Case Report: Large Granular Lymphocyte Leukemia (LGLL)—A Case Series of Challenging Presentations

Large granular lymphocyte leukemia (LGLL) represents a rare group of diseases with considerable difficulties in their correct diagnostic workup and therapy. The major challenges lie in their distinction from reactive (including autoimmune) lymphoproliferations. Moreover, monoclonal LGL proliferative diseases are in fact a heterogeneous group of disorders, as recognized by the three subtypes in the current WHO classification. It distinguishes two chronic forms (the focus of this case series), namely T-LGLL and chronic lymphoproliferative disorders of Natural Killer cells (CLPD-NK) as well as aggressive NK-cell leukemia. In the clinical routine, the variable presentations and phenotypes of T-LGLL and CLPD-NK are underappreciated. The relevant differential diagnoses range from benign reactive T-cell expansions to other mature T-cell leukemias to highly aggressive γδ-lymphomas. T-LGLL or CLPD-NK patients suffer from a wide variety of symptoms often including, but not limited to, cytopenias or classical autoimmune phenomena. They receive treatments ranging from mere supportive measures (e.g. antibiotics, growth factors, transfusions) over strategies of immunosuppression up to anti-leukemic therapies. The diagnostic pitfalls range from recognition of the subtle T-cell proliferation, repeated establishment of monoclonality, assignment to a descript immunophenotypic pattern, and interpretations of molecular aberrancies. Here, we report a series of selected cases to represent the spectrum of LGLL. The purpose is to raise awareness among the scientifically or practically interested readers of the wide variety of clinical, immunological, and phenotypic features of the various forms of LGLL, e.g. of T-cell type, including its γδ forms or those of NK-lineage. We highlight the characteristics and courses of four unique cases from two academic centers, including those from a prospective nationwide LGLL registry. Each case of this instructive catalogue serves to transport a key message from the areas of (chronic inflammatory) contexts in which LGLL can arise as well as from the fields of differential diagnostics and of various treatment options. Implications for optimization in these areas are discussed.

Lessons learned from a fatal case of tuberculous meningitis with a rapid decline in an infant

Tuberculous meningitis is a highly lethal, often underrecognized disease with characteristic clinical and imaging features which can be cured if the diagnosis and subsequent treatment are begun at early stages. Frequently, there is a delayed diagnosis of this condition due to unfamiliarity of clinicians in non-endemic areas about its presentation and diagnostic workup. This article presents a case of rapid decline and fatality due to tuberculous meningitis in an 11-month-old child from a non-TB-endemic area and describes the characteristic clinical presentation, imaging findings, and diagnostic pitfalls associated with this condition.

Nonlymphoid Hematopoietic Diseases Presenting in Bone, Soft Tissue, and Other Extranodal Sites

Context.— Although rare in everyday practice, the initial presentation of hematopoietic neoplasms other than lymphoma in the musculoskeletal system and other extranodal sites can generate challenging diagnostic problems for surgical pathologists. Objective.— To review the morphologic and immunophenotypic features of various nonlymphoid hematopoietic diseases presenting at extranodal sites, with emphasis on the inherent diagnostic pitfalls and differential diagnoses of these entities to aid surgical pathologists in their accurate recognition. Data Sources.— Cases reviewed herein represent both in-house and consult cases seen at our institution between 2010 and 2021. Conclusions.— Entities that present in this way include myeloid neoplasms and histiocytic/dendritic cell neoplasms. These tumors commonly cause nonspecific symptoms, and their histologic appearance can overlap with a variety of benign neoplasms and reactive processes. This can lead to delay in diagnosis and intervention with potentially lifesaving therapy; thus, accurate and expedient recognition is of paramount importance.

Diagnostic pitfalls in effusion fluid cytology

Effusion fluid cytology has propensity for both false positives (in up to 0.5%) and false negatives (in up to 30%) results. Methodical approach from collection step to final interpretation stage could prevent both false positives and false negatives, if the interpreter is familiar with various factors responsible for diagnostic pitfalls in effusion fluid cytology. For this discussion, these factors are categorized as mentioned below: Surface tension-related alterations in cytomorphology Improper specimen processing Many faces of reactive mesothelial cells, overlapping with those of cancer cells Proliferation-related features Degenerative changes, such as nuclear hyperchromasia and cytoplasmic vacuolation Unexpected patterns and unusual entities.

Rectosigmoid endometriosis: diagnostic pitfalls and management – A case report

Endometriosis constitutes a benign condition, occurring in 10-12% of menstruating women. Bowel involvement is estimated to occur in 5-12% with the rectosigmoid region involved in up to 90% of these cases. We present the case of a 45-year-old Caucasian female patient with rectosigmoid endometriosis.

Mayo Clinic Cases in Neuroimmunology

In the past 2 decades, diagnostics and therapeutics in neuroimmunology have rapidly evolved and increased in complexity. Diagnosis is assisted by various laboratory and advanced imaging techniques. Randomized clinical trials in multiple sclerosis and neuromyelitis optica, and smaller studies for rarer autoimmune diseases, have led to distinct immune molecule–targeted and mechanism-specific therapies. The fields of cerebrovascular medicine, neurooncology, and neuroinfectious diseases have not remained static either. All of these gains present a challenge, however, in that early and accurate neurologic diagnosis is more important than ever. In our experience, some diagnostic pitfalls lie in the interpretation of test results and images without reference to the nuances of the clinical history and examination. Although some things change (eg, technology), other things never change (eg, clinical common sense). The 83 case-based chapters focus on key components of the history, examination and test findings, and differential diagnosis, although we also reference treatment approaches extensively throughout. To bring some form to this extensive repertoire of cases, the book is divided into 3 sections covering central nervous system demyelinating disease, autoimmune neurologic disorders, and others. Illustrations include imaging and, where relevant, pathologic images and video material. Board review–style questions are also provided.