Multinucleated Tumor Research Articles

MAD::NUT-fusion sarcoma: A sarcoma class with NUTM1, NUTM2A and NUTM2G fusions and possibly distinctive subtypes.

NUT-fusion-associated cancers are heterogeneous and include NUT carcinoma and an emerging group with non-BRD4/BRD3/NSD3 fusion partners. Here, we characterized 11 tumors harboring MAD::NUT-fusions (10/11 in females; median age: 48 yr; range: 1-67 yr), all histologically sarcomas. Eight cases were identified via sequencing database review and three were diagnosed prospectively. Eight patients (73%) presented with multifocal disease, including six with disseminated peritoneal tumors; three (27%) presented with solitary colonic, pulmonary, or orbital masses. Nine tumors (82%) harbored NUTM1 fusions, with MXI1 (5/9; 56%), MXD4 (2/9; 22%), and MGA (2/9; 22%). One tumor each harbored MXI1::NUTM2A and MXD4::NUTM2G. The nine MXD4/MXI1-rearranged sarcomas were high-grade, with epithelioid-to-spindle-cell cytomorphology, amphophilic cytoplasm, vesicular nuclei, and prominent nucleoli. Histologic features included infiltrative growth (7/7 assessable tumors), rhabdoid morphology (7/9; 78%), prominent collagen (3/9; 33%), multinucleated tumor cells (2/9; 22%), and myxoid stroma (1/9, 11%). MXD4/MXI1-rearranged sarcomas expressed desmin (3/7; 43%), and keratin(s) (3/7; 43%), and not p63 (6 tumors), CD34 (5), or S-100 (5). The adult MGA::NUTM1-fusion sarcoma exhibited some cytologic overlap with MXD4/MXI1-rearranged sarcomas but showed lower-grade myxoid spindle cell regions, microcystic spaces, and S-100 expression. The pediatric MGA::NUTM1-fusion sarcoma was low-grade with CD34/S-100 co-expression. Immunohistochemistry (IHC) demonstrated NUTM1 expression in NUTM1-rearranged sarcomas (5/5), and weak and no expression in NUTM2A- and NUTM2G-rearranged sarcomas, respectively. Gene expression profiling demonstrated sarcomas with MXD4/MXI1::NUTM1/NUTM2A/NUTM2G fusions clustered separately from NUT carcinoma. Follow-up was available for nine patients (82%; median: 1.8 yr; range: 2 mo-8.2 yr). Four of seven patients with MXD4/MXI-rearranged sarcomas died of disease (median: 1.3 yr; range: 5 mo-4.8 yr), one entered hospice at two months, and one was alive with pericardial masses at 2.8 years. The adult with the MGA::NUTM1-fusion sarcoma died of other causes at 4.5 years; the child was alive without disease at 11 months. We conclude that MAD::NUT-fusions define a sarcoma class distinct from NUT carcinoma. Among this group, MGA::NUTM1-fusion sarcomas might represent a distinctive subset. NUTM1 IHC does not reliably detect NUTM2A/NUTM2G-rearranged sarcomas.

Classic Hodgkin lymphoma: Pathobiological features that impact emerging therapies.

Classic Hodgkin lymphoma (cHL) is defined by distinctive Hodgkin Reed-Sternberg (HRS) cells, which are CD30+/CD15+ multinucleated tumor cells lacking typical B-cell markers. These cells comprise <5% of tumor mass but orchestrate an extensive immunosuppressive tumor microenvironment (TME). Classic HL was curable with radiation therapy and multi-agent chemotherapy. Despite high cure rates, treatment-related toxicities remain significant. The goals of multimodality therapy are to achieve a cure while minimizing treatment-associated toxicity. Advances in molecular insights into HRS cells have led to transformative therapies, including checkpoint inhibitors, antibody-drug conjugates like brentuximab vedotin, which have shown remarkable efficacy, especially in relapsed or refractory disease. However, challenges persist due to the heterogeneity of cHL, driven by the complex biology of HRS cells and their surrounding tumor microenvironment. Novel approaches such as single-cell RNA sequencing and circulating tumor DNA profiling provide promising strategies to address these challenges. This review examines the origin, morphology, phenotype, and genetic profiles of HRS cells, highlighting key pathobiological features, including biomarkers and Epstein-Barr Virus involvement. It also explores the biological mechanisms underlying HRS cell survival and evaluates standard and emerging therapies, offering insights into the rationale for novel treatment strategies.

Clear cell stromal tumor of the lung: Report of 3 cases with emphasis on multifocal tumors.

We describe 3 patients with clear cell stromal tumor (CCST) of the lung, all of whom presented with multifocal disease. The patients were 2 men and 1 woman aged 47-58 years (mean, 54 years). Two patients had evidence of autoimmune disease and their pulmonary disease was an incidental finding; one patient presented with non-specific respiratory symptoms. Radiologic imaging revealed multiple pulmonary nodules in all patients. Histologically, the tumors were solid-cystic and composed of cytologically bland, medium-sized ovoid to spindle cells with eosinophilic to clear cytoplasm arranged in a subtle nested pattern. These tumor cells were set in a highly vascularized stroma. Occasional cytologic atypia with multinucleated tumor cells was noted but mitotic activity was low. An infiltrate of mixed inflammatory cells was apparent in all tumors. Immunohistochemical analysis demonstrated diffuse expression of vimentin and TFE3 in all cases. Next generation sequencing revealed the presence of YAP1::TFE3 fusion in 1/1 case. All patients have remained alive albeit with stable or progressive disease, 24-66 months after diagnosis. These cases highlight the existence of multifocal pulmonary CCST and seem to support the notion that multifocality in CCST may be associated with more protracted clinical course. Awareness of the existence of multifocal pattern is important for patient management and prognosis.

Multinucleated tumor cells and micropapillary morphology appear to be predictors of poor prognosis in renal cell carcinoma with papillary and oncocytic features

Renal cell carcinoma with papillary and oncocytic features (RCC-PO) are poorly understood, partially due to conflicting results in multiple studies. The histological features that predict behavior of RCC-PO have not been elucidated. The aim is to review clinicopathologic features and to correlate clinical outcomes of patients with RCC-PO to further expand our knowledge on these heterogeneous tumors. An archival search was done for “RCC” and “papillary,” and tumors with >50% papillary and oncocytic features were included. Clinicopathologic data including tumor size, grade, stage, molecular and immunohistochemical testing when performed, and follow-up data were collected. Using multivariate analyses, correlation between histological features, tumor stage and prognosis were analyzed. Sixty-one patients with RCC-PO were identified of which 49 (80%) were male with a median age of 65 (range: 36–93) years, and a mean tumor size of 5.2 (range: 1–21.5) cm. Micropapillary features were seen in 4, bizarre nuclei (at least 3 times larger or with irregular shape) in 6, multinucleated tumor cells (MTC) in 15, single or small clusters (SSC) (made of 2–3 tumor cells) located away from areas of necrosis in 16, and striking eosinophilic cytoplasmic inclusions in 3 tumors, respectively. Thirty-six (59%) tumors were high-grade (WHO/ISUP grade 3–4), and 23 (38%) had a high stage (≥pT3 or pN1). Tumors were positive for AMACR (15/16) and CK7 (13/17), with preserved FH (7/7) staining and were all negative for CD117 (0/7), ALK, TFE3, cathepsin K, Melan A, and HMB45 (0/4, each). Three tumors underwent chromosomal microarray (CMA) plus gene fusion assay, and FISH and germline testing for FLCN and MET gene alterations by PCR were done on 1 each. Ten (16%) patients had a local recurrence (LR) or metastasis after nephrectomy; 4 died of disease (2 had tumors with micropapillary features), with a median follow-up of 7 (range: 0.01–19) years. Tumors with micropapillary features showed significantly higher RCC-PO-related mortality (50% vs. 3.5%, p < 0.001). In multivariable analysis, SSC correlated with a higher stage (HR: 11.95; p = 0.005); micropapillary features (HR: 18.42; p = 0.017) and MTC (HR: 180.22; p = 0.036) with presence of metastasis/LR; and micropapillary features with a higher RCC-PO-related mortality (HR: 60.35; p = 0.036). RCC-PO are cytogenetically heterogeneous with overlapping features of various renal neoplasms. Micropapillary features and MTC appear to be independent predictors of poor outcomes in these tumors.

Rare Presentation of Extraskeletal Osteosarcoma Mimicking Phyllodes Tumor

Abstract Introduction/Objective A 57-year-old female presented with a palpable mass in the left breast, measuring up to 9 cm by ultrasound. core needle biopsy identified an atypical spindle cell lesion. The differential diagnosis included a metaplastic carcinoma, borderline phyllodes tumor, malignant phyllodes tumor with potential sarcomatous transformation. Methods/Case Report Histological examination of the tumor was performed, and immunohistochemical stains were conducted to characterize the lesion. Further consultation with a specialized pathologist at the University of Michigan was sought to confirm the diagnosis. Molecular analysis was performed to assess for specific genetic alterations and expression patterns. The histological examination revealed a proliferation of atypical spindle cells forming a fascicular and storiform pattern, with numerous large, pleomorphic, multinucleated tumor cells and a high mitotic rate. Immunohistochemical stains showed strong positivity for CD10 and vimentin, with focal weak expression for desmin, and negativity for a broad panel of cytokeratins and other markers. Consultation with Dr. Abbott at the University of Michigan supported the diagnosis of extraskeletal osteosarcoma. Molecular analysis revealed PD-L1 expression and absence of NTRK gene fusions. FISH analysis showed suggestive alterations including loss of BRAF gene, loss of MYC, and suggestive gains or polysomy of PTEN gene. Results (if a Case Study enter NA) NA Conclusion The case represents a rare presentation of extraskeletal osteosarcoma in the breast, with distinctive histological and immunohistochemical features. The comprehensive workup including histology, immunohistochemistry, and molecular analysis aids in accurate diagnosis and potential therapeutic implications. Further research may elucidate the underlying mechanisms and treatment options for this uncommon malignancy.

Pleomorphic Liposarcoma Cytologically Detected in Hemosiderotic Pleural Effusion: Pitfalls Mitigated by Cytologic Clues and Cellblock Immunocytochemistry.

Sarcomatous serous effusions are uncommon and diagnostically challenging. Dedifferentiated and pleomorphic liposarcomas are rare tumors in pleural effusions revealing highly pleomorphic tumor cells mimicking carcinoma, mesothelioma, melanoma, and other sarcomas. Hematothoracic effusions further complicate the cytologic diagnosis. Correct cytologic recognition is important. We report pleomorphic liposarcoma cytologically detected in effusion fluid in a 56-year-old man who presented with a massive unilateral pleural effusion. ThinPrep showed hemorrhagic effusion fluid characterized by lysed red blood cells, foamy macrophages, and siderophages intermixed with highly pleomorphic predominantly naked mononuclear and giant nuclei. The aggregated siderophages and vacuolated macrophages could be mistaken for tumor cells, whereas the bare nuclei may be missed as nonspecific degenerate changes. Cellblock sections showed highly pleomorphic mononuclear and multinucleated giant tumor cells with diagnostic lipoblasts, intermixed with foamy macrophages and siderophages. Cellblock immunocytochemistry showed staining for vimentin and S-100 protein in the tumor cells. Other lineage-specific immunomarkers were negative. CD68 and calretinin revealed frequent background macrophages and scarce mesothelial cells. The tumor cells were negative for MDM2 and CDK4. The entertained cytopathologic diagnosis was pleomorphic liposarcoma. Core needle biopsy was procured from the mass. The histopathologic features and immunoprofile of the tissue specimen matched the cytopathologic and immunocytochemical findings confirming the cytologic diagnosis of pleomorphic liposarcoma. Pleomorphic liposarcoma is an unexpected cytologically challenging finding in effusions, particularly when compounded by pitfalls introduced by hemosiderotic fluid. Attention to certain cytologic clues mitigate pitfalls. Cellblock is a valuable diagnostic tool when integrated with relevant negative and positive immunocytochemical markers.

Urothelial Carcinoma with Trophoblastic Differentiation-A Report with Review.

Urothelial carcinoma with trophoblastic differentiation is a rare type of urothelial carcinoma that poses a diagnostic challenge. A 50-year-old man presented with hematuria for 4 months duration. Ultrasonography examination showed polypoidal lesions along the right lateral wall and near the right vesicoureteric junction of the urinary bladder. The transurethral resection of the bladder tumor (TURBT) specimen showed marked necrosis and urothelial tumor cells arranged in nests, sheets, and papillae, admixed with multinucleated large cells. Deep muscle and extensive lymphovascular invasion were noted. The tumor cells were diffuse immunopositive for GATA3 and focal positive for p63 and SALL4. Large multinucleated tumor cells were immunopositive for β-hCG, GATA3, inhibin-α, and PLAP, focally positive for SALL4 while negative for p63. The patient denied further treatment and succumbed to the disease after 8 months of the TURBT procedure. We report a rare invasive urothelial carcinoma with trophoblastic differentiation and discuss the differential diagnosis and literature review.

Cytoplasmic PPARγ Significantly Correlates With P53 Immunohistochemical Expression and Tumor Size in Localized Tenosynovial Giant Cell Tumor.

Tenosynovial giant cell tumor (TGCT)is a monoarticular fibrohistiocytic benign or locally aggressive soft tissue tumor that originates from the synovium of joints, bursae, and tendon sheaths.It has an inflammatory neoplastic nature, with a clinical presentationranging from pain, swelling, stiffness, and limited range of movement to joint instability and blockage. Its uncommon incidence leads to a poorly understood pathogenesis. Localized formsof TGCT (LTGCT) can cause significant morbidity, interfere with daily patient activities, and decrease the patient's quality of life in challenging cases. This study aimed to investigate the immunohistochemical expression of PPARγ (peroxisome proliferator-activated receptor gamma) and P53 in LTGCT to understand the disease better and offer potential therapeutic targets. The study is cross-sectional, in which 27 LTGCT cases were collectedfrom the Pathology Department, Faculty of Medicine, Cairo University, Cairo, Egypt.Solitary and multiple LTGCT cases retrieved between January 2018 and December 2022 were included, and immunohistochemically stained with anti-PPARγ and P53 antibodies. The TGCT samples were excluded if they were insufficient for sectioning, processing, and interpretation, over-fixed, had process artifacts, or were of the diffuse TGCT type. Scoring of stain expression was performed by ImageJ (National Institutes of Health, Bethesda, MD) analysis using the threshold method and was expressed in percent area/high power field. Clinicopathological correlations were analyzed. All the 27 collected LTGCT cases were located in the small joints of patients' hands. Cases with solitary LGTCTs constituted 55.6%(n = 15), while 44.4% (n = 12) had multipleLTGCTs related to one affected site/case (e.g., multiple tumors in one finger). PPARγ was expressed in the cytoplasm of mononuclear and multinucleated tumor cells and foamy histiocytes, while P53 expression was mainly in mononuclear cells' nuclei. PPARγ significantly correlated with P53 expression (r = 0.9 and P = 0.000). PPARγ (r = 0.4 and P = 0.02) and P53 (r = 0.5 and P = 0.01) were positively correlated with tumor size. Only P53 expression was positively correlated with tumor multiplicity (r = 0.4 and P = 0.03). Using the receiver operating characteristic curve test, the P53 cutoff score detecting the multiplicity of TGCTs was ≥20.5%, with a 75% sensitivity and 80% specificity. PPARγ and P53 have a significant role in LTGCT growth, while P53 plays a role in tumor multiplicity. They can be possible targets in LTGCTs unfit for excision.

Icariside I reduces breast cancer proliferation, apoptosis, invasion, and metastasis probably through inhibiting IL-6/STAT3 signaling pathway.

Breast cancer is a common malignancy in women. More than 90% of breast cancer deaths are caused by metastasis. Epimedii Folium (EF) is a commonly used herb with anti-tumor benefits, but its underlying mechanisms and active components for breast cancer prevention are little understood. This study assessed the therapeutic role of Icariside I (ICS I) in Epimedium flavonoids (EF) on lung metastasis of breast cancer, including the underlying mechanism. Western blot, RT-qPCR, wound healing assay, colony formation assay, and flow cytometry were used to investigate the inhibition of breast cancer cells growth and migration by EF and ICS I through disrupting the IL-6/STAT3 pathway. Combined with 4T1 breast cancer model in mice, Western blot, RT-qPCR, Hematoxylin and Eosin staining, immunohistochemistry were used to evaluate the therapeutic role of ICS I in proliferation, apoptosis, invasion, and metastasis of breast cancer. EF can inhibit STAT3 phosphorylation and reduce the colony formation and migration of breast cancer cells. Detecting the active ingredients in EF, we found ICS I can reduce the activation of STAT3 in 4T1 breast cancer cells, impair colony formation and migration. Moreover, ICS I induced cells G1 phase arrest and modulated Cyclin D1, CDK4, bcl-2, and bax to inhibit proliferation and survival of breast cancer cells. Similarly, the in vivo studies demonstrated that ICS I significantly suppressed tumor development and lung metastasis in the 4T1 mouse model. Tumor cells in vehicle group were arranged in a spoke-like pattern with obvious heterogeneity, and multinucleated tumor giant cells were seen. But, the tumor cells in the ICS I group were disorganized and necrotic lysis was seen in some areas. In ICS I-treated group, tumors' STAT3 phosphorylation level, IL-6, Cyclin D1, CDK4, bcl-2, and vimentin expression were downregulated, bax and cleaved caspase 3 expression were upregulated. In the lung tissue, we could find less metastasis of breast cancer cells and less lung injury in the ICS I group. Besides, the expression of metastasis-related genes MMP9 and vimentin was decreased in the lung tissue of ICS I group. These findings suggest that ICS I can inhibit breast cancer proliferation, apoptosis, invasion and metastasis probably via targeting IL-6/STAT3 pathway. Therefore, ICS I has the potential to become an innovative therapeutic candidate to breast cancer prevention and treatment.

Environmental physical factors produce mitotic aberration and multicellularity in the ovarian cancer cell line SKOV3

The spread of ovarian cancer (OC) to the coelomic cavity triggers the secretion and accumulation of ascitic fluid (AF). Although its biochemical composition has been well studied, less is known about the implications of physical factors such as the pH and the mechanical properties of the AF for the malignancy of tumor cells. In this work, we investigated the effect of pH and the mechanical properties of AF on cell proliferation and mitotic morphology. We employed biopsies from patients with OC and the SKOV3 cell line as an in vitro model of OC with HeLa cells as controls. Sections of each tumor were stained with HE, analyzed, and related to clinical data. AF from patients with OC exhibited an alkaline pH (ranging from 7.3 to 7.8). Compared to control conditions, the 3 AFs significantly enhanced the proliferation of SKOV3 and HeLa cells. These effects were more pronounced at a more alkaline pH. In addition, we found that AFs have different densities that correlated with a significant increase in multinucleated tumor cells and severe morphological defects in cells undergoing mitosis. In agreement with these data, we found that higher concentrations of soft agar provoked significantly higher numbers of multinucleated and morphologically abnormal SKOV3 cells with no effect on HeLa cells.We conclude that an alkaline pH and greater rigidity could enhance the metastatic potential of OC cells. We propose that these two physical factors could be parameters of clinical importance as predictors of malignancy.

Uterine leiomyoma with bizarre nuclei – A series of four cases

Uterine leiomyoma is the most common benign mesenchymal tumor of the uterus occurring in females of reproductive age group and are derived from smooth muscle. Degenerative changes are usual in leiomyoma. There is a wide spectrum of morphological patterns in leiomyomas, among them 90% of leiomyomas are the conventional type or usual type. Leiomyoma with bizarre nuclei is an unusual variant of uterine leiomyoma with presence of marked nuclear atypia and pleomorphism. However, there is low mitotic activity (&amp;#60; 5 mitoses/10 high power fields), absence of tumor cell necrosis and intermixed normal spindled smooth muscle cells. The present study describes histopathological analysis of 4 cases of leiomyoma with bizarre nuclei. All these cases underwent abdominal hysterectomy for leiomyomas in the uterus. The age range was 47 to 52 years. On gross examination the cases had well-defined masses with grey white, whorled areas and microscopic impression was leiomyoma with bizarre nuclei. These cases had low mitotic activity ranging from 1 to 3/ 10 high power fields and absence of tumor necrosis. Ki 67 index was 0.5 -1.0%. Leiomyoma with bizarre nuclei can create a diagnostic dilemma due to marked nuclear atypia, multinucleated tumor cells and karyorrhectic cells resembling mitotic figures. Hence it is important to rule out more aggressive and malignant mesenchymal tumors.

Glioma arising in the setting of mismatch repair deficiency-rare or are we missing it?

Germline mutations in mismatch repair (MMR) genes (MLH1, MSH2, MSH6, PMS2) can be mono-allelic or biallelic, resulting in a Lynch syndrome (LS) or constitutional mismatch repair deficiency (CMMRD) syndrome respectively. Glioma arising in the setting of MMR deficiency is uncommon. We describe two pediatric patients with high-grade glioma (HGG) and associated MMR protein deficiency. On histomorphology both cases showed HGG with astrocytic morphology and prominent multinucleated tumor cells. On immunohistochemistry, the first case was negative for IDH1 p.R132H showed loss of ATRX and p53 positivity. The second case was positive for IDH1 p.R132H and p53, but showed retained expression of ATRX. The histomorphology in both cases and additionally IDH mutation with retained ATRX in the second case, prompted us to test for MMR protein deficiency which was carried out by immunohistochemistry (IHC). One case revealed an immunostaining pattern suggestive of CMMRD while the other was suggestive of LS. Both the cases showed good response to surgery and radio-chemotherapy in the follow-up available. Our cases highlight the importance of testing for MMR proteins by simple IHC, in the setting of appropriate clinical scenario, histopathological and immunohistochemical findings. The recognition of these tumors is extremely important to guide further treatment and prompt family screening.

Multinucleated tumor cells in clear cell renal cell carcinoma.

Multinucleated tumor cells (MTCs) in clear cell renal cell carcinoma (ccRCC) are not well understood. Our study included ccRCC cases in a single institution between 2010 and 2019. We classified MTC as MTC with degenerative atypia (MTCD), MTC with no anaplasia (MTCNA), and MTC with anaplasia (MTCA). Clinicopathologic characteristics and outcomes were compared between MTC groups. In all, 92 of 256 people (36%) with ccRCC had MTC. People with ccRCC with MTCD and those with ccRCC but no MTC had similar clinicopathologic characteristics and outcomes. Also, MTCNA and MTCA were associated with larger tumor size, advanced pathologic tumor stage, higher World Health Organization/International Society of Urologic Pathologists nuclear grade, and higher metastatic potential (P < .001 for each parameter). Overall, MTCA was associated with an increased rate of recurrence (P = .004), higher metastatic potential (P < .001), and shorter time to metastasis (P = .033), regardless of tumor stage. Univariate Cox regression revealed MTCNA as a significant predictor of metastasis at 5 years (hazard ratio [HR], 4.171; 95% CI, 1.934-8.998); moreover, MTCA was a significant predictor of recurrence (HR, 5.723; 95% CI, 2.495-13.124), metastasis (HR, 12.024; 5.966-24.232), and death (HR, 5.661; 95% CI, 2.688-11.924) at 5 years. Although MTCD may not be relevant in tumor grading, MTCNA and MTCA are associated with adverse outcomes.

Clear Cell Renal Cell Carcinoma With Syncytial-Type Multinucleated Giant Tumor Cells: A Clinicopathologic Study of 14 Cases.

The presence of syncytial-type multinucleated giant tumor cells with emperipolesis in clear cell renal cell carcinoma (RCC) is uncommon, with only 31 cumulative published cases to date. After a rereview of 125 clear cell RCC of World Health Organization/International Society of Urological Pathology grade 3 or 4, 14 clear cell RCCs with admixed syncytial-type giant cells (to our knowledge, the largest series to date) were found with a mean patient age of 67 years and with no sex difference (M = 7, F = 7). Mean tumor size was 7.3 cm. The syncytial-type giant cells comprised between 2% and 20% of the tumor and were present mainly around areas of necrosis. Five tumors were staged as pT1 or pT2, 8 as pT3, and 1 as pT4. Other findings included sarcomatoid differentiation (3/14), rhabdoid differentiation (4/14), and emperipolesis (12/14). Positive immunostains included keratin AE1/AE3 (13/13), carbonic anhydrase 9 and CD10 (12/14 each), vimentin (8/14), EMA (5/12), and alpha-methyacyl-CoA racemase (3/12). Keratin 7, keratin 20, human melanoma black 45, KIT, TFE3, cathepsin K, CD68, CD61, and beta human chorionic gonadotropin were negative. Six of 13 patients had recurrence or metastases during a mean follow-up time of 56 months. Four of 13 patients died of disease, 2 of 13 patients were alive with the disease, and 7 of 13 patients had no evidence of disease. Although the incidence of finding syncytial-type multinucleated giant tumor cells in clear cell RCC is low (approximately 1.2%), given that a subset of the patients showed poor outcomes while lacking other poor histologic parameters (eg, sarcomatoid or rhabdoid differentiation), it may be prudent to recognize and report this feature when encountered.

Hepatic Angiosarcomas With Sinusoidal Growth Patterns.

Hepatic angiosarcomas are aggressive malignant tumors of the liver with variable morphology. One of the rare morphologies is that of the sinusoidal growth pattern, which is challenging to diagnose because of its subtle imaging and morphologic findings. This retrospective study characterizes the clinical, histologic, and immunohistochemical features of sinusoidal hepatic angiosarcomas. Thirteen cases were included in the study, comprising 12 (92.3%) needle core biopsies and 1 wedge biopsy; one of the needle biopsies also had a subsequent resection specimen available for review. Multiple biopsies were needed to make the diagnosis in 4 cases. At least moderate sinusoidal dilatation was seen in 53.8% of cases. Increased cellularity within the sinusoids was seen at both low-power and high-power magnification (69.2% and 84.6%, respectively). Cytologic atypia ranged from mild to marked. Multinucleated tumor cells were present in most cases (10/13 cases) but were often sparse. Mitotic activity was identified in 5/13 cases. ERG immunostains were more reliable than CD31 and CD34 in identifying the tumor cells. Ki-67 proliferative index ranged from 5% to 30%. p53 immunostains were available in 9 cases and c-MYC in 7 cases; they were positive in 62.5% and 33.3% of cases, respectively and had a mutually exclusive staining pattern. In summary, this rare pattern of hepatic angiosarcoma is challenging to diagnose but has distinctive morphologic findings that can be supplemented with immunostains to establish the diagnosis.

Case Report of a Glioma Patient with Homozygous Missense Amino Acid Substitution in KDR Gene

AbstractGliomas are the most commonly seen cancers of the central nervous system with a variable genetic predisposition. Here, we report a homozygous missense variant in the KDR gene in a patient with recurrent glioma. The 35-year-old male patient was diagnosed with stage IV glioma with a recurrence after 10 years from a low-grade stage two glioma. The patient underwent a repeat right craniotomy and ventriculoperitoneal shunt placement. Biopsy of the lesion showed areas of necrosis with microvascular proliferation and multinucleated tumor cells. An in-depth analysis of NGS data comprising a multigene panel of 351 genes (Agilent Cancer Core Panel) found a homozygous missense variant in exon 25 of the KDR gene that resulted in a substitution of an amino acid glutamine for arginine at codon 1118. The KDR gene or VEGF2 receptor is a type III receptor tyrosine kinase of the VEGF gene involved in angiogenesis. We hypothesize that the variation in the KDR gene may have a role in the patient's transition from grade II to grade IV glioma. While the clinical relevance of this mutation is not clear, screening mutations in the protein tyrosine and serine/threonine kinase domain of the KDR will provide critical insights into the development and progression of glioma in the pediatric and adult populations.

High-grade B-cell lymphoma with MYC and BCL2 rearrangements with abundant multinucleated giant tumor cells.

High-grade B-cell lymphoma with MYC and BCL2 rearrangements with abundant multinucleated giant tumor cells.

P029: Are Reed-Sternberg cells stuck in mitosis by short nucleoplasmic bridges as a consequence of centromeric instability?

Background: Multinucleated giant tumor cells are frequently observed in lymph nodes of untreated lymphoma patients. Malignant Hodgkin lymphoma (HL) cells i. e. small Hodgkin and large bi- or multinucleated Reed-Sternberg (HRS) cells are characterized by genomic instability and downregulation of numerous key regulators of e.g. cell cycle, spindle apparatus, cytokinesis and cell lineage differentiation. So far, the formation of HRS cells remains obscure. We have demonstrated previously that telomere instability is involved in the proliferation of small cells into large binucleated cells. Here, we have used a collection of HL cell lines to analyze the successive steps involved in the transformation of the mononucleated into the multinucleated RS-like cells. Materials and Methods: Seven HL cell lines and 30 HL lymph nodes were used. Cytokinesis-block micronucleus assay and telomere and centromere staining followed by the M-FISH technique were employed to analyze chromosomal instability. DNA repair pathways were investigated. Results: We demonstrate that telomere dysfunction in HL cell lines is associated with the formation of dicentric chromosomes with both centromeres in close proximity, but also with a high rate of formation of micronuclei. Two morphologically different types of nucleoplasmic bridges (NPBs) were observed: (1) Long NPBs related to telomere dysfunction and chromosome fusions, and (2) short NPBs related to centromere breakpoints with configurations of cells looking like “stuck” together as binucleated cells. Short NPBs and binucleated cells were seen in the cultures of all HL cell lines. However, each HL cell line was characterized by an individual signature of the proportion of long and short NPBs, which correlated with centrosome amplification and formation of stable binucleated cells. Similar mechanisms were identified in HL patient lymph nodes prior to treatment, thus underscoring the biological significance of our findings in cell cultures. Transcriptome analysis confirmed the variations in the DNA repair pathways regarding the rate of large cells among the different HL cell lines. Conclusion: The formation of dicentric chromosomes related to centromere instability, and short NPBs were associated with the emergence of binucleated cells through different mechanisms. Our findings open a novel route to understanding the transition from mononucleated cells to multinucleated cells in HL and in other B-cell lymphomas.

Image analysis reveals differences in tumor multinucleations in Black and White patients with human papillomavirus-associated oropharyngeal squamous cell carcinoma.

Understanding biological differences between different racial groups of human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) patients, who have differences in terms of incidence, survival, and tumor morphology, can facilitate accurate prognostic biomarkers, which can help develop personalized treatment strategies. This study evaluated whether there were morphologic differences between HPV-associated tumors from Black and White patients in terms of multinucleation index (MuNI), an image analysis-derived metric that measures density of multinucleated tumor cells within epithelial regions on hematoxylin-eosin images and previously has been prognostic in HPV-associated OPSCC patients. In this study, the authors specifically evaluated whether the same MuNI cutoff that was prognostic of overall survival (OS) and disease-free survival in their previous study, TTR , is valid for Black and White patients, separately. We also evaluated population-specific cutoffs, TB for Blacks and TW for Whites, for risk stratification. MuNI was statistically significantly different between Black (mean, 3.88e-4; median, 3.67e-04) and White patients (mean, 3.36e-04; median, 2.99e-04), with p=.0078. Using TTR , MuNI was prognostic of OS in the entire population with hazard ratio (HR) of 1.71 (p=.002; 95% confidence interval [CI], 1.21-2.43) and in White patients with HR of 1.72 (p=.005; 95% CI, 1.18-2.51). Population-specific cutoff, TW , yielded improved HR of 1.77 (p=.003; 95% CI, 1.21-2.58) for White patients, whereas TB did not improve risk-stratification in Black patients with HR of 0.6 (p=.3; HR, 0.6; 95% CI, 0.2-1.80). Histological difference between White and Black patient tumors in terms of multinucleated tumor cells suggests the need for considering population-specific prognostic biomarkers for personalized risk stratification strategies for HPV-associated OPSCC patients.

A Case of Undifferentiated Pleomorphic Sarcoma of the Right Lower Extremity

Objective: To strengthen the understanding of the disease and treatment of undifferentiated pleomorphic sarcoma (UPS). Methods: The clinical data of an elderly male patient with UPS admitted to Hebei Provincial People’s Hospital in September 2020 were retrospectively analyzed, and relevant literatures were reviewed. Results: The patient was an elderly male, 74 years old. The color Doppler ultrasonography of the body surface mass showed a solid mass of subcutaneous soft tissue on the lateral side of the right thigh. Undirected arrangement, multinucleated tumor giant cells with strange shapes are seen, and mitotic figures are more common. Immunohistochemical staining: CKpan (-), Vimentin (+), Desmin (-), SMA (partial+), EMA (-), S100 (-), CD34 (vascular+), MyoD1 (-), Myogenin (-), Myoglobin (-), CD68 (-), Caldesmon (-), Ki-67 (about 40% active area). After six months of follow-up, no tumor recurrence was found. Conclusion: UPS is a rare malignant tumor in clinic. It has no specific clinical manifestations, imaging manifestations, histopathology and immunohistochemical staining. It is an exclusive diagnosis. Complete tumor resection is required, and pathological examination is the gold standard for diagnosis. Its long-term prognosis is relatively poor.