Journal of Hematopathology最新文献

Anaplastic large cell lymphoma with primary presentation in, and disease limited to, the central nervous system (primary CNS ALCL) is a rare and aggressive lymphoma found in a sensitive anatomic site. We report the clinical and pathologic characteristics of 17 primary CNS ALCL cases that are newly reported from six academic medical centers. We are investigating the characteristics of these cases, alongside their commonalities and differences from systemic ALCL arising at conventional anatomic sites. Clinical, pathologic, and outcome data were extracted by medical record review. The median patient age was 32 years with a male-to-female ratio of 2.4:1. Cases presented with either localized or multifocal central nervous system (CNS) disease without coinciding systemic disease. Histologically, the common pattern prevailed, and loss of pan-T-cell markers was frequent. There was a similar proportion of anaplastic lymphoma kinase (ALK) positivity in primary CNS ALCL (12/17, 71%) compared to that reported in systemic ALCL (70-80%). Our data indicate a 5-year overall survival (OS) rate of 65% and a 5-year progression-free survival (PFS) rate of 48%. Five patient deaths occurred in this study of which all were in the ALK-negative group, and all were patients over 40 years old. ALK-positive patients were significantly younger than ALK-negative patients, and survival analyses showed that both ALK-positive and younger age (≤ 40 years) were favorable prognostic factors. This is the largest series of primary CNS ALCL reported to date, which demonstrates a high proportion of ALK-positive cases and favorable outcomes for both younger and ALK-positive patients despite the involvement of a sensitive anatomic site.

Targeted immunotherapy is a promising approach in treating high-risk and refractory/relapsed lymphoid malignancies. Although this strategy has shown a significant success in treating non-Hodgkin B-cell lymphomas and plasma cell myeloma, relapse with loss of targeted antigen can occur. Rarely, complete loss of multiple lineage specific markers can happen. We are describing 2 cases of B-cell neoplasms along with contributing immunohistochemistry, cytogenetic, and molecular results. Post-targeted CAR-T therapy, both cases, one aggressive B-cell lymphoma and the other plasma cell myeloma, lost B-cell, and plasma cell antigens, respectively. Complete loss of lineage specific markers post-targeted therapy is a rare event that makes the diagnosis of the relapsed neoplasm challenging. In this article, we also reviewed the literature and highlighted possible mechanisms of antigen loss following targeted therapy.

Mantle cell lymphoma (MCL) is a rare and aggressive type of lymphoma that can affect the kidneys. The disease can lead to kidney impairment, and glomerulonephritis (GN) is a rare but serious complication of MCL. We report a case of MCL with kidney interstitial infiltration and membranoproliferative glomerulonephritis with focal and segmental glomerulosclerosis. A 75-year-old man presented recurrent acute kidney failure and worsening of nephrotic syndrome. Kidney biopsy revealed membranoproliferative glomerulonephritis presented immunoglobulin and complement deposition, focal and segmental glomerulosclerosis of not otherwise specified type, and infiltration by mantle cell lymphoma. Bone marrow biopsy and PET/CT scan confirmed the diagnosis of mantle cell lymphoma. The patient was treated with R-CHOP21 chemotherapy with cyclophosphamide dose adjustment for nephroprotection. He achieved complete remission with normalization of hematological parameters, improvement of kidney function, and reduction of proteinuria and albuminuria. This case shows the importance of considering alternative diagnoses in patients with recurrent chronic kidney disease and worsening nephrotic syndrome. Early diagnosis and treatment of mantle cell lymphoma can lead to favorable outcomes.

Mast cell sarcoma (MCS) is an extremely rare and aggressive form of mastocytosis characterized by highly atypical mast cells with local invasion, metastatic potential, and poor prognosis. MCS is predominantly a de novo process without recurrent molecular findings or predisposing lesions including various myeloid neoplasms. However, there have been rare case reports of MCS with preceding or concurrent systemic mastocytosis (SM) or cutaneous mastocytosis (CM), which is suggestive of an uncommon progression from SM/CM to MCS. We hereby report a case of MCS in an 84-year-old male with a KIT p.D816V mutation and concurrent SM. KIT p.D816V point mutation is well known as the canonical variant in SM. In our case, MCS with KIT p.D816V mutation is a unique finding in the setting of concurrent SM, highlighting the potential relatedness of these two entities and the progression from SM to MCS, a currently poorly understood phenomenon.

BRAF V600E mutations are frequently found in histiocytic/dendritic cell neoplasms such as Erdheim-Chester disease (ECD) and Langerhans cell histiocytosis (LCH), but few reports have also described BRAF mutations in Rosai-Dorfman disease (RDD), and even these cases may predominantly represent mixed histiocytosis. BRAF mutations have been studied in histiocytic/dendritic cell neoplasms and described to be associated with increased risk of relapse and long-term consequences, but few studies have examined BRAF V600E mutation in RDD, which is recognized as a neoplasm given the high frequency of MAPK pathway alterations. Here, we report a case of BRAF V600E-mutated RDD in a patient who presented with generalized lymphadenopathy. During our evaluation of this patient, we also found expression of PD-L1 in neoplastic histiocytes. During our review period, only few cases of RDD reported to harbor BRAF mutation or were evaluated for the expression of PDL1 by neoplastic cells. Given the potential challenges in distinguishing RDD from other histiocytic/dendritic cell neoplasms, including mixed histiocytosis with similar clinicopathological manifestations, we will discuss the current state of knowledge regarding the frequency and clinical impact of BRAF V600E in RDD, as well as the role of BRAF mutations in RDD pathogenesis. Distinction of BRAF V600E mutated histiocytic/dendritic cell neoplasms requires consideration of distinctive histopathological and immunophenotypic findings in appropriate clinical and radiologic setting. Given the increasing use of BRAF inhibitors as well as checkpoint blockade inhibitors to treat a number of cancers, we will discuss the clinical implications of the presence of BRAF V600E mutation and PD-L1 expression in RDD.

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.