid antibody syndrome, infection, or the effect of medications. We retrospectively evaluated the clinical and laboratory findings of patients with SLE and cytopenias who had undergone BM studies to determine the indicators of malignancy.We retrospectively reviewed medical records of patients with SLE who presented with cytopenias for their disease course, medications, laboratory parameters and documented the spectrum of morphological changes in BM including CD34 expression.Twenty patients with SLE had undergone BM biopsy for evaluation of cytopenias. 14/20 (70%) of the patients had reactive BM, and the rest had hematologic malignancies involving the BM. Of these 14 patients, 8 had hypocellular marrow with loss of precursor cells (low CD34), 4 had left shift in myeloid lineage, 3 had serous atrophy, and 1had multilineage dysplasia. The 6 patients with hematologic malignancies included 2 with diffuse large B cell lymphoma, and one each of natural killer/T cell lymphoma, post-transplant lymphoproliferative disorder, Hodgkin lymphoma, and myelodysplastic syndrome evolving to acute myelogenous leukemia. The presence of autoantibodies, SLE activity, and lupus nephritis were comparable in patients with and without neoplasia. However, the duration of the use of multiple immunosuppressants, years since renal transplant (22 vs 10), multiple transplants, and the presence of other autoimmune diseases were greater in those with neoplasia. Two of the 14 patients with non-neoplastic BM and 1 with the neoplastic BM had nonhematological malignancy.Clinical and laboratory findings, the number of transplants, and the use of immunosuppressive agents can guide physicians to identify patients with a higher risk of developing hematologic malignancy. BM findings of cytopenia in SLE are often due to increased disease activity causing global cell death and dysmaturation. SLE patients presenting with cytopenias, with a history of long-term exposure to immunosuppressive drugs, should be regularly screened for hematologic and nonhematologic malignancies.

Mathematical modeling of bone marrow--peripheral blood dynamics in the disease state based on current emerging paradigms, part I

Stemming from current emerging paradigms related to the cancer stem cell hypothesis, an existing mathematical model is expanded and used to study cell interaction dynamics in the bone marrow and peripheral blood. The proposed mathematical model is described by a system of nonlinear differential equations with delay, to quantify the dynamics in abnormal hematopoiesis. The steady states of the model are analytically and numerically obtained. Some conditions for the local asymptotic stability of such states are investigated. Model analyses suggest that malignancy may be irreversible once it evolves from a nonmalignant state into a malignant one and no intervention takes place. This leads to the proposition that a great deal of emphasis be placed on cancer prevention. Nevertheless, should malignancy arise, treatment programs for its containment or curtailment may have to include a maximum and extensive level of effort to protect normal cells from eventual destruction. Further model analyses and simulations predict that in the untreated disease state, there is an evolution towards a situation in which malignant cells dominate the entire bone marrow - peripheral blood system. Arguments are then advanced regarding requirements for quantitatively understanding cancer stem cell behavior. Among the suggested requirements are, mathematical frameworks for describing the dynamics of cancer initiation and progression, the response to treatment, the evolution of resistance, and malignancy prevention dynamics within the bone marrow - peripheral blood architecture.

A close association of autoimmune-mediated processes and autoimmune disorders with chronic myelomonocytic leukemia: observation from a single institution

Chronic myelomonocytic leukemia (CMML), a clonal hematopoietic stem cell disease, may be linked to immune-mediated processes and/or autoimmune disorders (AID), although the exact pathogens are still elusive. We retrospectively analyzed 123 CMML patients in our institution. Twenty-four CMML patients (19.5%) had at least one immune-mediated disorder, most commonly idiopathic thrombocytopenic purpura, gout and psoriasis. Four of these 24 patients (15%) had more than one AID. We found that, in contrast to the general population with a prevalence rate of 3.2-5.2%, newly diagnosed CMML patients demonstrated a high prevalence and variety of immune-mediated processes and/or AID. When we compared the results with those of myelodysplastic syndromes published in the literature, the prevalence of AID in these two groups of patients is similar. Our results also showed that the presence of cytogenetic abnormalities was less in CMML patients with AID (6 of 21; 28.6%) than in those without AID (37 of 94; 39.4%), although there was no statistical significance (p = 0.334). A multicenter large cohort study of CMML with AID is recommended to illustrate the molecular relationship between the two distinct groups.