Characteristics, management, and outcomes of patients with follicular dendritic cell sarcoma

Progressive abdominal pain with acute exacerbation due to retroperitoneal follicular dendritic cell sarcoma: a case report with targeted genomic sequencing analysis

BACKGROUND

Follicular dendritic cell sarcoma (FDCS) is a rare malignancy that arises from follicular dendritic cells and typically presents as a slow-growing painless mass without specific symptoms. Here we report an unusual case of a 55-year-old female with retroperitoneal FDCS who presented with progressive abdominal pain onset and acute exacerbation.

METHODS

On CTA, a middle-upper abdominal mass (58*40 mm) was shown with multiple enlarged lymph nodes. After en-bloc resection of the tumor, the patient recovered completely from her symptoms and was discharged without complication. One month later, the patient returned for follow-up and the relevant tests were completed.

RESULTS

In this case, CA724 elevated significantly and seemed to be associated with tumor progression. The results of positron emission tomography/computed tomography (PET/CT) and radiological examinations, including magnetic resonance imaging (MRI) and computed tomography angiography (CTA), were discussed to improve our understanding of diagnostic tools on FDCS. Targeted genomic sequencing analysis revealed three novel gene mutations, EPHA3 (nonsense mutation), DDR2 (SNV), and BIRC3 (InDel).

CONCLUSION

We reported an unusual case of retroperitoneal FDCS with acute exacerbated abdominal pain. The interpretations of CA724, PET/CT, as well as imaging results deserve further investigation in FDCS. Genomic sequencing revealed three novel gene mutations in FDCS, including EPHA3 (nonsense mutation), DDR2 (SNV), and BIRC3 (InDel).

Survival analysis in patients with follicular dendritic cell sarcoma: a population-based study

Follicular dendritic cell sarcoma (FDCS) is a rare low-intermediate grade malignant neoplasm. To date, published data on FDCS clinical courses are sparse, and no conditional survival study has been performed. Thus, we retrospectively analyzed 187 patients diagnosed with FDCS from the Surveillance, Epidemiology, and End Results (SEER) database. In this study, the median age at diagnosis was 50 years and 91 (48.7%) patients were male. The most common primary location was the abdomen/pelvis (82, 43.9%). The 1-year, 3-year, and 5-year overall survival (OS) were 88.7%, 69.0%, and 59.8%, respectively. The 5-year conditional overall survival increased from 65.7% at baseline to 83.8% in 5-year survivors. The 3-year FDCS-specific death rate was 26.7% and the rate of death from other reasons was 3.7%. In addition, the annual death hazard was the highest in the first four years after diagnosis and increased again in the 7th and 8th years. Age > 60 years at diagnosis, metastatic disease, and FDCS in thoracic organs were associated with shorter OS and FDCS-specific survival. In addition, FDCS patients, with either local or metastatic disease, could benefit from surgery therapy. In addition, adjuvant radiotherapy or chemotherapy for local disease provided no significant improvement in overall survival or FDCS-specific survival. We hope these findings may guide treatments and surveillance strategies for FDCS patients in clinical practice.

A Rare Case of Primary Follicular Dendritic Cell Sarcoma of the Kidney

The objective of this case report is to describe a rare case of primary follicular dendritic cell sarcoma (FDCS) of the kidney. FDCS is a rare soft tissue malignancy that most often presents intranodally with lymphadenopathy of the neck, mediastinum, and axilla. One-third of cases present extranodally and most commonly affect the liver, lung, and tonsils. To date, there have been few reports of retroperitoneal FDCS and, to the best of our knowledge, only two other reported cases with primary renal involvement. We present a 56-year-old female with end-stage renal disease on hemodialysis who presented to the hospital with a hypertensive emergency. Computed tomography (CT) of the abdomen was obtained revealing a left-sided renal mass and she subsequently underwent left radical nephrectomy. The pathologic features of the mass revealed oval to spindle cells with eosinophilic cytoplasm, dispersed vesicular chromatin, and small nucleoli found arranged in fascicles, whorls, and storiform patterns with occasional multinucleate forms. The neoplastic cells were immunoreactive to vimentin and expressed cell markers for CD23, CD35, and CD68. These features confirmed a final pathologic diagnosis of primary FDCS of the kidney. To our knowledge, this is the third case of primary renal FDCS reported in the literature. Extranodal FDCS is rare but does occur and needs to be on the differential diagnosis if pathologic features point to its diagnosis.

Favorable response to PD-1 inhibitor plus chemotherapy as first-line treatment for metastatic follicular dendritic cell sarcoma of the spleen: a case report

Follicular dendritic cell sarcoma (FDCS) is an uncommon low-grade malignant sarcoma. For localized FDCS, surgery is the most commonly recommended therapy option. However, there is no standard treatment protocol for metastatic FDCS. Here, we present a 68-year-old female with primary spleen FDCS who had multiple peritoneal metastases. She was treated with sintilimab (PD-1 inhibitor) plus chemotherapy (epirubicin plus ifosfamide) as first-line treatment achieving partial response (PR) and a relatively long progression-free survival (PFS) of 17 months. This case suggests that PD-1 inhibitor plus chemotherapy as first-line therapy seem to be a promising treatment option for metastatic FDCS.

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.

18 F-FDG PET/CT in Extensive Follicular Dendritic Cell Sarcoma With Response Assessment to Chemotherapy

ABSTRACT

Follicular dendritic cell sarcoma (FDCS) is a low-grade sarcoma of mesenchymal dendritic cell origin, and it constitutes <0.4% of soft tissue sarcomas. We report a rare case of FDCS in a 32-year-old man. 18 F-FDG PET/CT demonstrated the involvement of cervical, axillary, mediastinal, abdominal, and pelvic groups of lymph nodes and spleen. A cervical lymph node biopsy suggested FDCS. 18 F-FDG PET/CT scan done after 3 cycles of chemotherapy (CHOP regime) revealed a complete metabolic response. This case presents the rarity of extensive presentation and complete response to the CHOP regime.

Pancreatic follicular dendritic cell sarcoma: one case report and literature review

Pancreatic follicular dendritic cell sarcoma (FDCS) is a rare neoplasm with unclear pathological characteristics. In this study, we report one case of pancreatic FDCS and review published cases to summarize the characteristics and treatment of pancreatic FDCS. A man in his early 30 s was admitted for jaundice, abdominal fullness, and weight loss for 15 days. Computed tomography revealed a large capsule solid mass in the pancreatic head together with a dilated bile duct and enlarged retroperitoneal lymph nodes. Serum biochemistry revealed high total bilirubin levels (313.9 μmol/L) and normal tumor marker levels. Pancreatoduodenectomy was performed, but no chemotherapy was administrated at the patient's behest. The pathologic diagnosis was pancreatic FDCS infiltrating the duodenal seromuscular layer and common bile duct. The patient presented with liver metastasis 3 months after surgery and died 8 months after surgery from multiorgan failure. Pancreatic FDCS is a rare disease with high invasiveness. Our previous case exhibited paraneoplastic syndrome together with this disease, and further investigation is needed to confirm whether paraneoplastic syndrome is a typical syndrome of pancreatic FDCS.

Approche thérapeutique des maladies de Castleman : l’émergence des thérapies ciblées

The spectrum of Castleman disease encompasses several different disorders. Nowadays three different forms of the disease are individualized: unicentric Castleman disease, multicentric HHV-8 associated Castleman disease and idiopathic multicentric Castleman disease. In the latter a severe form called TAFRO syndrome (thrombocytopenia, anasarca, myelofibrosis, renal dysfunction, and organomegaly) tend to be individualized. Improvement in the classification and understanding of the physiopathology of CD have allowed improvement in treatment strategies. Treatment of rare but often severe manifestations, such as paraneoplastic pemphigus and bronchiolitis obliterans in unicentric CD and hemophagocytic syndrome and/or Kaposi' sarcoma in HHV8 associated CD, are better adapted. Most of current treatment strategies are based on retrospective and very few prospective studies. Both anti-IL6/6R and anti-CD20 biotherapies have greatly improved the management of certain forms of the disease. We report in this review the most relevant studies and national or international expert consensus statements for the treatment in the different types of CD. © 2022 Published by Elsevier Masson SAS on behalf of Société nationale française de médecine interne (SNFMI).

Follicular dendritic cell sarcoma of the spleen: A case report

Follicular dendritic cell sarcomas (FDCS) are spindle cell lesions that are large, slow-growing masses in either nodal or  extranodal regions or both and originate from B-cell follicles of the lymph nodes. Most tumors originate from the cervical lymph nodes, but retroperitoneal and mediastinal origins have also been reported. Extranodal areas include soft tissues, skin, tonsils, gastrointestinal tract, liver, and spleen. The spleen is an uncommon location for an FDCS and for this reason, the tumor may be underdiagnosed or overlooked because of confusion with other solid tumors. In this study, we present a patient with a splenic FDCS who presented clinically with abdominal pain and diarrhea. The patient underwent a splenectomy and had an uneventful remission.

Promising clinical outcome after body gamma knife radiotherapy for mediastinal follicular dendritic cell sarcoma with thoracic spine invasion and iliac metastasis: A case report and literature review

Background

Follicular dendritic cell sarcoma (FDCS) is a rare type of intermediate grade tumor. Mediastinal FDCS with spinal invasion has not been well described. The treatment options include surgical resection and radiation therapy. The body gamma knife is a stereotactic body radiotherapy (SBRT) technology that is widely used in China. The pathological evaluation of a bone lesion after a body gamma knife procedure has not been reported. Here, we report a case of a patient with FDCS with thoracic spine invasion and iliac metastasis treated with surgery and body gamma knife.

Case summary

A 36-year-old male patient was hospitalized at Zhongshan Hospital, Fudan University, due to a gradually aggravated pain on the lateral side of the left scapula for 6 months. Imaging examination showed neoplastic lesions on the left side of C7-T2 invading the vertebral body of T1, T2, and caput costae of the second rib and suspected metastasis in the left ilium. FDCS was diagnosed after performing a computed tomography (CT)-guided core needle biopsy, and the thoracic lesion was surgically resected. The body gamma knife was used as an adjuvant radiotherapy for the thoracic lesion and a primary therapy for the left ilium lesion. Iliac bone lesion resection was performed at Zhongshan Hospital, Fudan University, 10 weeks after RT. Compared with the biopsy report, the body gamma knife treatment resulted in a pathological complete response (PCR). The magnetic resonance imaging (MRI) examinations showed stable disease of the thoracic lesion after body gamma knife radiosurgery.

Conclusion

This case report describes the treatment of mediastinal FDCS with thoracic spinal invasion and iliac metastasis. The promising outcome suggests that separation surgery is an effective treatment option for mediastinal FDCS with spinal column invasion. It also demonstrates the application prospects of the body gamma knife treatment in malignant lesions of the axial bones.

Follicular Dendritic Cell Sarcoma in a Patient With Adolescent-Onset Crohn's Disease Exposed to Multiple Immunomodulator and Biologic Therapies

Children and adolescents with inflammatory bowel disease are often treated with immunomodulators (thiopurines, methotrexate) and biologics (anti-TNF, anti-integrin) for extended periods despite concerns about long-term safety. Here, we report a case of follicular dendritic cell sarcoma, a very rare malignancy, and the first reported presentation in a patient with inflammatory bowel disease exposed to infliximab, methotrexate, and vedolizumab. We review the key clinical features and diagnostic factors of this malignancy. The pathogenesis of follicular dendritic cell sarcoma is largely unknown, however, knock out of B-cell TNF in mice has been related to follicular dendritic cell dysregulation through its impact on NF-κB pathways and CXCL13 chemokines. It is unknown whether any relationship exists between this patient's diagnosis of Crohn's disease and therapeutic exposures to this rare malignancy. We document this case in the literature to raise awareness among other clinicians who may observe a similar case.

A rare case of follicular dendritic sarcoma of the vagina

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Follicular dendritic cell sarcoma of the vagina is a rare tumor.

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Follicular dendritic cell sarcoma has characteristic clinicopathologic findings.

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Awareness of follicular dendritic cell sarcoma can aide in diagnosis.

Follicular dendritic sarcoma of the vagina is an exceptionally rare malignancy. Here, we present a reproductive-aged female with no pertinent past medical history who initially presented with a protruding vaginal mass. Pathology from initial excision was consistent with follicular dendritic sarcoma of the vagina. This was ultimately treated with wide radical resection of the mass leading to iatrogenic vaginal stenosis.

Follicular dendritic cell sarcoma of the thigh: a clinicopathological report and management approach

Follicular dendritic cells are antigen-presenting immune accessory cells of mesenchymal origin. Follicular dendritic cell sarcomas (FDCS) typically occur in nodal and extranodal sites. However, presentation in the extremity has rarely been reported. A woman in her 60s had a painless, slow-growing right posterior thigh swelling, which had been present for 9 months. Imaging revealed a subcutaneous lesion in the posterior aspect of the right mid-thigh. Fine-needle aspiration cytology from the lesion was suggestive of a malignant spindle cell neoplasm, and she underwent its wide local excision. Immunohistochemistry showed expression of epithelial membrane antigen and CD35, but an absence of cytokeratin, desmin, CD23 and S100. The Ki-67 index was low and a diagnosis of FDCS was made. The lack of clinical guidelines was a challenge in the treatment of this rare case. A multidisciplinary board discussion played a critical role in the planning of the patient's adjuvant treatment.

Response of Tonsil Follicular Dendritic Cell Sarcoma to Multimodal Treatment Including Pembrolizumab: A Case Report and Literature Review

Follicular dendritic cell sarcoma (FDCS) is a rare malignant neoplasm that was classified by the World Health Organization (WHO) under histiocytic and dendritic cell neoplasms in the 2016 revision. Considering the rarity of this tumor, there is no standardized treatment. It is usually treated by complete surgical resection. Adjuvant chemotherapy and radiotherapy are alternative methods. Immune checkpoint inhibitors (ICIs) represented by the programmed death receptor 1/programmed death ligand 1 (PD-1/PD-L1) antibody have achieved significant clinical benefits in a variety of solid tumors. However, reports on the treatment of FDCS with ICIs are rare. FDCS often expresses high levels of PD-L1, which provides a rationale to use immunotherapy in cases of FDCS. Here, we present a 51-year-old Filipino-Chinese man with FDCS who was treated with multimodal treatment, including the PD-1 inhibitor pembrolizumab and achieved a relatively long disease-free survival of 24 months. This case emphasizes that the application of ICIs under the guidance of NGS technology seems to be a meaningful treatment option for patients with FDCS.

Follicular dendritic cells

Follicular dendritic cells (FDCs) are unique accessory immune cells that contribute to the regulation of humoral immunity. They are multitasker cells essential for the organization and maintenance of the lymphoid architecture, induction of germinal center reaction, production of B memory cells, and protection from autoimmune disorders. They perform their activities through both antigen-driven and chemical signaling to B cells. FDCs play a crucial role in the physiological regulation of the immune response. Dis-regulation of this immune response results when FDCs retain antigens for years. This provides a constant antigenic stimulation for B cells resulting in the development of immune disorders. Antigen trapped on FDCs is resistant to therapeutic intervention causing chronicity and recurrences. Beyond their physiological immunoregulatory functions, FDCs are involved in the pathogenesis of several immune-related disorders including HIV/AIDS, prion diseases, chronic inflammatory, and autoimmune disorders. FDCs have also been recently implicated in rare neoplasms of lymphoid and hematopoietic tissues. Understanding FDC biology is essential for better control of humoral immunity and opens the gate for therapeutic management of FDC-mediated immune disorders. Thus, the biology of FDCs has become a hot research area in the last couple of decades. In this review, we aim to provide a comprehensive overview of FDCs and their role in physiological and pathological conditions.

Nonlymphoid Hematopoietic Diseases Presenting in Bone, Soft Tissue, and Other Extranodal Sites

Context.—

Although rare in everyday practice, the initial presentation of hematopoietic neoplasms other than lymphoma in the musculoskeletal system and other extranodal sites can generate challenging diagnostic problems for surgical pathologists.

Objective.—

To review the morphologic and immunophenotypic features of various nonlymphoid hematopoietic diseases presenting at extranodal sites, with emphasis on the inherent diagnostic pitfalls and differential diagnoses of these entities to aid surgical pathologists in their accurate recognition.

Data Sources.—

Cases reviewed herein represent both in-house and consult cases seen at our institution between 2010 and 2021.

Conclusions.—

Entities that present in this way include myeloid neoplasms and histiocytic/dendritic cell neoplasms. These tumors commonly cause nonspecific symptoms, and their histologic appearance can overlap with a variety of benign neoplasms and reactive processes. This can lead to delay in diagnosis and intervention with potentially lifesaving therapy; thus, accurate and expedient recognition is of paramount importance.

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.

Concomitant malignancies in the neck: follicular dendritic cell sarcoma; a rare tumour presenting as a right-sided neck nodal mass and papillary carcinoma thyroid

Follicular dendritic cell sarcoma is a rare low-grade sarcoma of mesenchymal origin. It involves the lymph nodes more commonly and rarely extranodal sites. The most common lymph node is cervical and usually presents as a painless asymptomatic mass. More often, it is a misdiagnosis, and there is a delay in treatment. It is rarely associated with Castleman disease, myasthenia gravis. Diagnosis of this condition is by histopathology and immunochemistry. Surgery is the primary modality of treatment, and adjuvant therapy has been tried with no definite trials due to the rarity of the disease. Here, we report a case of concomitant follicular dendritic sarcoma of the right cervical lymph node and papillary carcinoma of the thyroid managed in our institute. There was a line of investigations approaching towards a diagnosis, and she underwent total thyroidectomy and right modified radical neck dissection.

Unexpected Favorable Outcome to PD-1 Antibody Plus Lenvatinib in a Patient With Recurrent Intestinal Follicular Dendritic Cell Sarcoma: A Case Report and Literature Review

Background

Follicular dendritic cell sarcoma (FDCS) is an uncommon malignant cancer, and there is no standard treatment to date. Resection followed by adjuvant chemotherapy or radiation is considered the most commonly used strategy for treatment. However, the treatment for patients who have progressed after systemic treatment is more controversial.

Case summary

In this case report, we describe a 57-year-old man with primary small intestine FDCS where surgery and second-line systemic chemotherapy failed. After disease progression (PD), the patient received sintilimab plus lenvatinib as third-line treatment and achieved a progression-free survival (PFS) with 7 months.

Conclusion

This is the first report of a FDCS patient treated with immune checkpoint inhibitors (ICIs) and antiangiogenic agents, sintilimab and lenvatinib, as third-line therapy. Our case provides a potential therapeutic option for patients with FDCS who progressed after multiline therapy.

Follicular dendritic cell sarcoma of the cervical lymph node diagnosed on fine needle aspiration cytology

Follicular dendritic cell sarcomas (FDCS) are rare tumours of lymph nodes and extranodal tissues which are grouped with the histiocytic and dendritic cell neoplasms. The diagnosis is usually made after thorough clinical and pathological examination with immunohistochemical analysis. Difficulties persist in diagnosing FDCS on cytological preparations. We report herein a case of a 57-year-old female who presented with a right neck mass of 5 months duration. Computed Tomography (CT) imaging of the neck reported a necrotic right level IIb lymph node and asymmetric fullness of the right palatine tonsil. Fine needle aspiration (FNA) biopsy revealed numerous spindle, oval and stellate neoplastic cells, arranged singly and in syncytia with moderate nuclear pleomorphism, vesicular chromatin pattern, and prominent nucleoli, sprinkled with small lymphocytes. The tumour cells were strongly diffusely positive for CD21, CD23, and D2-40 immunostaining on cell bock sections, but were negative for CD1a and CD34, supporting the diagnosis of FDCS. Follow-up surgical pathology on the resection showed histopathological features and an immunohistochemical profile consistent with FDCS.

Primary Follicular Dendritic Cell Sarcoma of Urinary Bladder

Follicular dendritic cell sarcoma is a rare malignant mesenchymal neoplasm composed of follicular dendritic cells. A subset of cases can be found at extranodal sites. Only 2 follicular dendritic cell sarcomas were previously reported in the urinary bladder. We report a follicular dendritic cell sarcoma that involved the urinary bladder of an 81-year-old woman, who presented with painless gross hematuria. The neoplasm was composed of large epithelioid cells with atypical nuclei, admixed with inflammatory cells. On immunohistochemistry, the neoplastic cells were reactive only for CD21, CD35, and vimentin. The tumor was considered unresectable due to its large size and proximity to the iliac vessels and the patient was treated with bortezomib, cyclophosphamide, and dexamethasone. Although a full course of chemotherapy was not completed due to adverse side effects, the tumor was reduced in size. A subsequent involved-field radiotherapy was performed. Three years postdiagnosis and 2 years after the radiotherapy treatment, a recurrent tumor was identified on imaging in the left posterolateral bladder wall. However, at that time the patient was found to have a newly developed advanced colonic adenocarcinoma. Three and a half months later she developed a bowel perforation and died.

Uncommon retroperitoneal tumour: follicular dendritic cell sarcoma

INTRODUCTION

Retroperitoneal Follicular Dendritic Cell Sarcomas represents rare tumours with aggressive biologic behaviour. Accurate diagnosis requires a combination of both morphological and immunohistochemical analyses.

PATIENTS AND METHODS

A 61-year-old man was referred to our Department with a left perinephric mass. Computed tomography scan showed a 5.5 cm circumscribed mass in front of the left renal vein abutting the first jejunal loop, with moderate heterogeneous contrast enhancement. Positron emission/computed tomography showed increased focal uptake in the lesion.

RESULTS

A retroperitoneal tumor located behind the first jejunal loop was found at laparotomy, encompassing the superior mesenteric vessels. Excision with en-bloc segmental small bowel resection was performed. Morphological and immunohistochemical analyses were consistent with Follicular Dendritic Cell Sarcoma.

CONCLUSIONS

Complete surgical resection in specialized multidisciplinary centers represents the treatment of choice for both primary or recurrent lesions since there is still no consensus on the role of adjuvant radio-chemotherapy.

International evidence-based consensus diagnostic and treatment guidelines for unicentric Castleman disease

Castleman disease (CD) includes a group of rare and heterogeneous disorders with characteristic lymph node histopathological abnormalities. CD can occur in a single lymph node station, which is referred to as unicentric CD (UCD). CD can also involve multicentric lymphadenopathy and inflammatory symptoms (multicentric CD [MCD]). MCD includes human herpesvirus-8 (HHV-8)-associated MCD, POEMS-associated MCD, and HHV-8-/idiopathic MCD (iMCD). The first-ever diagnostic and treatment guidelines were recently developed for iMCD by an international expert consortium convened by the Castleman Disease Collaborative Network (CDCN). The focus of this report is to establish similar guidelines for the management of UCD. To this purpose, an international working group of 42 experts from 10 countries was convened to establish consensus recommendations based on review of treatment in published cases of UCD, the CDCN ACCELERATE registry, and expert opinion. Complete surgical resection is often curative and is therefore the preferred first-line therapy, if possible. The management of unresectable UCD is more challenging. Existing evidence supports that asymptomatic unresectable UCD may be observed. The anti-interleukin-6 monoclonal antibody siltuximab should be considered for unresectable UCD patients with an inflammatory syndrome. Unresectable UCD that is symptomatic as a result of compression of vital neighboring structures may be rendered amenable to resection by medical therapy (eg, rituximab, steroids), radiotherapy, or embolization. Further research is needed in UCD patients with persisting constitutional symptoms despite complete excision and normal laboratory markers. We hope that these guidelines will improve outcomes in UCD and help treating physicians decide the best therapeutic approach for their patients.

Histiocytic and Dendritic Cell Sarcomas of Hematopoietic Origin Share Targetable Genomic Alterations Distinct from Follicular Dendritic Cell Sarcoma

Background

Histiocytic and dendritic cell neoplasms are a diverse group of tumors arising from monocytic or dendritic cell lineage. Whereas the genomic features for Langerhans cell histiocytosis and Erdheim‐Chester disease have been well described, other less common and often aggressive tumors in this broad category remain poorly characterized, and comparison studies across the World Health Organization diagnostic categories are lacking.

Methods

Tumor samples from a total of 102 patient cases within four major subtypes of malignant histiocytic and dendritic cell neoplasms, including 44 follicular dendritic cell sarcomas (FDCSs), 41 histiocytic sarcomas (HSs), 7 interdigitating dendritic cell sarcomas (IDCSs), and 10 Langerhans cell sarcomas (LCSs), underwent hybridization capture with analysis of up to 406 cancer‐related genes.

Results

Among the entire cohort of 102 patients, CDKN2A mutations were most frequent across subtypes and made up 32% of cases, followed by TP53 mutations (22%). Mitogen‐activated protein kinase (MAPK) pathway mutations were present and enriched among the malignant histiocytosis (M) group (HS, IDCS, and LCS) but absent in FDCS (72% vs. 0%; p < .0001). In contrast, NF‐κB pathway mutations were frequent in FDCSs but rare in M group histiocytoses (61% vs. 12%; p < .0001). Tumor mutational burden was significantly higher in M group histiocytoses as compared with FDCSs (median 4.0/Mb vs. 2.4/Mb; p = .012). We also describe a pediatric patient with recurrent secondary histiocytic sarcoma treated with targeted therapy and interrogated by molecular analysis to identify mechanisms of therapeutic resistance.

Conclusion

A total of 42 patient tumors (41%) harbored pathogenic mutations that were potentially targetable by approved and/or investigative therapies. Our findings highlight the potential value of molecular testing to enable precise tumor classification, identify candidate oncogenic drivers, and define personalized therapeutic options for patients with these aggressive tumors.

Implications for Practice

This study presents comprehensive genomic profiling results on 102 patient cases within four major subtypes of malignant histiocytic and dendritic cell neoplasms, including 44 follicular dendritic cell sarcomas (FDCSs), 41 histiocytic sarcomas (HSs), 7 interdigitating dendritic cell sarcomas (IDCSs), and 10 Langerhans cell sarcomas (LCSs). MAPK pathway mutations were present and enriched among the malignant histiocytosis (M) group (HS, IDCS, and LCS) but absent in FDCSs. In contrast, NF‐κB pathway mutations were frequent in FDCSs but rare in M group histiocytosis. A total of 42 patient tumors (41%) harbored pathogenic mutations that were potentially targetable by approved and/or investigative therapies.

Histiocytic and dendritic cell neoplasms are a diverse group of tumors arising from the monocytic or dendritic cell lineage. This article presents the molecular characteristics of the four major subtypes of malignant histiocytic and dendritic cell neoplasms, focusing on genomic alterations that could represent therapeutic targets.

Follicular dendritic cell sarcoma: Cytomorphologic features and diagnostic challenges

Follicular dendritic cell sarcoma (FDCS) is a rare malignant neoplasm, which primarily arises in lymph nodes with occasional cases occurring in extranodal locations. The diagnosis is often challenging particularly on cytology fine needle aspiration due to overlapping morphologic and immunohistochemical features. We present a case of FDCS diagnosed in an otherwise asymptomatic 33-year old male. The aim of our case report is to highlight the key cytomorphologic features and discuss various differential diagnoses of this unusual entity.

Follicular Dendritic Cell Sarcomas: CT and MRI Findings in 20 Patients

OBJECTIVE. The objective of this study was to assess the imaging features of follicular dendritic cell sarcoma (FDCS) on CT and MRI. MATERIALS AND METHODS. The clinical data and pretreatment findings of 20 patients with pathologically proven FDCS on CT (n = 15), MRI (n = 7), or both (n = 2) were analyzed retrospectively. Tumor location, number, size, morphology, attenuation or signal intensity, margin, presence of metastases, and contrast enhancement were evaluated. RESULTS. FDCS originated from lymph nodes (n = 6) or a variety of extranodal sites (n = 14). The tumors were typically solitary and well-circumscribed. Extranodal lesions (mostly in the abdomen or mediastinum with mean diameter, 11.8 cm) were larger than nodal lesions (mean diameter, 6.5 cm). Nodal-type cases presented with homogeneous masses on CT and MRI. However, on CT, all extranodal tumors (n = 12) showed heterogeneous attenuation, of which 91.7% (11/12) contained areas of lower attenuation because of internal necrosis and 50.0% (6/12) showed calcifications. On MRI, primary hepatic or splenic tumors (n = 3) also appeared as large heterogeneous masses. Seven patients (35.0%) had advanced-stage disease, and intraabdominal extranodal cases were more likely to have regional lymphadenopathy (n = 4) and distant metastases (n = 5). Hypervascularity was seen in 90.0% (18/20) of patients and progressive enhancement was seen in 11 (78.6%) of 14 tumors with multiphase imaging. CONCLUSION. FDCS is a rare, mostly solitary, well-delineated malignancy. A nodal-type FDCS typically presents as a small homogeneous mass, whereas an extranodal FDCS in the mediastinum or abdomen manifests as a large heterogeneous mass with internal necrosis and calcifications accompanied by regional lymphadenopathy. Hypervascularity and progressive enhancement can be seen in the majority of tumors.

Metastatic follicular dendritic cell sarcoma treated with gemcitabine plus docetaxel with an outstanding survival: A case report and review of literature

Follicular dendritic cell sarcoma responded dramatically to chemotherapy with gemcitabine and docetaxel.

Disease Response to Pazopanib in Follicular Dendritic Cell Sarcoma

Follicular dendritic cell sarcoma (FDCS) is a rare sarcoma, which commonly presents as a slow-growing, painless mass. There are only a few hundred reported FDCS cases, and the role for adjuvant chemo- or radiation therapy has not been established. Choosing an appropriate therapy in disseminated disease can therefore be challenging. A 26-year-old patient with FDCS was admitted with dyspnea, fever, and night sweats. He was found to have a large right hemothorax with compressive atelectasis on initial imaging. CT of the chest revealed multiple bilateral lung and pleural nodules with associated bilateral hilar adenopathy, a hypodense mass within the right hemithorax, and necrotic right external iliac and inguinal nodes. Inguinal node biopsy diagnosed FDCS. The patient was initially treated with cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy. Gemcitabine/Taxotere was given as second-line therapy and pembrolizumab as third-line therapy, with continued disease progression after 2 cycles of both regimens. The patient was switched to fourth-line therapy with pazopanib and had a partial response for 9 months. This case illustrates a successful FDCS treatment with pazopanib. Due to the rarity of FDCS, where large studies comparing treatment approaches are not available, recommendations for optimal treatment are not well defined. This case is in support of growing evidence suggesting that FDCS responds to systemic therapies that are used for soft tissue sarcoma, such as pazopanib.

Descriptive Analysis of Histiocytic and Dendritic Cell Neoplasms: A Single-Institution Experience

PURPOSE

Histiocytic and dendritic cell neoplasms are rare hematologic tumors. This study aimed to describe the epidemiologic features of the entire spectrum of histiocytic and dendritic cell neoplasms, including clinicopathological variables and patient outcomes.

MATERIALS AND METHODS

We comprehensively reviewed 274 patients who were diagnosed with histiocytic and dendritic neoplasms at Severance Hospital, Seoul, South Korea between 1995 and 2018.

RESULTS

The most common neoplasm was Langerhans cell histiocytosis (LCH), followed by dermal xanthogranuloma. Among non-LCH sarcomas, histiocytic sarcoma (HS) showed a relatively high prevalence, followed by follicular dendritic cell sarcoma (FDCS). Disseminated juvenile xanthogranuloma (DJG), Erdheim-Chester disease (ECD), indeterminate dendritic cell tumor (IDCT), and interdigitating dendritic cell sarcoma (IDCS) rarely occurred. Generally, these tumors presented in childhood, although the non-LCH sarcoma (HS/FDCS/IDCS/IDCT) group of tumors and ECD occurred in late adulthood. Multiorgan involvement and advanced Ann-Arbor stage, as well as recurrence and death of disease, were not uncommon. The non-LCH sarcoma group had the worst overall survival, compared to the DJG, ECD, and LCH groups.

CONCLUSION

Our findings indicate that histiocytic and dendritic cell neoplasms exhibit heterogeneous epidemiologic characteristics and that some patients may have unfavorable outcomes, especially those with non-LCH sarcoma.

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.

Imaging findings of inflammatory pseudotumor-like follicular dendritic cell tumors of the liver: Two case reports and literature review

BACKGROUND

Inflammatory pseudotumor-like follicular dendritic cell (IPT-like FDC) tumors of the liver is an uncommon tumor with extremely low incidence. To date, the radiologic findings of this tumor in multiphase computed tomography (CT) and magnetic resonance imaging (MRI) imaging have not been described.

CASE SUMMARY

Patient 1 is a 31-year-old Chinese female, whose complaining incidentally coincided with the finding of multiple liver masses. In the local hospital, an abdominal enhanced CT found two hypo-dense solid lesions, with heterogeneous sustained hypoenhancement, in the upper segment of the liver’s right posterior lobe. In our hospital, enhanced magnetic resonance imaging (MRI) with hepatocyte-specific contrast agents showed a similar enhanced pattern of lesions with patchy hyperintensity in the hepatobiliary phase (HBP). The patient underwent surgery and recovered well. The final pathology confirmed an IPT-like FDC tumor. No recurrence was found on the regular re-examination. Patient 2 is a 48-year-old Chinese male admitted to our hospital for a huge unexpected hepatic lesion. A dynamic enhanced abdominal CT revealed a huge heterogeneous enhanced solid tumor in the right lobe of the liver with a size of 100 mm × 80 mm, which showed a heterogeneous sustained hypoenhancement. In addition, enlarged lymph nodes were found in the hilum of the liver. This patient underwent a hepatic lobectomy and lymph node dissection. The final pathology confirmed an IPT-like FDC tumor. No recurrence was found upon regular re-examination.

CONCLUSION

When a hepatic tumor shows heterogeneous sustained hypoenhancement with a patchy enhancement during HBP, an IPT-like FDC tumor should be considered in the differential diagnosis.

Temozolomide targets and arrests a doxorubicin-resistant follicular dendritic-cell sarcoma patient-derived orthotopic xenograft mouse model

Follicular dendritic cell sarcoma (FDCS) is a very rare and highly recalcitrant disease. A patient's doxorubicin-resistant FDCS was previously established orthotopically on the right high thigh into the biceps femoris of mice to establish a patient-derived orthotopic xenograft (PDOX) model. The aim of the present manuscript was to identify an effective drug for this recalcitrant tumor. Here, we evaluated the efficacy of temozolomide (TMZ), trabectedin (TRAB) and pazopanib (PAZ) on the FDCS PDOX model. PDOX mouse models were randomized into five groups of eight to nine mice, respectively. Group 1, untreated control with PBS, i.p.; Group 2, treated with doxorubicin (DOX), 2.4 mg/kg, i.p., weekly for 3 weeks; Group 3, treated with PAZ, 50 mg/kg, oral gavage, daily for 3 weeks; Group 4, treated with TMZ, 25 mg/kg, oral gavage, daily for 3 weeks; Group 5, treated with TRAB, 0.15 mg/kg, i.v., weekly for 3 weeks. Body weight and tumor volume were assessed 2 times per week. TMZ arrested the FDCS PDOX model compared to the control group (p < 0.05). PAZ and TRAB did not have significant efficacy compared to the control group (p = 0.99, p = 0.69 respectively). The PDOX tumor was resistant to DOX (p= 0.99). as was the patient. The present study demonstrates that TMZ is effective for a PDOX model of FDCS established from a patient who failed DOX treatment, further demonstrating the power of PDOX to identify effective therapy including for tumors that failed first line therapy.

Primary hepatic follicular dendritic cell sarcoma: A case report

BACKGROUND

Follicular dendritic cell sarcoma (FDCS) is an uncommon type of tumor with low incidence. To date, no standard treatment for the disease has been established. Surgery remains the main treatment. Adjuvant chemotherapy and radiotherapy are optional approaches. Metastatic cases require multidisciplinary collaborative treatments. However, the choice of chemotherapeutic drugs is controversial.

CASE SUMMARY

A 66-year-old Chinese woman presented to our hospital complaining of intermittent pain of right upper quadrant. An enhanced computed tomography (CT) scan of the abdomen revealed hepatocellular carcinoma. Subsequently, the patient underwent a radical partial hepatectomy. Primary FDCS of the liver was diagnosed pathologically. Except for regular follow-up examinations, the patient did not receive adjuvant chemotherapy or radiotherapy. However, fluorine-18-fluorodeoxyglucose positron emission tomography/CT (PET/CT) confirmed lymph node metastases in the space of ligamentum hepatogastricum and pancreatic head, as well as the portacaval space. The patient was given systemic chemotherapy with gemcitabine and docetaxel for she was unsuitable for surgery. Satisfactorily, the metastatic lymph nodes were significantly reduced to clinical complete remission after eight cycles of chemotherapy. Then, strengthened radiotherapy was followed when the patient rejected the opportunity of surgery. Eventually, the carcinoma got better control and the patient was free of progression.

CONCLUSION

This case highlights the importance of making suitable chemotherapy regimens for the rare tumor. The combination of gemcitabine, docetaxel, and consolidated radiotherapy may offer a new promising option for the treatment of metastatic hepatic FDCS in the future.

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

RATIONALE

Follicular dendritic cell (FDC) sarcoma is a rare tumor with FDC differentiation that typically arises within lymph nodes but can also occur extranodally. To date, the primary esophageal FDC sarcoma has not been reported in the English literature.

PATIENT CONCERNS

We described a 67-year-old female who foremostly presented with dysphagia, and the patient was readmitted due to a dry cough and pain of his right shoulder 2 years after initial treatment.

DIAGNOSES

Primary esophageal FDC sarcoma with the right superior mediastinal lymph node metastasis.

INTERVENTIONS

The esophageal tumor was removed by endoscopic submucosal dissection at the first hospitalization. At the second hospitalization 2 years after the initial visit, the tracheal stent loaded with (125) iodine radioactive seeds was placed. The profiles of genetic variations and immunotherapeutic biomarkers were also explored by next-generation sequencing protocol from the patient's blood, esophageal primary, and mediastinal metastatic tumor samples.

OUTCOMES

The patient's symptom transitorily relieved, but she gave up further treatment and died 2 months after the tracheal stent was placed. As for the genomic alterations, we found 9 gene mutations in all the samples, including checkpoint kinase 2(CHEK2), FAT atypical cadherin 1 (FAT1), tumor protein 53 (TP53), DPYD, ERBB2 interacting protein (ERBB2IP), FBXW7, KMT2D, PPP2R1A, TSC2, whereas amplification of MYC was only in the metastatic example. The analysis of clonal evolution and phylogenetic tree showed the propagation and replay of polyclonal esophageal FDC sarcoma. At the same time, the detection of biomarkers for immunotherapy revealed microsatellite stable and mismatch repair-proficient (pMMR), which predicted a relatively poor anti-programmed death (PD-1)/programmed death ligand (PD-L1) immunotherapy outcome. On the contrary, the tumor mutational burdens were 10 mutations per 1 million bases in both the primary and metastatic tumor sample, which ranked the top 23.3% in solid tumors mutational burdens database of Geneseeq and might be a good predictor of the efficacy of anti-PD-1/PD-L1 immunotherapy.

LESSONS

To the best of our knowledge, this case report announced the first case of extranodal primary esophageal FDC sarcoma in the world, and firstly revealed its unique genetic alterations profiles, which might contribute to further in-depth study of this rare disease.

Unicentric Castleman disease presenting as a retroperitoneal peripancreatic mass: A report of two cases and review of literature

Castleman disease (CD) is a rare disorder of lymph nodes and related tissues. CD generally occurs in the mediastinum, as well as in cervical, retroperitoneal and axillary regions. The disease is classified into two major types: unicentric CD (UCD) and multicentric CD. The occurrence of UCD in the retroperitoneal peripancreatic region is quite rare. We encountered two cases of retroperitoneal peripancreatic UCD in our hospital during the past three years. Following a series of medical examinations, including magnetic resonance imaging, computed tomography, ultrasonography and postoperative histopathological examination, these two patients were diagnosed with UCD, which presented as a retroperitoneal peripancreatic mass. The mass in each patient was completely excised, and no postoperative radiochemotherapy was administered. Both patients recovered well without recurrence during a follow-up period of 30 mo and 8 mo.

Inflammatory Pseudotumor-Like Follicular Dendritic Cell Sarcoma of the Spleen: Computed Tomography Imaging Characteristics in 5 Patients

OBJECTIVES

The purpose of this study was to retrospectively review the computed tomography (CT) and clinicopathological characteristics of inflammatory pseudotumor (IPT)-like follicular dendritic cell sarcoma (FDCS) of the spleen in 5 patients.

METHODS

Clinical, pathologic, and CT imaging findings of 5 patients with IPT-like FDCS of the spleen were reviewed and analyzed. Computed tomography imaging and pathologic features were compared.

RESULTS

Abdominal unenhanced CT revealed a well-defined hypodense mass in the spleen with complex internal architecture with focal necrosis and/or speckle-strip calcification. On postcontrast CT, slightly delayed enhancement was observed in 5 cases. Four patients had a normalized spleen. The fourth patient had lung metastasis. The fifth patient had 2 relatively small lesions as well as metastases to the spine.

CONCLUSIONS

Computed tomography imaging features of IPT-like FDCS of the spleen are distinctly different from other hypovascular splenic neoplasm; however, the definitive diagnosis requires further confirmation with needle biopsy or surgery. Inflammatory pseudotumor-like FDCS of the spleen should be suggested by using the CT imaging features of the splenic mass with evidence of metastatic disease.

Follicular dendritic cell sarcoma of the porta hepatis

Follicular dendritic cell (FDC) sarcoma is a very rare neoplasm which commonly involves the lymph nodes and less commonly involves extranodal organs such as the liver. Most cases of FDC sarcoma are idiopathic, however some cases are associated with other disease states. Management of FDC sarcoma is primarily focused on surgical resection of the mass, and secondarily focused on radiotherapy, chemotherapy and/or biologic pharmacotherapy. We report the case of a patient who was found to have FDC sarcoma presenting as an obstructing mass of the porta hepatis, a manifestation which does not appear to be reported in the literature.

Epidemiology of Castleman Disease

Castleman disease is a rare entity, including unicentric Castleman disease (UCD), human herpesvirus-8 plus Castleman disease (HHV-8+MCD), and idiopathic multicentric Castleman disease (iMCD). UCD is the most common at 16 per million person years and occurs at every age. HHV-8+MCD incidence varies widely, mostly affecting human immunodeficiency virus-positive men. iMCD is likely a more heterogeneous disease with an estimated incidence of 5 per million person years. Improved definitions should improve understanding of the epidemiology of Castleman disease and its subtypes.

Prognostic factors for histiocytic and dendritic cell neoplasms

Histiocytic and dendritic cell neoplasms are rare and poorly studied. We report the clinical characteristics and prognostic factors in such cases in Japan. We investigated the clinical characteristics and survival in 87 adult patients with histiocytic and dendritic cell neoplasms. Fifty patients had histiocytic sarcoma, 12 had Langerhans cell histiocytosis, 11 had follicular dendritic cell sarcoma, 8 had Langerhans cell sarcoma, 6 had interdigitating cell sarcoma and 1 had indeterminate dendritic cell sarcoma. The median follow-up period was 18.0 (range: 9.6-71.8) months, and median overall survival (OS) was 23.5 months. The 2-year OS rate was 49.2%. In the multivariate analysis, elevated lactate dehydrogenase (LDH) (p =.004), ECOG performance status (PS) 2-4 (p =.006), and Ann Arbor stage III-IV (p =.008) affected OS. Stratification by elevated LDH, ECOG PS 2-4, and Ann Arbor stage III-IV allowed classification of patients into low risk, intermediate risk, and high risk groups. The same classification was applicable for HS and non-HS categories. In the rare neoplasms of histiocytic and dendritic cell sarcoma, ECOG PS, Ann Arbor stage, and LDH are important prognostic factors for predicting survival.