Follicular dendritic cell tumors of the oral cavity

Follicular dendritic cell sarcoma involving the parotid gland with expression of the melanocytic marker PRAME

Follicular dendritic cell sarcoma is a rare mesenchymal neoplasm arising from follicular dendritic cells (FDC) of lymphoid follicles. While the majority of FDC sarcoma cases arise within lymph nodes, approximately 30% manifest in extranodal sites. Only 4 prior occurrences of intra-parotid FDC sarcomas have been documented. We are reporting a rare case of FDC of the parotid gland in a 65-year-old male with a questionable history of B-cell lymphoma. The patient underwent a right total parotidectomy and bilateral neck dissection. A diagnosis of follicular dendritic cell (FDC) sarcoma was made, with one positive intra-parotid node. The malignant cells expressed the characteristic markers for FDC sarcoma but with positivity of the melanocytic marker PRAME. This is a case of FDC sarcoma with an unusual extranodal localization in the parotid gland. Immunohistochemistry was useful in making a diagnosis although the positivity for the melanocytic marker PRAME was unusual and unreported before.

Extranodal follicular dendritic cell sarcoma of the lung

Follicular dendritic cell sarcoma (FDCS) is a rare, mesenchymal neoplasm that may be nodal or extranodal in location. Lung involvement is rare. It is a slow-growing, painless tumor with a frequent capacity to recur and metastasize. We present a case of extranodal FDCS of the lung with an unusual presentation. A 34-year-old man presented with the complaints of haemoptysis and chest pain. A large left perihilar mass with endobronchial component was found on radiological evaluation. On endobronchial biopsy and mediastinal tru-cut biopsy, differential diagnoses of an inflammatory myo-fibrohistiocytic lesion and leiomyosarcoma were provided on the basis of morphological features of bipolar spindled cells arranged in intersecting fascicles and storiform patterns and immunophenotyping. A pneumonectomy was performed for the mass on which further immunohistochemical evaluation with CD21, CD35, and D2-40 finally helped form a diagnosis of FDCS. The patient recovered well from the surgery and has been on follow-up ever since. Owing to the rarity of this condition and its non-specific clinical features, FDCS is often misdiagnosed in the absence of appropriate immunohistochemistry. An of awareness of its morphological features and immunophenotype is, thus, necessary to provide early treatment and follow-up in order to prevent its recurrence and metastasis.

Primary follicular dendritic cell sarcoma of the kidney - a case report of a rare tumor with emphasis on diagnostic pitfalls

BACKGROUND

Follicular dendritic cell sarcoma (FDCS) is a rare low-grade tumor of the lymph nodes, but roughly one-third of the cases emerge from extranodal sites, posing diagnostic challenges.

CASE PRESENTATION

In this report, we present the case of a 59-year-old lady who complained of renal colic. During investigation, a kidney tumor was discovered. A radical nephrectomy was performed, and histological examination identified the tumor as a sarcomatoid renal cell carcinoma. The case was then referred to a genitourinary pathologist for further evaluation. The tumor cells exhibited positive staining for CD21, CD23, somatostatin receptor 2 A, and MDM2 expression. Additionally, MDM2 gene amplification was confirmed by the FISH study. Ultimately, the tumor was diagnosed as a primary renal FDCS. The patient was placed under active oncological surveillance and did not receive any further therapy. Remarkably, after 91 months of follow-up, she remains tumor-free.

CONCLUSION

This case represents a well-documented primary renal FDCS. Our aim in presenting this extremely rare tumor is to enhance awareness and highlight the importance of considering FDCS in the differential diagnosis.

Extranodal Follicular Dendritic Cell Sarcoma of the Head and Neck Region: A Clinicopathological Study of 7 Cases

Background. Follicular dendritic cell (FDC) sarcoma is a rare neoplasm arising from follicular dendritic cells (FDCs). It can be nodal or extranodal. Histological diagnosis of extranodal FDC sarcoma in the head and neck region is challenging and a significant percentage are misdiagnosed. Objectives. To report clinicopathological features of head and neck extranodal FDC sarcoma cases and discuss differential diagnoses. Methods. Seven head and neck extranodal FDC sarcomas were retrieved and clinicopathological features were noted. Results. Two tumors each involved parapharyngeal space and tonsil while remaining cases involved the parotid, soft tissue of neck and oropharynx. Age range was 12 to 79 years (mean and median age were 40 and 44 years respectively) and there was a male predilection (6 males: 1 female). All showed spindle to ovoid cells arranged in fascicles, whorls and/or storiform pattern. Mitoses ranged from 3 to 20/mm2. All tumors expressed CD21 and CD23. Two patients died of their disease at 9 and 16 months. Both had tumors larger than 5 cm with ≥10 mitoses/mm2. Three patients were alive at 12, 44 and 184 months. Conclusions. There was a distinct male predominance in our cohort. FDC sarcoma should be included in the differential diagnosis of spindle cell extranodal neoplasms in the head and neck with a whorled growth pattern and intratumoral lymphocytes. Head and neck region tumors show similar clinicopathologic characteristics as their counterparts at other locations with potential for aggressive behavior especially in tumors greater than 5 cm in size and with high mitotic rates.

Top Ten Lymphoproliferative Lesions Not to Miss When Evaluating Oral Ulcer Biopsies

BACKGROUND

Oral ulcers represent a full thickness loss of the mucosal epithelium leading to exposure of the submucosal connective tissue. These are common and usually self-limited lesions, although they may sometimes result from neoplasms, most commonly squamous cell carcinoma. Lymphoproliferative disorders may be difficult to diagnose in apthous ulcers since they mimic reactive inflammation.

METHODS

This review presents ten rare oral lymphoid proliferations which should not be missed when assessing oral ulcer biopsies.

RESULTS

The ten lesions include several with diagnostic cells which look similar to the histiocytes of a reactive inflammatory ulcer, including Rosai-Dorfman disease, reticulohistiocytoma, Langerhans cell histiocytosis, and traumatic ulcerative granuloma. Other lesions, such as EBV-positive mucocutaneous ulcer, extranodal marginal zone lymphoma of mucosal-associated lymphoid tissue, and plasmablastic lymphoma have lymphoid and/or plasma cell differentiation that mimic the reactive lymphocytes and plasma cells found in reactive ulcers. Two dendritic cell lesions, follicular dendritic cell sarcoma and blastic plasmacytoid dendritic cell neoplasm, both have distinct phenotypes which are required to make an accurate diagnosis.

CONCLUSION

Each of these lesions are diagnosed by evaluating their histology, along with their phenotypic profile, which is sometimes enhanced by pertinent molecular findings.

Follicular dendritic cell sarcoma of gastrointestinal tract with two emerging distinct subtypes: a case report and systemic review

BACKGROUND

Follicular dendritic cell sarcoma (FDCS) is a rare neoplasm of mesenchymal origin. FDCS of gastrointestinal tract (GI) are exceedingly uncommon.

CASE PRESENTATION

We report the first case of classic type FDCS in a 34-year-old male with Birt-Hogg-Dubé syndrome, which presented as a mass at the ileo-cecal junction. He received no further treatment after resection and remained disease free for 3.5 years. We further analyze and review the clinical and pathologic findings of 33 cases of GI tract FDCS reported in the literature.

CONCLUSIONS

There are two distinct subtypes of FDCS in the GI tract: the classic type occurs in relatively younger patients (mean = 45.3 years) without Epstein-Barr virus (EBV) association, and behaves more aggressively; the inflammatory subtype presents as colonic polypoid tumor in older patients (mean = 60.7 years) and is EBV positive. The clinical outcome in the latter group appears favorable although mortality rate is not necessarily low.

Epstein-Barr virus-positive inflammatory follicular dendritic cell sarcoma presenting as a solitary colonic mass: two rare cases and a literature review

AIMS

Follicular dendritic cell (FDC) sarcoma is a rare neoplasm originating from follicular dendritic cells in germinal centres. It is classified as conventional and Epstein-Barr virus (EBV)-positive inflammatory FDC sarcoma according to the 2019 World Health Organization classification of digestive system tumours; the latter is rarer. So in view of the rarity and difficulty in diagnosis, the aim of the manuscript is to share our experience of diagnosing EBV-positive inflammatory FDC sarcoma.

METHODS AND RESULTS

Here, we describe the clinicopathological features, gross description, histomorphology, immunophenotype, EBV-encoded mRNA (EBER) in-situ hybridisation, gene rearrangement and clinical follow-up of two patients with EBV-positive inflammatory FDC sarcoma in the colon, and review the relevant literature. The tumours were found in two males, aged 53 and 48 years, respectively, with a tumour diameter between 10 and 45 mm. Both cases occurred in the colon and presented as pedunculated colonic masses. Microscopically, scanty atypical ovoid to spindle neoplastic cells were mixed in a background of florid lymphoplasmacytic infiltration. The nuclei of these atypical cells showed vesicular chromatin and small, distinct nucleoli. Immunohistochemistry demonstrated that the atypical stromal cells were positive for CD21, CD23, CD35, and D2-40. EBER in-situ hybridisation also gave positive results in two cases. There was a mean follow-up of 9 months (range, 7-11 months).

CONCLUSION

EBV-positive inflammatory FDC sarcoma is an extremely rare tumour with a distinct morphology and phenotype. Therefore, it is very important to recognise it particularly for correct diagnosis and prevention of misdiagnosis and mistreatment.

Dedifferentiated Liposarcoma With Meningothelial-Like Whorls: Five Additional Cases and Review of the Literature

Background. Diagnosis of dedifferentiated liposarcoma (DDL) can sometimes be challenging due to a wide variety of histological features. "Meningothelial-like" whorl is an uncommon histological feature of DDL, which is also observed in neural tumors and follicular dendritic cell sarcoma. This feature is frequently associated with metaplastic bone formation. We conducted this study to describe the clinicopathological features of DDL with meningothelial-like whorls that would aid in establishing accurate diagnosis. Material and Methods. Microscopic glass slides of 5 cases of DDL with meningothelial-like whorls, diagnosed between January 2010 and December 2019, were reviewed. Results. Paratesticular region was the most common site. Whorls occupied 10% to 75% of tumor area and ranged in size from <0.1 cm to >2 cm. In 1 case, these whorls coalesced to form large areas of dedifferentiation. The cells forming whorls were spindle to epithelioid shaped and lacked significant nuclear pleomorphism and increased mitoses. Metaplastic bone formation was observed in 4 cases and cartilage formation in 3 cases. p16 and α-smooth muscle actin (α-SMA) immunohistochemical stains were positive in 2 cases, when performed. MDM2 gene amplification was observed in all cases by fluorescence in situ hybridization technique. These tumors showed aggressive behavior, similar to that of DDL without meningothelial-like whorls. Two patients died, 1 developed recurrence, 1 presented as recurrent tumor, and 1 developed metastasis. Conclusion. Meningothelial-like whorls in DDL most likely represent an early stage of dedifferentiation. Presence of well-differentiated liposarcoma areas, metaplastic bone formation, positive expressions for p16 and α-SMA immunohistochemical stains, and MDM2 gene amplification are useful diagnostic clues. These tumors have the potential to behave aggressively.

Fine-Needle Cytological Characteristics of Carcinoma Breast with Medullary or Medullary-like Features Masquerading as Dendritic Reticulum Cell Sarcoma: An Attempt to Explore the Reasons for Erroneous Cytologic Interpretation

Background:

Infiltration of tumors by dendritic reticulum cells (DRC) reflects the host immune defense mechanism. We observed three breast carcinomas cases with dense tumor-infiltrating DRC and lymphocytes in fine-needle aspiration (FNA) smears, leading to cytodiagnosis or differential diagnosis of dendritic reticulum cell sarcoma (DRCS). An attempt was made to find out the reason behind such an erroneous interpretation.

Materials and Methods:

Between 2009 and 2014, two cases were diagnosed as DRCS of the female breast by FNA cytology and in one case possibility of DRCS was considered along with medullary breast carcinoma (MBC). We compare and contrast the cytomorphological features of these three cases with those of nine cytologically diagnosed MBC.

Results:

Cases diagnosed as DRCS or MBC showed singly dispersed tumor cells, nuclear pleomorphism, bare nuclei, prominent nucleoli, and presence of lymphocytes. There was no significant difference between the two groups for discohesive clusters, syncytial clusters, plasma cells, neutrophils, foamy histiocytes, and necrosis. However, there was significant difference for presence of cohesive clusters (0% DRCS and 100% MBC, P = 0.00485), severe degree (+++) of pleomorphism (100% DRCS vs. 11.1% MBC, P = 0.01818), +++ DRC (P = 0.04697), and DRC with ++ to +++ enlarged nuclei (P = 0.03333), and pleomorphic nuclei (P = 0.00833). Two of the three cytologically diagnosed DRCS cases proved to be MBC or MBC-like and one as invasive ductal carcinoma. Six of nine cytologically diagnosed MBC cases with histology proved to be invasive breast carcinomas.

Conclusion:

Criteria for cytodiagnosis MBC need a fresh look. Cases with numerous dendritic cells possibly represent MBC.

Tonsillar p16-Positive Follicular Dendritic Cell Sarcoma Mimicking HPV-Related Oropharyngeal Squamous Cell Carcinoma: A Case Report and Review of Reported Cases

Follicular dendritic cell sarcoma (FDCS) is a rare entity which can share morphologic features with non-keratinizing squamous cell carcinoma. Recent reports suggest that up to half of FDCSs show immunohistochemical positivity for p16 (Zhang et al., in Hum Pathol 66:40-47, 2017), a stain that is conventionally used in the risk stratification of oropharyngeal squamous cell carcinoma (OPSCC). Herein, we report a case of p16-positive FDCS with clinical and histomorphologic overlap with human papilloma virus (HPV)-related OPSCC.

Primary Tonsillar Epithelioid Follicular Dendritic Cell Sarcoma: Report of a Rare Case Mimicking Undifferentiated Carcinoma and a Brief Review of the Literature

We present a 52 years old male with a left tonsillar follicular dendritic cell sarcoma with prominent epithelioid features that on light microscopical examination bore a striking resemblance to a lymphoepithelial or undifferentiated carcinoma. The tumor was immunohistochemically positive for CD21 and CD35 and negative for cytokeratins. Two distinct histopathological features (both present in our case) that may serve as clues to the correct diagnosis on light microscopical examination were formation of ectatic pseudovascular spaces lined by malignant cells and the presence of non-neoplastic multinucleated giant cells. Familiarity with the above-mentioned morphological clues, and awareness that this tumour may occur in anatomical sites outside the lymph node, are essential for accurate diagnosis.

Primary follicular dendritic cell sarcoma of the urinary bladder: the first case report and potential diagnostic pitfalls

BACKGROUND

Extranodal follicular dendritic cell sarcoma (FDCS) is a very rare malignancy with a variable clinical course. It is often not considered and has the potential to result in a misdiagnosis of other common sarcomas or sarcomatoid carcinomas. This is particularly true with the preoperative biopsy specimen, in which the tissue sample is often small.

CASE PRESENTATION

A case of FDCS in a 63-year-old woman, arising in the urinary bladder, a previously unreported site, is described. The patient presented with the typical clinical symptoms of a bladder cancer, and the morphology of the tumor was similar to a lymphoepithelioma-like carcinoma, ultimately resulting in it being misdiagnosed. The patient received radical cystectomy, without further radiotherapy or chemotherapy. Two years after operation, a metastatic tumor to the lung was found. The mass of the right main bronchus lumen was frozen and resected through bronchoscopy, and radiotherapy was performed. The patient has lived with the tumor since then.

CONCLUSIONS

This paper presents the first FDCS occurring in the urinary bladder with metastasis to the lung and emphasizes potential diagnostic pitfalls.

Clinicopathological Profile and Outcomes of Follicular Dendritic Cell Sarcoma of the Head and Neck Region - A Study of 10 Cases with Literature Review

INTRODUCTION

Follicular Dendritic Cell Sarcomas (FDCS) are rare disorders of the lymph node and soft tissues. Accurate characterization of these neoplasms is important in planning optimal treatment given its potential for recurrence and metastasis.

AIM

To analyse the clinicopathological profile and outcomes of a series of 10 cases of follicular dendritic cell sarcoma arising in the head and neck region diagnosed at our regional cancer centre.

MATERIALS AND METHODS

A series of 10 cases of FDCS of the head and neck region from the hospital registry of head and neck cancers diagnosed between 2007 and 2013 were collected and analysed retrospectively. Clinical details, pathologic features, immuno-phenotypic profile, treatment approach and outcomes over a period of 5 years were noted. The Recurrence Free Survivals (RFS) of all the patients were recorded.

RESULTS

The median age of the patients was 57 years and the mean age was 50.9 years. Male: female ratio was 7:3. In eight of the 10 patients, the tumours were located in the tonsils. All the tumour cells showed diffuse cytoplasmic CD21 and CD23 positivity by IHC. All the 10 cases underwent surgical excision of the tumour and three cases underwent additional neck dissection for cervical lymph node enlargement. All the patients with high grade tumours were uniformly managed with Tri-modality treatment (Surgery followed by radiotherapy and chemotherapy). The overall recurrence rate was 70%. The mean and median recurrence free survival was 39.6 and 44 months, respectively. Two of the three patients who remained recurrence free at the end of the 60 months had low grade tumours.

CONCLUSION

Early recognition of follicular dendritic cell sarcomas requires a high index of suspicion and bi-modality or tri-modality treatment may cure a subset of low and high grade tumours respectively and prolong recurrence in a large subset of patients. Surgery is the mainstay and the definitive modality of treatment; the advantages and benefit of adjuvant radiotherapy and chemotherapy are yet to be established. Tri-modality management may have a role in high grade patients which needs to be substantiated in future studies.

Follicular Dendritic Cell Tumor in Castleman's Disease

We report two cases of follicular dendritic cell tumor associated with Castleman's disease, one of the hyaline vascular type and one a mixed hyaline-vascular and plasma cell type. The reactive lymphoid follicles in both cases contained a proliferation of abnormal follicular dendritic cells characterized by enlarged, irregular contoured nuclei and prominent nucleoli (in-situ component). Both tumors had similar histology. They were vaguely fascicular and composed by eosinophilic, ovoid to spindled cells with vesicular nuclei and prominent nucleoli admixed with small lymphocytes. Some of these cells seen in the reactive follicles were similar in appearance to the ones seen in the adjacent invasive tumors. The association of follicular dendritic cell tumor with Castleman's disease and the presence of in-situ follicular dendritic cell tumor within reactive lymphoid follicles suggests that there may be a progression from dysplastic follicular dendritic cells to follicular dendritic cell tumor in Castleman's disease. The sequence of events and the likelihood that patients with Castleman's disease showing follicles with dysplastic changes will develop follicular dendritic cell tumors is not known at this time owing to the limited number of cases reported.

Paraneoplastic Pemphigus Associated with Follicular Dendritic Cell Tumor in the Mediastinum

Paraneoplastic Pemphigus (PNP) is an autoimmune bullous disease characterized by severe stomatitis, polymorphous skin eruptions, and underlying neoplasms. Diagnosis of cutaneous paraneoplastic disorders requires high index of suspicion. We describe a patient with PNP associated with follicular dendritic cell (FDC) tumor in the mediastinum, a rare neoplasm originating from follicular dendritic cells. Its management requires identification of underlying malignancy and treatment of the same. Our patient showed remission of PNP upon excision of the tumor and remained disease-free for 8 years.

Follicular dendritic cell sarcoma of the head and neck: Case report, literature review, and pooled analysis of 97 cases

BACKGROUND

Follicular dendritic cell sarcoma (FDCS) is a rare lymphoid neoplasm presenting in the head and neck. There are no pooled analyses of head and neck FDCS cases in the English language literature.

METHODS

A MEDLINE and PubMed review of cases from 1978 to February 2014 was performed. Demographics, clinicopathologic data, and outcomes were summarized.

RESULTS

We presented 2 patients and analyzed 97 cases. The mean age was 42.7 years (SD = 16.3 years). Outcomes were available for 76 patients. Tumors ≤4 cm had better disease-free survival (63% vs 28% at 5 years; p = .0282). Locoregional recurrence was significantly less likely with surgery and radiation compared to surgery alone (15% vs 45%; p = .019) and in patients receiving a neck dissection (10% vs 43%; p = .046).

CONCLUSION

This pooled analysis provides the largest sample size of FDCS of the head and neck to date and suggests that radiation and neck dissection may be beneficial to locoregional oncologic control. © 2015 Wiley Periodicals, Inc. Head Neck 38: E2241-E2249, 2016.

Follicular dendritic cell sarcoma of the right tonsil: A case report and literature review

The current study presents a case of extranodal follicular dendritic cell sarcoma (FDCS) of the tonsil and reviews the relevant literature. In the present case, a 59-year-old male presented with a globus sensation in the right pharynx for 6 weeks. On clinical examination, a painless non-ulcerated enlarged right tonsil was identified; the tonsil was covered with a normal mucus membrane. A right tonsillectomy was performed under general anesthesia. The final pathological diagnosis was follicular dendritic cell sarcoma of the right tonsil. Postoperatively, the patient received radiotherapy. The patient remains alive without disease recurrence or metastasis 44 months after tonsillectomy. To the best of our knowledge, only 42 cases of FDCS of the tonsil have been reported to date. Of the 42 cases, 41 patients underwent surgery and one patient refused treatment. A total of 23 (54.7%) received surgery alone. Adjuvant treatment was administered for 18 patients (42.9%). Six patients (14.3%) experienced local recurrences and two patients (4.8%) succumbed to the disease 24 months after treatment. The three-, five-, and eight-year overall survival rates for the entire group were 86.5, 77.8 and 77.8%, respectively. Furthermore, a tumor diameter of ≥4 cm was prognostic upon univariate analysis (χ²=4.634; P=0.031; excluding incomplete data). Tonsillar FDCS is rare and is associated with high rates of recurrence and metastasis, therefore, adjuvant treatment should be prescribed.

Extranodal follicular dendritic cell sarcoma: A clinicopathological report of four cases and a literature review

The aim of the present study was to characterize the clinicopathological features of follicular dendritic cell sarcoma (FDCS), and to report the experience of the Xin Hua Hospital Affiliated to Shanghai Jiaotong University School of Medicine (Shanghai, China) with this entity. The clinicopathological findings of four cases that had recently been encountered and 142 previously reported cases in the English literature were evaluated. The current tumors were found in two male and two female patients, aged 49–76 years old, who exhibited a mean tumor size of 8.7 cm. Three of the four cases were misdiagnosed during the initial diagnosis and one experienced intra-abdominal recurrence six months after the first diagnosis. Assessment of all 142 cases in the literature revealed a mild female predominance. The tumors exhibited a mean tumor size of ~7.0 cm. Histologically, the tumors were composed of plump spindle- or oval-shaped cells that exhibited eosinophilic cytoplasm and were arranged in sheets, storiform patterns or whorls. Immunohistochemically, the neoplastic cells expressed at least one of the FDC markers. Among the 130 cases with follow-up data, the overall recurrence, metastasis and mortality rates were 49.2% (64 cases), 21.5% (28 cases), and 13.8% (18 cases), respectively. FDCS can appear deceptively similar to other soft-tissue tumors, even poorly-differentiated carcinomas. A correct diagnosis requires a high degree of suspicion and immunohistochemical evaluation.

Extranodal Castleman disease of the extremities: a case report and review of the literature

Castleman disease is a rare lymphoproliferative disorder of unknown etiology that most commonly presents as a mediastinal nodal mass or, in the extranodal form of the disease, a mass located in the mediastinum or retroperitoneum. It is exceptionally uncommon for Castleman disease to present in the extremities. We report a rare case of extranodal Castleman disease presenting as a muscular forearm mass. We compare our case with the seven other reported cases in which Castleman disease presented as an isolated soft tissue mass in the extremities.

Follicular Dendritic Cell Sarcoma of the Inflammatory Pseudotumor-like Variant Presenting as a Colonic Polyp

Follicular dendritic cell (FDC) sarcoma is rare and is classified either as conventional type or inflammatory pseudotumor (IPT)-like variant. Extranodal presentation is uncommon and nearly all gastrointestinal FDC tumors are of the conventional type. IPT-like variant tumors occur almost exclusively in the liver and spleen and are consistently associated with Epstein-Barr virus (EBV). Here we report the case of a 78-year-old woman with an IPT-like FDC sarcoma presenting as a pedunculated colonic polyp. Histologically, scanty atypical ovoid to spindle cells were mixed with a background of florid lymphoplasmacytic infiltrate, which led to an initial misdiagnosis of pseudolymphoma. These atypical cells expressed CD21, CD23, CD35, and D2-40, and were positive for EBV by in situ hybridization, confirming the diagnosis. The patient was free of disease five months after polypectomy without adjuvant therapy. Although extremely rare, the differential diagnosis for colonic polyp should include FDC sarcoma to avoid an erroneous diagnosis. A review of the 24 cases of IPT-like FDC sarcoma reported in the literature reveal that this tumor occurs predominantly in females with a predilection for liver and spleen, and has a strong association with EBV.

Follicular dendritic cell sarcoma of parapharyngeal space: a case report and review of the literature

Follicular dendritic cell sarcoma (FDCS) of the parapharyngeal space is a rare malignant tumor. Only eleven cases of FDCS of the parapharyngeal space have been reported in English literature. Most of the reported cases developed tumor recurrence within 1 year or had metastasis. Because of the rarity of FDCS in the parapharyngeal space and peculiar histology, it can be misdiagnosed as undifferentiated carcinoma or meningioma. Therefore, pathologists should be aware of the existence of FDCS in this location. This paper aims to report a unique case of FDCS of the parapharyngeal space without recurrence in 26 months follow up with a review of the literature.

Follicular dendritic cell sarcoma of the tonsil

Follicular dendritic cells (FDCs) are non-phagocytic, non-lymphoid cells of immune system, which are necessary for antigen presentation and regulation of the reactions in the germinal centers of lymph node. Follicular dendritic cell sarcoma (FDCS) is unusual and those with an extranodal origin in the head and neck region are extremely rare. Here, we report a case of FDCS of the left tonsil in a 27-year-old male patient. The patient presented with swelling of the left tonsil and resultant difficulty in swallowing for last three months. The tumor was excised and was sent for histopathologic examination. Microscopic examination and immunohistochemical analysis proved the case to be FDCS. After the diagnosis, the patient received post-operative radiotherapy. The patient is on six months follow-up which is uneventful.

Dendritic cell sarcoma: a pooled analysis including 462 cases with presentation of our case series

Dendritic cell tumors are extremely rare and current knowledge on these tumors is limited. The characteristics of three dendritic cell sarcoma subtypes and their optimal treatment approaches are not fully clarified. We aimed to make a systematic review of the literature and enrich the current data with five new cases. Pooled analysis of 462 reported cases revealed that the tumor had no age, gender or racial predilection. Our analysis suggests that the young age, advanced stage, intraabdominal involvement and unfavorable histological features (i.e. large tumor size, absence of lymphoplasmacytic infiltration, coagulative necrosis, high mitotic count) may predict poor prognosis. Subtypes of this tumor have different clinical behaviors with interdigitating dendritic cell sarcoma being the most aggressive form. In general, surgery is the most effective treatment modality and adjuvant radiotherapy has no significant effect on overall survival of patients. The role of chemotherapy for the management of advanced disease is controversial.

Follicular dendritic cell sarcoma of the pharyngeal region

Follicular dendritic cell sarcoma (FDCS) is a rare neoplasm arising most commonly from follicular dendritic cells in the lymph nodes. It is exceedingly rare in extranodal sites, particularly in the pharyngeal region. The present study reports 3 cases occurring in the pharyngeal region. Case 1 had tonsil and cervical lymph node involvement, while case 3 also had tonsil involvement. Cases 1 and 3 relapsed locally at 3 and 17 months after surgery, respectively. Case 2 was diagnosed with a tumor in the parapharyngeal space and the patient succumbed to the disease 5 months after treatment with combined surgery and chemotherapy. All 3 cases were misdiagnosed initially. Pathological biopsy examination, including histopathology and immunohistochemistry, was essential for diagnosis. The data for 52 cases, including cases from the literature and the present cases, were analyzed. The results indicated that 57% (26/46) of the initial diagnoses were inaccurate, while the recurrence, metastasis and mortality rates were 40, 16 and 10%, respectively. The statistics supported the theory that FDCS of the pharyngeal region is a low-grade sarcoma. Involvement of the tonsils (52%, 27/52) and parapharyngeal space (19%, 10/52) were observed most commonly, while FDCS at various sites showed different prognoses. The various survival rates were calculated in the present study. The large tumors (≥4 cm) had a poorer prognosis than the small tumors (<4 cm; P<0.05). Among the 50 cases with available follow-up data, 46% (23/50) were treated with surgery alone, 52% (26/50) with combination therapy (surgery followed by chemotherapy and/or radiotherapy) and 2% (1/50) with surveillance. There was no statistically significant evidence (P>0.05) that combination therapy improves survival rates, compared with surgery alone.

Follicular dendritic cells: origin, function, and different disease-associated patterns

Follicular dendritic cells (FDCs) are a specialized type of antigen-presenting dendritic cells that are largely restricted to lymphoid follicles. They form dense three-dimensional meshwork patterns within benign follicles, which maintain the follicular architecture. The FDC function is to bind and retain antigens by linking to complement and immune complexes and then present these antigens to germinal center B cells that start the secondary immune response. FDCs aid in the rescue of bound B cells from apoptosis, and induce the differentiation of B cells into long-term memory B cell clones or plasma cells. We will discuss the different patterns of the FDC meshwork observed in different types of reactive and neoplastic disorders, which may be due to underlying different roles that FDCs may play in these disorders and whether changes in the architecture of the FDC meshwork can be useful in routine diagnostic practice or have a prognostic value.

The immunohistochemical profile of oral inflammatory myofibroblastic tumors

OBJECTIVE

The aim of this study was to demonstrate the immunohistochemical profile of oral inflammatory myofibroblastic tumors (IMTs) along with morphologic analysis.

STUDY DESIGN

Three cases diagnosed as oral IMTs were selected to compile an immunohistochemical panel constituted by calponin, caldesmon, Bcl-2, desmin, fibronectin, CD68, Ki-67, S100, anaplastic lymphoma kinase (ALK), α-smooth muscle actin, cytokeratins AE1/AE3, muscle-specific actin, CD34, and vimentin. An oral squamous cell carcinoma with a focal area of desmoplastic stroma was used as control for the stained myofibroblastic cells.

RESULTS

All oral IMTs were positive for calponin, revealing a strong and diffuse expression in the spindle-shaped cells. The lesions were also positive for vimentin (3/3), fibronectin (3/3), α-smooth muscle actin (3/3), and muscle-specific actin (1/3) and negative for h-caldesmon, Bcl-2, desmin, CD68, Ki-67, S100, ALK, cytokeratins AE1/AE3, and CD34.

CONCLUSIONS

Within the results encountered, the present panel should be of great assistance in the diagnosis of oral IMTs.

Extranodal follicular dendritic cell sarcoma in mesentery: A case report

Extranodal follicular dendritic cell (FDC) sarcomas are not a common phenomenon. Due to the scarcity of the identified cases reported in the literature, FDC is probably under-recognized and commonly misdiagnosed. The diagnosis of FDC sarcomas is based on node-based spindle cell lesions, and the expression of CD21, CD35 and clusterin. The most commonly involved extranodal sites include the oral cavity, tonsil, gastrointestinal tract and liver. With the aid of immunohistochemical analysis and the two most reliable FDC markers, CD21 and CD35, the diagnostic accuracy has improved. When FDC sarcoma is suspected histologically, immunohistochemical stains for FDC differentiation should be performed to avoid potential misdiagnosis. This case report concerns the evaluation of a 43-year-old male Chinese patient with a large extranodal FDC sarcoma (20×18×9 cm) in the mesentery with elevated serum CA125 (76.9 U/ml). The diagnosis and treatment of this disease are also discussed.

Follicular dendritic cell sarcoma of the tonsil

Follicular dendritic cell sarcoma (FDCS) is unusual, and those with an extranodal origin in the head and neck region are extremely rare. To date, no cases of tumors featuring the characteristics of follicular dendritic cells were reported in Korea. We report a new case of FDCS of the tonsils in a 65-year-old man. A diagnostic tonsillectomy was performed. Based on histopathologic and immunohistochemical findings, the patient was diagnosed with FDCS. Adjuvant radiotherapy was performed due to a high mitotic count. The patient survived with a 2-year disease free period. The differential diagnosis of a tonsillar mass must include FDCS. In cases in which FDCS is suspected on histopathologic examination, an immunohistochemical study is essential for the diagnosis.

Extranodal follicular dendritic cell sarcoma of the pharyngeal region: a potential diagnostic pitfall, with literature review

Extranodal follicular dendritic cell sarcoma (FDCS) of the pharyngeal region is a rare malignant tumor recognized in recent years, with approximately 37 cases so far reported in the literature. It is often not considered at the initial evaluation and may be misdiagnosed in a small biopsy specimen. We report 4 cases of extranodal FDCS, 2 cases in the nasopharynx that were diagnosed as undifferentiated carcinomas because they were characterized by syncytial epithelial cells with sheet or nest-like distribution and 2 cases in the tonsil and soft palate that were characterized by vaguely concentric whorls consisting of spindle to ovoid cells. The latter case was diagnosed as ectopic meningioma. The analysis of all cases from the literature and ours shows that 58% (21/36) of the cases are misdiagnosed initially, often as undifferentiated carcinoma or meningioma, which the differential diagnoses should be mostly focused on. With a median follow-up of 27 months, the recurrence, metastasis, and mortality rates are 23%, 21%, and 3%, respectively, suggesting that extranodal FDCS of the pharyngeal region remains a low-grade sarcoma. Radical surgery is recommended, whereas there is no evidence to support adjuvant therapy.

Extranodal follicular dendritic cell sarcoma

Extranodal follicular dendritic cell sarcoma is a rare tumor of follicular dendritic cells that can occur in a wide variety of sites. Although fairly well characterized histologically, with a distinct immunophenotype, it remains under-recognized, with as many as one third of cases initially misdiagnosed. This is often due to a failure to consider the entity. Patients with this tumor may have a worse prognosis than originally described. Prompted by a recent case at our institution, we briefly review the clinical features, etiology, histologic, and cytologic appearance of the tumor, as well as the ancillary studies useful in resolving diagnostic issues, primarily in an attempt to increase recognition of this rare neoplasm.

Dendritic cell neoplasms: an overview

Dendritic cell neoplasms are rare tumors that are being recognized with increasing frequency. They were previously classified as lymphomas, sarcomas, or histiocytic neoplasms. The World Health Organization (WHO) classifies dendritic cell neoplasms into five groups: Langerhans' cell histiocytosis, Langerhans' cell sarcoma, Interdigitating dendritic cell sarcoma/tumor, Follicular dendritic cell sarcoma/tumor, and Dendritic cell sarcoma, not specified otherwise (Jaffe, World Health Organization classification of tumors 2001; 273-289). Recently, Pileri et al. provided a comprehensive immunohistochemical classification of histiocytic and dendritic cell tumors (Pileri et al., Histopathology 2002;59:161-167). In this article, a concise overview regarding the pathological, clinical, and therapeutic aspects of follicular dendritic, interdigitating dendritic, and Langerhans' cell tumors is presented.

Dendritic cell sarcoma: an analytic overview of the literature and presentation of original five cases

Interdigitating and follicular dendritic cell sarcoma (DCS) are very rare diseases, with approximately 184 cases being reported thus far, and their best treatment modality is still on debate. This is a review of all the cases of dendritic cell sarcoma reported from 1981 until April 2006. This review is enriched with the original contribution of five cases occurred at our Institution from 1994 to 2006. The review of the literature pointed out that radical surgery alone was curative in approximately two thirds of these cases, the relapsing rate in patients who received adjuvant treatments being higher than 30%. We pinpoint new five cases of dendritic cell sarcoma (three FDCS and two IDCS). Both the analytic revision of the literature and our data suggest that localized DCS may be effectively treated by radical surgery and do not support the use of adjuvant treatments after radical excision.

Follicular Dendritic Cell Sarcoma of the Tonsil: A Case Report and Literature Review

We describe a case of follicular dendritic cell sarcoma (FDCS) of the tonsil in a 59-year-old woman. She was successfully treated with excision of the mass and postoperative radiation therapy. According to our review of the literature, only 25 cases of extranodal FDCS in the head and neck have been previously reported, including only 10 cases that involved a tonsil. We briefly review these earlier reports, and we discuss the diagnosis and management of FDCS.

[Extranodal follicular dendritic cell sarcoma of the tonsils]

Follicular dendritic cell (FDC) sarcoma is a rare tumor deriving from dendritic cells of the lymphoid follicle. Only a few cases of extranodal manifestation of FDC sarcoma of the head and neck have been reported. We describe the case of a 47-year-old woman with a FDC sarcoma of the left tonsil that first manifested 11 years ago. She has suffered three recurrences since this time, at continually reducing intervals. Histologically, the neoplasm consisted of an increased number of spindle-shaped cells with partly hyperchromatic nuclei. The patient underwent local tumor excisions, and then received an adjuvant chemotherapy with doxorubicin and ifosfamide when she presented with the third recurrence. The 11 year follow-up bears out a more aggressive behaviour of FDC sarcoma than first assumed. Therefore, a wide local excision, eventually combined with neck dissection in the case of recurrences, seems to be necessary.

Follicular dendritic cell sarcoma mimicking giant cell carcinoma of the pancreas

Extranodal follicular dendritic cell (FDC) tumors are rare. Recognition of the morphological spectrum of FDC tumors is important to clinical diagnosis. Herein is presented a case of pancreatic FDC sarcoma with unusual clinicopathological features. A 64-year-old male patient presented with weight loss, poor appetite, abdominal fullness, mild anemia and mild peripheral eosinophilia. Histologically, the tumor was composed of both epithelioid and spindle cells with abundant intracytoplasmic hyaline globules. These tumor cells were positive for CD21, CD23, CD35, S-100 protein, fascin and clusterin. Both epithelioid and spindle tumor cells independently colonized the liver and formed two tumor nodules 18 months after the initial resection. Notably, the two hepatic metastases additionally acquired patchy expression of human leukocyte antigen-DR. The epithelioid FDC in one of the hepatic lesions transformed into numerous bizarre giant cells, which could easily be confused with a metastatic giant cell carcinoma from the pancreas. FDC tumor should therefore be included in the differential diagnoses when dealing with a giant cell tumor.

Follicular dendritic cell sarcoma of the tonsil: case report

Follicular dendritic cell sarcomas are unusual, and extranodal origin is extremely rare. The English literature contains only eight cases in which this sarcoma has been presented as a tonsillar mass. We report a new case of follicular dendritic cell sarcoma of the tonsil in a 76 year old woman. The patient underwent diagnostic tonsillectomy for a left tonsillar mass, and follicular dendritic cell sarcoma was diagnosed based on histopathological and immunoperoxidase findings. Postoperative radiotherapy was performed. The patient is alive and disease-free at 4 years of follow-up. Without a high index of suspicion, this entity can easily be missed. We believe that follicular dendritic cell sarcoma should be included in the differential diagnosis for any tonsillar mass.

Extranodal follicular dendritic cell sarcoma: clinical, pathologic, and histogenetic characteristics of an underrecognized disease entity

It has been more than 10 years since follicular dendritic cell (FDC) sarcoma was first reported to occur in extranodal sites, yet extranodal FDC sarcoma still appears underrecognized, and its clinical and pathological characteristics remain to be defined. This study analyzed the clinical and pathological findings of three such cases that the authors encountered recently and 43 previously reported cases identified in the literature. Assessment of all 46 cases showed a slight female predominance (1.2:1) with a median age of 41.5 years. One-third of the cases were misdiagnosed at initial evaluation mainly because the possibility of FDC sarcoma was not considered. When considered, this disease had distinct pathological characteristics that allowed an accurate diagnosis. Staining for FDC markers, CD21, CD35, and clusterin was particularly helpful. The pathogenesis of the disease appeared heterogeneous, and associated factors included Epstein-Barr virus infection (in hepatic cases) and inflammatory pseudotumor-like conditions. Treatment modality varied widely although surgical resection was often included. With a median follow-up of 18 months, 43% of the cases recurred and 7% died of disease. The 5-year recurrence-free survival was 27.4%. From data available at the current time, we were not able to identify prognostically significant pathologic factors.

Follicular dendritic cell sarcoma of the tonsil: a case report

Follicular dendritic cell sarcomas of the tonsil are very rare tumors. Only 10 cases have been published in the English-language medical literature. We present an additional case that occurred in a 27-year-old woman. She presented with a tumor of the right tonsil. Histological sections of tonsillar biopsies and tonsillectomy suggested that this tumor was a nerve sheath tumor or a malignant melanoma. Histological examination and immunohistochemical study were reviewed. The final diagnosis was follicular dendritic cell sarcoma. She underwent a transoral resection of the right oropharynx with ipsilateral selective neck dissection and postoperative irradiation. We emphasize the difficulties in diagnosing this type of tumor. The use of monoclonal specific markers is required to avoid misdiagnosis. We discuss therapeutic methods for this rare tumor for which optimal treatment has not yet been defined.

Follicular dendritic cell tumor of the gastrointestinal tract: Report of a rare neoplasm and literature review

Follicular dendritic cell (FDC) tumor is a rare neoplasm of the accessory immune system showing FDC differentiation. Histologically, a conventional type and an inflammatory pseudotumor (IPT-like) type are recognized. The etiology of FDC tumor is unknown. While rare FDC tumors were associated with hyaline-vascular Castleman's disease (HVCD), hepatosplenic IPT-like FDC tumors consistently harbor EBV infection. FDC tumors of the gastrointestinal (GI) tract and mesentery/omentum are exceedingly rare, with only 17 cases reported so far. We report an additional case of an IPT-like FDC tumor of the ileum and mesentery in a 52-year-old schizophrenic man. The tumor consisted of highly atypical multinucleated giant cells in a background of intense lymphoid infiltrate with prominent eosinophilia reminiscent of Hodgkin's lymphoma. Tumor cells were immunoreactive for vimentin, CD21, CD35, fascin, smooth muscle actin and CD68, but were negative for all lineage-specific lymphoreticular, myeloid, mesenchymal and epithelial markers. Immunostaining for HHV-8 and in situ hybridization for EBV-encoded RNA (EBER) were negative. Some mesenteric lymph nodes showed HVCD-like changes. The differential diagnostic considerations of this unusual and rare neoplasm, mainly lymphocyte-rich GI stromal tumor (GIST), malignant lymphoma and inflammatory neoplasia of diverse histogenetic types, will be discussed together with a literature review on gastrointestinal FDC tumors.

Follicular dendritic cell sarcoma of the pharyngeal region: Histologic, cytologic, immunohistochemical, and ultrastructural study of three cases

Follicular dendritic cell sarcoma is a tumor of recent description and characterization; it is often underdiagnosed because it is easily confused with other entities. Three cases of follicular dendritic cell sarcoma are described in the present article. The first occurred in the parapharyngeal space in a 29-year-old woman who developed multiple recurrences over the span of 10 years. The second was located in the left tonsil in a 48-year-old man, and the third case developed in the parapharyngeal space in a 26-year-old man. All cases were positive for CD21 and CD35 and ultrastructurally they displayed a morphologic spectrum. The first case featured spindle cells with interdigitated long cell processes joined by well-developed desmosomes. In the other two cases there were round to ovoid cells with interwoven processes connected by occasional desmosomes. Including these three cases, a total of 20 follicular dendritic cell sarcoma of the pharyngeal region have been reported to date. The clinical behavior of these tumors is similar to other low-grade sarcomas.