Journal of Hematopathology最新文献

Follicular dendritic cell sarcoma is a rare mesenchymal neoplasm arising from follicular dendritic cells (FDC) of lymphoid follicles. While the majority of FDC sarcoma cases arise within lymph nodes, approximately 30% manifest in extranodal sites. Only 4 prior occurrences of intra-parotid FDC sarcomas have been documented. We are reporting a rare case of FDC of the parotid gland in a 65-year-old male with a questionable history of B-cell lymphoma. The patient underwent a right total parotidectomy and bilateral neck dissection. A diagnosis of follicular dendritic cell (FDC) sarcoma was made, with one positive intra-parotid node. The malignant cells expressed the characteristic markers for FDC sarcoma but with positivity of the melanocytic marker PRAME. This is a case of FDC sarcoma with an unusual extranodal localization in the parotid gland. Immunohistochemistry was useful in making a diagnosis although the positivity for the melanocytic marker PRAME was unusual and unreported before.

Mycosis fungoides (MF), the predominant form of cutaneous T-cell lymphoma (CTCL), poses diagnostic challenges due to its clinical and histological resemblance to benign skin disorders. Delayed diagnosis contributes to therapeutic delays, prompting exploration of advanced diagnostics tools. Next-generation sequencing (NGS) may enhance disease detection by identifying pathogenic variants common to CTCL but absent in benign inflammatory disorders. We aim to discuss novel and common pathogenic variants in CTCL to enhance the utility of NGS as a diagnostic adjunct. This pilot study employed (NGS) to identify pathogenic variants in 10 MF cases. Cases were selected based on PCR-confirmed T-cell receptor clonality, with adequate DNA for NGS. GatorSeq NGS Panel, Illumina NextSeq500, and QIAGEN Clinical Insight QCI software facilitated sequencing, analysis, and variant interpretation. NGS revealed eight novel mutations in genes including HLA-DRB1, AK2, ITPKB, HLA-B, TYRO3, and CHD2. Additionally, previously reported MF-associated mutations such as DNMT3A, STAT5B, and SOCS1 (mouse study only) were detected as well. Detected variants were involved in apoptotic, NF-kB, JAK-STAT, and TCR signaling pathways, providing insights into MF pathogenesis. Mutations in genes like APC, AK2, TYRO3, and ITPKB that regulate tumor proliferation and apoptosis were noted. MF cases were associated with HLA gene mutations. NGS may enhance MF diagnosis, as the detection of pathogenic variants, particularly those known to occur in MF, favors a neoplastic diagnosis over an inflammatory diagnosis. Continuing this work may lead to the discovery of therapeutic targets.

Merkel cell carcinoma is a very aggressive primary skin tumour with a high risk of local recurrences and lymphatic and distant metastases. The frequent association between this carcinoma and other skin tumour and lymphoid malignancies, its similar cellular morphology with leukocytes, and limited infiltration in bone marrow constituted a challenging diagnosis. We report an unusual case of an 82-year-old male who simultaneously presented Merkel cell carcinoma and acute myeloid lymphoma. The diagnosis was established through flow cytometry, immunohistochemical studies and next generation sequencing (NGS) analysis. Flow cytometry allowed for the differentiation of the two cell populations in bone marrow aspirate, which was crucial to the diagnosis of Merkel cell carcinoma and acute myeloid leukaemia (AML), after confirmed by immunohistochemistry. AML could be classified based on NGS results. Following diagnosis, the patient received palliative care and died 50 days later. immunophenotypic analysis by flow cytometry and Immunohistochemical study was crucial to establish the diagnosis of simultaneous affection of Merkel cell carcinoma and hematologic disorder.

Chronic myeloid leukemia (CML) typically presents in the chronic phase. The blast crisis phase in CML predominantly comprises the myeloid phenotype, while B-cell lymphoblastic crisis is common among the lymphoid lineages. Presentation as a T-lymphoblastic crisis is exceptionally rare. Little is known about its characteristics, treatment, and prognosis. This case study reports a patient who presented as an extramedullary blast crisis with T-lymphoblastic immunophenotype without a known prior diagnosis of CML. We performed hematoxylin and eosin staining, immunohistochemistry on the inguinal lymph node, and bone marrow biopsy. Ancillary studies including flow cytometry and cytogenetic testing were conducted as needed. BCR::ABL1 is quantitative real-time polymerase chain reaction monitored disease progression. Our patient is a 40-year-old male with no previous medical history who presented with neck stiffness and pain of one week in duration. Clinical evaluation revealed diffuse lymphadenopathy and splenomegaly. A biopsy from the inguinal lymph node revealed T-lymphoblastic lymphoma (T-LBL) (90%) and a population of myeloblasts (10%). Subsequent bone marrow biopsy showed myelocyte expansion, dwarf megakaryocytes, scattered myeloblasts (9%), and T-lymphoblasts (6%). Flow cytometry of the bone marrow aspirate revealed myeloblasts (5.4%) and T-lymphoblasts (6.3%). Genetic and molecular studies identified the BCR-ABL1 fusion. This case contributes to the medical literature by documenting a rare occurrence of extramedullary T-LBL with concurrent CML. The absence of a CML history makes the diagnosis particularly challenging and underscores the need for comprehensive and personalized treatment strategies.

Peripheral blood involvement by MF/SS has significant implications for prognosis and treatment. Flow cytometry is commonly used to assess MF/SS by analyzing the ratio of CD26- and/or CD7-CD4 + T cells and assessment of immunophenotypic abnormalities. However, distinguishing normal from abnormal cells is not always easy. In this study, we aimed to establish quantitative thresholds to better distinguish normal CD4 + T cells from neoplastic CD4 + T cells. A retrospective analysis of flow cytometry data was performed on 30 MF/SS patients with a detectable abnormal T cell population (positive), 63 patients with suspected or confirmed cutaneous involvement without a detectable abnormal T cell population (negative), and 60 healthy controls (control). CD3 and CD4 median fluorescence intensity (MFI) was normalized to internal control subsets. Among the positive cases, 50% had CD3 expression outside ± 2 SD from the mean of the negative and control group in the CD4 + CD26- subset. The corresponding specificity of this threshold was 94%. The ± 2 SD threshold showed a sensitivity of 57% and a specificity of 94% for the CD3 intensity among the CD7-negative subset. For CD4 intensity, the ± 2 SD threshold had a sensitivity of 33.3% and specificity of 95% for the CD26-negative subset and a sensitivity of 37% and specificity of 95% for the CD7-negative subset. In our study, although changes in CD3 and CD4 intensity greater than ± 2 SD were specific for MF/SS, more subtle differences in the intensity of CD3 and CD4 should not be used as the sole abnormality to make a diagnosis of circulating MF/SS.

Anaplastic large cell lymphoma (ALCL) is a rare subtype of non-Hodgkin lymphoma, with most cases harboring ALK gene rearrangement (ALK + ALCL); however, 20-50% of ALCLs do not have the rearrangement (ALK- ALCL) but exhibit distinct genetic alterations. In this report, we present an unusual case of systemic ALK- ALCL with NPM1::TYK2 fusion. Diagnosis of this case was challenging prior to the NGS findings. A comprehensive panel of immunohistochemical and in-situ hybridization studies was conducted. FISH assays were utilized to target the rearrangements of DUSP22 and TP63 genes. Moreover, next-generation sequencing (NGS) assays were performed to detect clonal rearrangements of IGH and TRG genes, somatic mutations, and potential fusions. The lymphoma cells in this case are negative for all hematolymphoid markers stained, except for CD30 expression and focal and weak CD43 expression. However, NGS studies detected clonal TRG rearrangement and NPM1::TYK2 rearrangement, which aid in the diagnosis of ALK- ALCL. NPM1::TYK2 rearrangement is a rare genetic alteration that has been reported in rare cases of primary cutaneous ALCL, mycosis fungoides, and lymphomatoid papulosis. To the best of our knowledge, this is the first reported instance of such rearrangement in systemic ALK- ALCL.

A 69-year-old with well-controlled HIV was evaluated for persistent cough, in the context of years of fatigue and influenza A infection 6 months prior. Chest CT and PET scans were notable for adenopathy concerning for a lymphoproliferative disorder. Radiologic studies also showed diffuse FDG uptake in the prostate, consistent with prostatitis. Axillary lymph node biopsy showed follicular and paracortical hyperplasia, and few germinal centers showed perifollicular non-necrotizing granulomas. Immunohistochemical staining demonstrated a predominance of IgG4 positive plasma cells. Serum protein electrophoresis (SPEP) and immunosubtraction showed a board-domed peak pattern suggestive of possible monoclonality. Serum IgG4 levels were elevated, and the patient was diagnosed with IgG4-related disease (IgG4-RD). This case highlights morphologic and SPEP patterns that can aid in supporting a diagnosis of IgG4-RD.