Myeloid Sarcoma of the Colon Initially Presenting as a Paracolic Abscess in a Patient with Relapsed Acute Myeloid Leukemia.

Myeloid sarcoma, a rare extramedullary manifestation of acute myeloid leukemia (AML), can occur in various anatomic sites but seldom involves the gastrointestinal tract. We report the unusual case of a 49-year-old man with a history of AML who initially presented with abdominal pain and imaging findings suggestive of a paracolic abscess. However, the lesion rapidly progressed to a large descending colon mass with peritoneal involvement over five weeks. Surgical resection and histopathological examination confirmed a diagnosis of myeloid sarcoma. This case highlights the potential of myeloid sarcoma to mimic an inflammatory colonic process at initial presentation prior to manifesting as an overt mass lesion. Although exceedingly rare, myeloid sarcoma should be considered in patients with a history of AML presenting with colon lesions, particularly in those with an aggressive clinical course. Early recognition may expedite appropriate treatment and prevent unnecessary procedures. This report also underscores the importance of correlating imaging findings with clinical history and histopathology findings to establish an accurate diagnosis.

Utilizing Immunoglobulin G4 Immunohistochemistry for Risk Stratification in Patients with Papillary Thyroid Carcinoma Associated with Hashimoto Thyroiditis.

BACKGRUOUND: Hashimoto thyroiditis (HT) is suspected to correlate with papillary thyroid carcinoma (PTC) development. While some HT cases exhibit histologic features of immunoglobulin G4 (IgG4)-related disease, the relationship of HT with PTC progression remains unestablished. METHODS: This cross-sectional study included 426 adult patients with PTC (≥1 cm) undergoing thyroidectomy at an academic thyroid center. HT was identified based on its typical histologic features. IgG4 and IgG immunohistochemistry were performed. Wholeslide images of immunostained slides were digitalized. Positive plasma cells per 2 mm2 were counted using QuPath and a pre-trained deep learning model. The primary outcome was tumor structural recurrence post-surgery. RESULTS: Among the 426 PTC patients, 79 were diagnosed with HT. With a 40% IgG4 positive/IgG plasma cell ratio as the threshold for diagnosing IgG4-related disease, a cutoff value of >150 IgG4 positive plasma cells per 2 mm2 was established. According to this criterion, 53% (43/79) of HT patients were classified as IgG4-related. The IgG4-related HT subgroup presented a more advanced cancer stage than the IgG4-non-related HT group (P=0.038). The median observation period was 109 months (range, 6 to 142). Initial assessment revealed 43 recurrence cases. Recurrence-free survival periods showed significant (P=0.023) differences, with patients with IgG4 non-related HT showing the longest period, followed by patients without HT and those with IgG4-related HT. CONCLUSION: This study effectively stratified recurrence risk in PTC patients based on HT status and IgG4-related subtypes. These findings may contribute to better-informed treatment decisions and patient care strategies.

FLI-1 is expressed in a wide variety of hematolymphoid neoplasms: a special concern in the differential diagnosis.

Friend Leukemia Virus Integration 1 (FLI-1) is a member of E26 transformation-specific family of transcription factors that participates in hematopoietic and vascular endothelial cell development. Immunohistochemical detection of FLI-1 has been widely used to diagnose vascular tumors or, more evidently, Ewing's sarcoma. However, the expression pattern of FLI-1 in hematolymphoid neoplasms remains unclear. Therefore, in this study, we aimed to investigate the expression of FLI-1 in these tumors, focusing on high-grade lesions, which presents a diagnostic challenge by mimicking Ewing's sarcoma. We evaluated the expression FLI-1 in various types of lymphoid and plasmacytic tumors, including 27 plasmablastic lymphomas, 229 diffuse large B-cell lymphomas, 22 precursor T- or B-lymphoblastic lymphomas, 24 angioimmunoblastic-type nodal T-follicular helper cell lymphomas, 52 peripheral T-cell lymphomas, NOS, 18 Burkitt lymphomas, 18 non-gastric lymphomas of mucosa-associated lymphoid tissue, 38 chronic lymphocytic leukemia/small lymphocytic lymphomas, 15 mantle cell lymphomas, 23 gastric MALT lymphomas, 50 plasma cell myelomas, and 38 follicular lymphomas. We calculated the H-scores of FLI-1 immunostaining, ranging from 0 to 200, and used the scores to analyze the clinicopathological significance of FLI-1 statistically. FLI-1 was expressed to varying degrees in all types of hematological tumors. FLI-1 expression was detected in 84.1% of patients (466/554). FLI-1 was highly expressed in precursor T- or B-lymphoblastic lymphomas. Follicular lymphomas exhibited low FLI-1 expression. In plasmablastic lymphoma, 85.2% of the patients were focally positive for FLI-1. FLI-1 expression did not correlate with clinicopathological variables, such as demographic data or disease stage, in patients with plasmablastic lymphoma and diffuse large B-cell lymphoma. However, FLI-1 overexpression was associated with poorer overall survival in patients with plasmablastic lymphoma. This study demonstrates that FLI-1 is expressed in various hematolymphoid neoplasms. FLI-1 expression can lead to diagnostic confusion, especially in small blue round cell tumors, such as lymphoblastic lymphoma, plasmablastic lymphoma, and plasma cell myeloma, when distinguishing tumors positive for CD99 and CD56 without CD3, CD20, or CD45. Our findings also suggested the possibility of FLI-1 as a potential prognostic biomarker for plasmablastic lymphoma.

Long-term Clinical Outcomes of Optimizing Combination Therapy for Primary Pulmonary Mucosa-associated Lymphoid Tissue Lymphoma: A Retrospective Study.

INTRODUCTION: Pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma progresses with advancing disease stage. However, no standard treatment approach has been established. This single-center retrospective study evaluated clinical and radiological characteristics, treatment modalities, and long-term prognosis of pulmonary MALT lymphoma. METHODS: The study included 42 patients diagnosed with pulmonary MALT lymphoma between October 2004 and July 2019. Primary therapeutic modalities were determined using modified Ann Arbor staging. Therapeutic response was evaluated via computed tomography and laboratory analyses every 6 months for 5 years. Radiological findings were categorized based on the Lugano classification as complete response (CR), partial response, stable disease (SD), or progressive disease. RESULTS: Initial treatment included observation (n=2), surgical resection (n=6), or systemic chemotherapy (n=34). Patients treated surgically had localized disease and achieved initial and long-term CR. Of the 34 patients who underwent chemotherapy, 30 achieved CR, 2 achieved SD, and 2 died. Overall and progression-free survival (PFS) rates were 93.9% and 54.3%, respectively. Multivariate analysis indicated that PFS was lower in patients with modified Ann Arbor stage III-IV lymphoma and those who did not achieve CR. CONCLUSIONS: Optimized treatment based on anatomical location, pulmonary function, and disease stage can improve long-term survival in patients with pulmonary MALT lymphoma.

Prognostic Value of FDG PET/CT in Patients with Nodal Peripheral T-Cell Lymphoma.

This study evaluated the prognostic significance of FDG PET/CT in patients with nodal peripheral T-cell lymphoma (PTCL). We retrospectively reviewed patients with histologically confirmed nodal PTCL who underwent FDG PET/CT at baseline, after three cycles of first-line chemotherapy (interim), and at the end of therapy. Response was assessed visually using the Deauville 5-point scale (D5PS); scores of 1, 2, and 3 were considered PET-negative, and scores of 4 and 5 were considered PET-positive. The associations between FDG PET/CT findings and survival were assessed using Cox regression analysis. A total of 79 patients (44 males and 35 females; median age 56 years) were included in this study. In response assessment, 17 (22%) had an interim PET-positive result and 10 (13%) had an end-of-therapy PET-positive result. During a median follow-up of 50 months, 37 patients (47%) presented with disease progression and 30 patients (38%) died. The estimated 5-year progression-free survival (PFS) and overall survival (OS) were 57% and 64%, respectively. An interim PET-positive result was the only significant indicator of PFS. Higher International Prognostic Index and end-of-therapy PET-positive result were significant independent prognostic factors of OS. Interim and end-of-therapy FDG PET/CT responses based on D5PS are meaningful in predicting the outcomes of patients with nodal PTCL.

A stepwise approach to fine needle aspiration cytology of lymph nodes.

The cytological diagnosis of lymph node lesions is extremely challenging because of the diverse diseases that cause lymph node enlargement, including both benign and malignant or metastatic lymphoid lesions. Furthermore, the cytological findings of different lesions often resemble one another. A stepwise diagnostic approach is essential for a comprehensive diagnosis that combines: clinical findings, including age, sex, site, multiplicity, and ultrasonography findings; low-power reactive, metastatic, and lymphoma patterns; high-power population patterns, including two populations of continuous range, small monotonous pattern and large monotonous pattern; and disease-specific diagnostic clues including granulomas and lymphoglandular granules. It is also important to remember the histological features of each diagnostic category that are common in lymph node cytology and to compare them with cytological findings. It is also essential to identify a few categories of diagnostic pitfalls that often resemble lymphomas and easily lead to misdiagnosis, particularly in malignant small round cell tumors, poorly differentiated squamous cell carcinomas, and nasopharyngeal undifferentiated carcinoma. Herein, we review a stepwise approach for fine needle aspiration cytology of lymphoid diseases and suggest a diagnostic algorithm that uses this approach and the Sydney classification system.

Consensus Definition of Blood Samples from the Subcategorized Normal Controls in the Korea Biobank Network.

A control group is defined as a group of people used for comparison. Depending on the type of study, it can be a group of healthy people or a group not exposed to risk factors. It is important to allow researchers to select the appropriate control participants. The Korea Biobank Project-sponsored biobanks are affiliated with the Korea Biobank Network (KBN), for which the National Biobank of Korea plays a central coordinating role among KBN biobanks. KBN organized several working groups to address new challenges and needs in biobanking. The "Normal Healthy Control Working Group" developed standardized criteria for three defined control groups, namely, normal, normal-plus, and disease-specific controls. Based on the consensus on the definition of a normal control, we applied the criteria for normal control participants to retrospective data. The main reason for exclusion from the "Normal-plus" group was blood test results beyond 5% of the reference range, including hypercholesterolemia. Subclassification of samples of normal controls by detailed criteria will help researchers select optimal normal controls for their studies.

Validation of a Machine Learning Expert Supporting System, ImmunoGenius, Using Immunohistochemistry Results of 3000 Patients with Lymphoid Neoplasms.

(1) Background: Differential diagnosis using immunohistochemistry (IHC) panels is a crucial step in the pathological diagnosis of hematolymphoid neoplasms. In this study, we evaluated the prediction accuracy of the ImmunoGenius software using nationwide data to validate its clinical utility. (2) Methods: We collected pathologically confirmed lymphoid neoplasms and their corresponding IHC results from 25 major university hospitals in Korea between 2015 and 2016. We tested ImmunoGenius using these real IHC panel data and compared the precision hit rate with previously reported diagnoses. (3) Results: We enrolled 3052 cases of lymphoid neoplasms with an average of 8.3 IHC results. The precision hit rate was 84.5% for these cases, whereas it was 95.0% for 984 in-house cases. (4) Discussion: ImmunoGenius showed excellent results in most B-cell lymphomas and generally showed equivalent performance in T-cell lymphomas. The primary reasons for inaccurate precision were atypical IHC profiles of certain cases, lack of disease-specific markers, and overlapping IHC profiles of similar diseases. We verified that the machine-learning algorithm could be applied for diagnosis precision with a generally acceptable hit rate in a nationwide dataset. Clinical and histological features should also be taken into account for the proper use of this system in the decision-making process.

Diagnosis, treatment, and prognosis of primary intraocular lymphoma: Single-center real-world clinical experience.

BACKGROUND: The diagnosis and management of primary intraocular lymphoma (PIOL) remain challenging. This study identified factors indicative of PIOL, described treatment outcomes, and determined modalities to prevent relapse. METHODS: We included 21 PIOL-diagnosed patients, seven via cytology, 12 via genetic evaluation, and two via interleukin (IL) level measurements, who underwent vitrectomy and received local intravitreal methotrexate (IV-MTX) injection. Clinical outcomes, including treatment response and relapse, were compared between patients receiving IV-MTX alone (n = 13) or IV-MTX with systemic high-dose methotrexate (HD-MTX) as prophylaxis (n = 8). RESULTS: Twelve ophthalmologic and eight central nervous system (CNS) relapse cases within a median of 20.3 and 11.6 months were shown, regardless of the treatment modalities, with a median progression-free survival of 21.3 (95% confidence interval, 9.5-36.7) months. There was no difference in demographic characteristics between the two groups, except with the poorer performance status in patients in the HD-MTX prophylaxis group. Furthermore, patients demonstrated rapid elevations in the vitreous fluid IL-10/IL-6 cytokine ratio before ophthalmologic and CNS relapse. Therefore, diagnosis should be based on clinical signs and assisted by vitrectomy, cytologic, molecular, and cytokine studies. CONCLUSION: For PIOL, aggressive systemic treatment equivalent to that of primary CNS lymphoma (PCNSL) is recommended because solely HD-MTX did not prevent or delay CNS relapse. To prevent PIOL relapse in the CNS efficiently, prospective trials with large numbers of patients and advanced therapeutic regimens are necessary. Furthermore, regular clinical follow-up is crucial, and the IL-10/IL-6 ratio can help evaluate relapse promptly.