Profiles of genomic alterations in primary esophageal follicular dendritic cell sarcoma: A case report

One Health: Therapies Targeting Genetic Variants in Human and Canine Histiocytic and Dendritic Cell Sarcomas

The precise cause of HS/DCS is still unknown. The relatively low incidence in humans urges for an animal model with a high incidence to accelerate knowledge about genetics and optimal treatment of HS/DCS. Namely, until now, the therapies targeting genetic variants are still more experimental and sparsely used, while consensus is missing. In addition, the literature about variants and possible mutation-targeted therapies in humans and dogs consists mainly of case reports scattered throughout the literature. Therefore, an overview is provided of all currently known genetic variants in humans and dogs with HS/DCS and its subtypes, their possible mutation-targeted therapies, their efficacy, and a contemplation about the future. Several genetic variants have already been discovered in HS/DCS, of which many are shared between canine and human HS/DCS, but unique variants exist as well. Unfortunately, none of these already found variants seem to be specifically causal for HS/DCS, and the puzzle of its landscape of genetic variation is far from complete. The use of mutation-targeted therapies, including MAPK-/MEK-inhibitors and the future use of PTPN11-, CDK4/6- and PD-1-inhibitors, seems to be promising for these specific variants, but clearly, clinical trials are needed to determine optimal inhibitors and standardised protocols for all variants. It can be concluded that molecular analysis for variants and subsequent mutation-targeted therapy are an essential addition to cancer diagnostics and therapy. A joint effort of humans and dogs in research is urgently needed and will undoubtedly increase knowledge and survival of this devastating disease in dogs and humans.

MYC and TP53 Alterations but Not MAPK Pathway Mutations Are Common Oncogenic Mechanisms in Follicular Dendritic Cell Sarcomas

CONTEXT.—

Despite their stromal origin, follicular dendritic cells (FDCs) share many functions with hematopoietic system cells. FDC neoplasms are currently classified by the World Health Organization along with those of a histiocytic nature. However, the molecular alterations driving oncogenesis in FDC sarcomas (FDCSs) are beginning to be unveiled and do not seem to concur with those described in histiocytic neoplasms, namely MAPK pathway activation.

OBJECTIVE.—

To identify molecular alterations driving tumorigenesis in FDCS.

DESIGN.—

We investigated the role of MYC and TP53 in FDC-derived tumor oncogenesis and assessed comprehensively the status of the MAPK pathway in 16 FDCSs, 6 inflammatory pseudotumor (IPT)-like FDCSs, and 8 IPTs.

RESULTS.—

MYC structural alterations (both amplifications and rearrangements) were identified in 5 of 14 FDCSs (35.7%), all associated with MYC overexpression. TP53 mutations were identified in 4 of 14 FDCSs (28.6%), all of which displayed intense and diffuse p53 expression. None of these alterations were identified in any IPT-like FDCSs or in IPT cases. No MAPK pathway gene alterations were identified in any of the cases studied.

CONCLUSIONS.—

The presence of MYC and TP53 alterations and the lack of association with Epstein-Barr virus segregate classical FDCS from IPT-like FDCS, pointing at different oncogenic mechanisms in both entities. Our results suggest a possible oncogenic role of MYC and TP53 alterations in FDCS. The absence of MAPK pathway alterations confirms the lack of a significant role of this pathway in the oncogenesis of FDC-derived neoplasms.

Case report: Hepatic inflammatory pseudotumor-like follicular dendritic cell sarcoma: a rare case and review of the literature

Inflammatory pseudotumor-like follicular dendritic cell sarcoma (IPT-like FDCS) is a rare subtype of follicular dendritic cell sarcoma (FDCS) that primarily occurs in the liver and spleen. The etiology of IPT-like FDCS is unknown, and it has nonspecific clinical manifestations, imaging performance and laboratory test results. Recently, a patient with IPT-like FDCS was admitted to our hospital because of abdominal distension and anemia. Over the past 3 years, the patient has been followed up after a liver mass was found in a physical examination. The lesion gradually enlarged and caused compression symptoms. In November 2022, a tumor with a diameter of approximately 20 cm was found in the right posterior lobe of the liver after abdominal enhanced Magnetic resonance imaging (MRI) in our hospital. Liver tumor biopsy before the operation revealed a large number of hyperplastic plasma cells and a small number of spindle cells, and the spindle cells were atypical. After a complete examination, the patient underwent liver resection. Pathology after surgery confirmed liver IPT-like FDCS.

Extra-Nodal Follicular Dendritic Cell Sarcoma with Unusual Morphological Features and PDL1 Expression

Follicular dendritic cell (FDC) sarcoma, a rare tumor of FDCs, poses a diagnostic challenge due to its myriad morphologic and architectural patterns. We present a unique case of extra-nodal FDC sarcoma occurring in a 28-year-old gentleman who presented with multiple pelvic, peritoneal and retroperitoneal soft tissue, and axial skeletal lesions. The tumor was composed of islands and trabeculae of epithelioid cells with interspersed lymphocytes against a background of abundant myxoid matrix. On immunohistochemistry, in addition to the CD21, the tumor was positive for GATA3, inhibin, and programmed death-ligand 1 (PDL1), which have been rarely reported previously in FDC sarcoma. The patient underwent surgical excision of the tumor and was later offered immunotherapy. He has been disease-free for 2 years following immunotherapy. Our case highlights the potential role of immune checkpoint inhibitors in treating FDC sarcoma, which show immuno-expression of PDL1.

Follicular dendritic cell sarcoma

Follicular dendritic cells (FDC) are mesenchymal-derived dendritic cells located in B-follicles where they play a pivotal role in triggering and maintaining B-cell adaptive immune response. In 1986 Dr. Juan Rosai first reported a series of neoplasms showing features of FDC and defined it as Follicular Dendritic Cell Tumor, subsequently renamed as "sarcoma" (FDCS). In its seminal and subsequent articles Rosai and colleagues highlighted the heterogeneous microscopic appearance of FDCS and its immunohistochemical and ultrastructural features.

FDCS mostly occurs in extranodal sites (79.4% of cases) and lymph nodes (15.1%); in about 7%-10% of cases it is associated with hyaline-vascular Castleman disease. Given its significant growth pattern and cytological variability, FDCS can be confused with various neoplasms and even inflammatory processes. The diagnosis requires the use of a broad spectrum of FDC markers (e.g. CD21, CD23, CD35, clusterin, CXCL13, podoplanin), particularly considering that tumor antigen-loss is frequent. The inflammatory-pseudotumor-like (IPT-like) variant of FDCS, in addition to its peculiar histopathological and clinical features, is characterized by positivity of tumor cells for Epstein-Barr virus, representing a diagnostic requisite.

No distinctive genetic and molecular anomalies have been identified in FDCS. It often carries an aberrant clonal karyotype and chromosomal structural alterations, frequently involving onco-suppressor genes. Direct or next generation sequencing showed alterations on genes belonging to the NF-κB regulatory pathway and cell-cycle regulators. In contrast to hematopoietic-derived histiocytic and dendritic cells tumors, FDCS typically lacks mutations in genes related to the MAPK pathway.

FDCS recurs locally in 28% and metastasizes in 27% of cases. Extent of the disease, surgical resectability and histopathological features are significantly associated with the outcome. IPT-like FDCS behaves as an indolent tumor, even if it often recurs locally over years.

Complete surgical excision is the gold standard of treatment. Data on targeted therapies (e.g.: tyrosine kinase inhibitors) or immune checkpoint inhibitors are very limited and responses are variable. A better understanding of the molecular drivers of this tumor may lead to potential new therapeutic strategies.

Clinicopathological characteristics of extranodal follicular dendritic cell sarcoma: A report of two cases

Follicular dendritic cell sarcoma (FDCS) is an extremely rare tumor, which mainly originates from FDCs in the lymph nodes. Sometimes FDCS can arise from outside the lymph nodes due to the existence of acquired lymphoid tissue, which becomes the histological basis of the tumor. The diagnosis of FDCS, particularly extranodal FDCS, presents a challenge for pathologists and hematopathologists. The present study presents two cases of extranodal FDCS based on clinical features and histomorphology. Soft tissue of the chest wall was involved in case 1 and right tonsil tissue in case 2. Case 1 underwent surgery, and was in good health post-operatively. During the 5-month post-operative follow-up period, the patient was healthy in all respects. Case 2 received surgery combined with radiotherapy, and the follow-up data reported that the patient remained alive, without signs of recurrence or metastasis during the 4-month post-operative follow-up period. Additionally, a total of 102 cases of extranodal FDCS were retrieved from the literature, which were extracted and reviewed carefully. The rates of recurrence, metastasis and mortality were 14.63 (12/82), 17.07 (14/82) and 8.29% (15/82), respectively. The overall survival rates of the 102 cases, showing 2-year total survival rates, were 70%, the same with that of 5-year total survival rates. The 2-year tumor-free total survival rates were 68%, and the 5-year equivalents were 32%. Female patients had a poorer prognosis than male patients (P<0.05). Kaplan-Meier estimation presented no statistically significant differences between disease-free survival rates or overall survival rates and age, tumor size or treatment (P>0.05).

Epstein-Barr virus-negative inflammatory pseudotumor-like variant of follicular dendritic cell sarcoma of the liver: A case report and literature review

Follicular dendritic cell sarcoma (FDCS) can be divided into the conventional type, and the inflammatory pseudotumor (IPT)-like variant type. Epstein-Barr virus (EBV) infection is considered to be closely associated with the pathogenesis of IPT-like variant of FDCS. Hepatic FDCS has an exceedingly low incidence of only 29 cases reported, with most of these tumors being classified as the IPT-like type. We report a case of an IPT-like variant of FDCS of the liver in a 61-year old man who presented with no marked symptoms. The patient underwent laparoscopic surgery for the mass and was well during a 13-month follow-up periods. The postoperative pathological examination found a proliferation of spindle cells and a diffuse infiltration of inflammatory cells within the tumor. Immunohistochemistry revealed that neoplastic cells were positive for CD23, clusterin, fascin, and PD-L1, and weakly positive for CD35, SMA, and D2-40. The infiltrating lymphocytes were strongly positive for PD1, and IgG4-positive plasma cells were less than 10 cells/high-power field. In situ hybridization for Epstein-Barr virus encoded RNA (EBER) was negative. To our knowledge, the present case is the second case of hepatic IPT-like variant of FDCS without EBV involvement, indicating that EBV infection is not an absolute prerequisite for a diagnosis of the IPT-like variant of FDCS.

Histiocytic and dendritic cell neoplasms: Reappraisal of a Japanese series based on t(14;18) and neoplastic PD-L1 expression

Histiocytic and dendritic cell (H/DC) neoplasms are heterogeneous, originating from myeloid- or stromal-derived cells. Multiple reports describe the cross-lineage transdifferentiation of neoplastic B cells into H/DC neoplasms. Most such cases are from Western countries, and rarely from Japan or East Asia. Here we report 17 cases of H/DC neoplasms in Japanese patients, with analysis of t(14;18) by fluorescence in situ hybridization, and of neoplastic programmed death-ligand 1 (PD-L1) expression by immunostaining (clones SP142, E1J2J, and 28-8). These 17 cases were diagnosed according to the 2017 World Health Organization (WHO) classification, and included two histiocytic sarcomas (HS), two interdigitating cell (IDC) sarcomas, one Langerhans cell sarcoma, two dendritic cell sarcomas, and 10 follicular dendritic cell (FDC) sarcomas. No case had any past history of follicular lymphoma (FL). Two cases of HS and one IDC sarcoma, all of which were myeloid-driven, were found to exhibit t(14;18). In the latter case, at 30 months after IDC sarcoma diagnosis, FL development was detected. Three (30%) FDC sarcoma cases exhibited neoplastic PD-L1 expression with all the three PD-L1 antibody clones. This is the first report of t(14;18) and neoplastic PD-L1 expression on H/DC neoplasms among Japanese patients, each of which appeared to be associated with HS and FDC sarcoma, respectively.

Esophageal intramural squamous cell carcinomas presenting as subepithelial lesions removed by endoscopic submucosal dissection: Two case reports

INTRODUCTION

Esophageal subepithelial lesions (SELs) are rare, and the majority of them are benign. SELs are often covered with normal mucosa, thereby resulting in some malignant SELs to be easily missed or misdiagnosed. We report 2 cases of esophageal intramural squamous cell carcinomas (SCCs) that presented as SELs and were endoscopically removed.

PATIENT CONCERNS

Case 1 is a 63-year-old man with abdominal distension; case 2 is a 65-year-old man with increasing dysphagia for 2 months.

DIAGNOSIS

In case 1, endoscopy showed a 1.5-cm mucosal eminence with normal overlying mucosa. Endoscopic ultrasound (EUS) revealed that it might be derived from the muscularis mucosa or submucosa. In case 2, endoscopy revealed a 1.2-cm hemispherical lesion covered with smooth mucosa. Furthermore, EUS revealed that this lesion might be derived from the submucosa.

INTERVENTIONS

In both cases, the lesions were removed by endoscopic submucosal dissection (ESD). Pathological examination revealed esophageal SCC nests with intramural growth patterns.

OUTCOMES

The first patient underwent postoperative radiotherapy, whereas the second patient did not receive any additional treatment. Both patients agreed to regular follow-up, and no tumor recurrence or metastasis was observed.

CONCLUSION

First, not all esophageal SELs are benign, and a small number of SELs can be malignant. Second, these cases illustrate the value of newer endoscopic techniques, especially ESD. Thus, it is important to be alert when visualizing the esophagus for the possibility of a subtle SEL so that further evaluation and treatment, if necessary, can be undertaken, ideally with a less invasive approach afforded by ESD.

Genetic Heterogeneity of Esophageal Squamous Cell Carcinoma with Inherited Family History

Background

Esophageal squamous cell carcinoma (ESCC) is a common malignant tumor with significant geographical variation and familial aggregation. However, the potentially different mechanisms underlying tumorigenesis in patients with ESCC with and without a family history of the disease remain unclear. In this study, the genes mutated in familial and nonfamilial ESCC were analyzed. Further, we aimed to explore the genes related to ESCC and attempt to identify potential patients in families with a history of ESCC.

Methods

Next-generation sequencing technology was used to examine germline mutations and mutation profiles in 36 matched tumor-normal ESCC specimens. Additionally, tumor mutational burden (TMB) values were measured in two cohorts.

Results

We identified four novel germline mutations in patients with familial ESCC, in BAX (c.121dupG: p.E41G), CDKN2A (c.374dupA: p.D125E), TP53 (c.856G>A: p.E286K), and CHEK1 (c.923+1G>A). Mutation profiles revealed that patients with and without a family history of ESCC had similar high-frequency gene mutation profiles, among which TP53 was the most commonly mutated gene. Additionally, tumor-specific mutated genes in patients with a positive family history of ESCC were APC, AKT3, DPYD, EP300, NFE2L2, PPP2R1A, RUNX1, and VEGFA, while those in patients without a family history of ESCC were CXCR4, PIK3R2, SMARCA4, and TTF1. Moreover, patients with positive family history had significantly higher TMB values (7.8 ± 4.1 vs 5.0 ± 2.4, for patients with and without a family history, respectively; P = 0.038).

Conclusion

Our results identified mutation profiles in patients with familial and nonfamilial ESCC, and identified germline mutations in patients with positive history. TMB values may be informative for immunotherapy approaches in familial ESCC.

Fine needle aspiration of an intranodal follicular dendritic cell sarcoma: A case report with molecular analysis and review of the literature

Follicular dendritic cell sarcoma (FDCS) is a rare malignant neoplasm of follicular dendritic cell origin which can present a diagnostic challenge. Due to the rarity of this neoplasm, its molecular pathogenesis has not been fully elaborated. A previous series of 13 cases reported that 38% contained mutations of genes encoding proteins involved in negative regulation of NF-κB. NF-κB is a family of transcription factors regulated through multiple cellular processes known as the canonical and noncanonical pathways. Here we present the case of a 62-year-old man who presented with abdominal pain and systemic symptoms and was found to have a mass in the porta hepatis. Fine needle aspiration cytology demonstrated a spindle cell neoplasm with vesicular chromatin and prominent nucleoli with admixed lymphocytes. Surgical resection showed an intranodal, 7.3 × 5.5 × 3.5 cm, solid mass composed of plump, spindle to histiocytoid cells with ovoid nuclei and small, prominent nucleoli arranged in a whorled and fascicular pattern. The lesional cells stained positively for CD21, CD23, and CD35 by immunohistochemistry, consistent with a diagnosis of FDCS. Next-generation sequencing revealed pathologic mutations in three genes involved in NF-κB regulation pathways: NFKBIA, TNFAIP3, and TRAF3. A pathologic TP53 mutation was also identified. This case report supports prior associations of the NF-κB pathway dysregulation and FDCS. Additionally, it is the first reported FDCS case with TRAF3 mutation as well as the first reported case to suggest disruption in both the canonical and noncanonical NF-κB pathways in the same lesion.