HHV-8 is not associated with follicular dendritic cell tumours

Follicular Dendritic Cell Sarcoma

Follicular dendritic cell sarcoma is an uncommon neoplastic proliferation of spindled to ovoid cells with morphologic and immunophenotypic features similar to normal follicular dendritic cells. While most follicular dendritic cell sarcomas arise from lymph nodes, at least one-third occur in extranodal sites. A broad differential diagnosis can be developed--as this tumor has morphologic features similar to other tumors, hence creating a diagnostic pitfall--but its immunophenotypic profile is quite specific and is diagnostically crucial. Herein, we review the pathogenesis; histologic morphology; and immunohistochemical, electron microscopy, and clinical features, including treatment and prognosis, of follicular dendritic cell sarcomas. We will briefly describe the role of molecular studies including utility of BRAF mutations in diagnosing this tumor.

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.

Pediatric follicular dendritic cell sarcoma of the head and neck: a case report and review of the literature

OBJECTIVE

Follicular dendritic cell sarcoma is a rare disease with a non-specific and insidious presentation that is further complicated by difficult diagnostic and therapeutic assessment.

METHODS

The database PubMed was searched for reports of follicular dendritic cell sarcoma between 1986 (first case published) and 2012. All of the articles presenting informations regarding one or more cases of follicular dendritic cell sarcoma of the head and neck region, in patients less than 18 years of age, were included. The reference lists for pertinent reports were also scanned to ensure that all relevant literature was included.

RESULTS

We present a case of a 14 year-old girl, with a 2-month history of a right-sided level II neck mass. After a carefull radiologic evaluation the mass was resected combined with a right selective neck dissection. Histology with immunohistochemical staining was positive for follicular dendritic cell sarcoma. No recurrence was seen after 31 months follow-up. The literature search identified six more cases of pediatric follicular dendritic cell sarcoma of the head and neck. This is the first female patient with follicular dendritic cell sarcoma in the pediatric population.

CONCLUSIONS

Current treatment of head and neck follicular dendritic cell sarcoma consists of wide radical resection, with associated radiotherapy or chemotherapy only for cases with aggressive disease such as extracapsular invasion, tumor size ≥6 cm or after failure of the first-line surgical treatment.

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.

FDG-PET imaging in the diagnosis of HIV-associated multicentric Castleman disease: something is still missing

Now that [18F] fluorodeoxyglucose positron emission tomography (FDG-PET) has become an established imaging tool in oncology, it is attracting interest in the field of infectious diseases. Several studies have used FDG-PET to examine the pathophysiology of HIV infection as well as other conditions such as lipodystrophic syndrome and HIV-related neurocognitive disorders. In clinical practice, FDG-PET has been proposed to assess fever of unknown origin or with lymphoproliferative disorders such as Castleman disease in individuals with HIV infection.

Castleman's disease--a two compartment model of HHV8 infection

Castleman's disease is a primary infectious disease of the lymph node that causes local symptoms or a systemic inflammatory syndrome. Histopathology reveals a destroyed lymph node architecture that can range from hyaline-vascular disease to plasma-cell disease. Viral interleukin 6 (vIL-6) produced during the replication of human herpesvirus type 8 (HHV8) is the key driver of systemic inflammation and cellular proliferation. Stage progression of Castleman's disease results from switches between viral latency and lytic replication, and lymphatic and hematogenous spread. Multicentric plasma-cell disease in HIV-1 patients is associated with HHV8 infection. Polyclonal plasmablast proliferation escapes control in the germinal center with eventual malignant transformation into non-Hodgkin lymphoma. Surgery produces excellent results in unicentric disease, while multicentric disease responds to anti-CD20 therapy or IL-6 and chemotherapy. Lymphovascular endothelium and naive B cells are infectious reservoir-opening options for antiangiogenic and anti-CD19 strategies to enhance outcomes in patients with systemic disease.

Castleman disease: an update on classification and the spectrum of associated lesions

Since its initial description, researchers have expanded the spectrum of Castleman disease to include not only the classic and well-recognized hyaline-vascular type, but also the plasma cell type and multicentric types of broader histologic range, including human herpes virus-8-associated Castleman disease. These less common subtypes of Castleman disease are less familiar, and may be under-recognized. Also of practical importance, current authors are restructuring the classification of multicentric Castleman disease to accommodate the emerging pathogenic role of human herpes virus-8 and its association with the recently described plasmablastic variant. In addition to an increased risk of lymphoma, patients with Castleman disease also are at increased risk for other related neoplasms, including Kaposi sarcoma and follicular dendritic cell tumors, which are of prognostic and therapeutic relevance. This review focuses on the histologic diagnosis of Castleman disease, current and emerging concepts in its pathogenesis and classification, and associated histopathologic entities.

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 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.

Kaposi's sarcoma-associated herpesvirus: clinical, diagnostic, and epidemiological aspects

Kaposi's sarcoma-associated herpesvirus (KSHI) is one of the few viruses proven to be associated with tumorigenesis in humans. Its causal association with all clinical and epidemiological variants of Kaposi's sarcoma (KS) is well established. KSHV is also involved in the pathogenesis of primary effusion lymphoma (PEL) and a subset of multicentric Castleman's disease (MCD). Possible associations of KSHV with other clinical settings have been extensively examined. The findings from several of these studies are contradictory and are yet to be resolved. Concentrated effort over the last decade, since the initial discovery of KSHV, led to the development of several experimental systems that resulted in a better comprehension of the biological characteristics of KSHV and set the stage for the understanding of mechainisms by which diseases are induced by the virus. The development of molecular, histological, and serological tools for KSHV diagnosis allowed researchers to track the transmission and to study the epidemiology of KSHV. These assays have been applied, in particular in ambiguous cases, in order to confirm clinically and pathologically based diagnoses. Here, we review the advances in the clinical, experimental, diagnostic, and epidemiological research of KSHV.

[Recurrent Castleman's disease of the neck occurring in an infant]

INTRODUCTION

Castleman's disease is a lympho-proliferative disease of unknown cause. This rare disease, usually localized, is benign and develops in the young adult. The predominant localization is mediastinal.

OBSERVATION

A 15 month-old infant was referred for a left latero-cervical mass that had developed since the age of 3 months. Other than this, the clinical examination was normal. Sonography, x-ray and tomodensitometry confirmed the unique nature of the lesion and the absence of loco-regional invasion. Histology following surgical exeresis found a nodule with multiple pseudo-follicular structures. These mitosis-rich structures were arranged concentrically around a vessel and were bordered by small lymphocytes forming a crown. This histological aspect corresponded to Castleman's disease in its vascular hyaline form. Local recurrence was reported twice, 2 and 8 years later and was treated each time with surgical exeresis. Histological examination was always similar to the first.

DISCUSSION

Castleman's disease has rarely been reported in infants. The cervical location, at whatever age, is far rarer than the mediastinal form. Supplementary examinations are not always of interest and basically provide information on the isolated or multicentric nature. Surgical exeresis was justified because of the diagnostic doubts and the risk of compression. Diagnosis is based on anatomopathology. Relapses have rarely been described in the literature and raise the question of the potential malignant transformation after several relapses.

Interdigitating dendritic cell sarcoma of salivary gland associated lymphoid tissue not associated with HHV-8 or EBV infection

Interdigitating dendritic cell sarcoma (IDCS) is an extremely rare malignancy derived from professional antigen presenting cells. This report describes a case of IDCS arising in the salivary gland associated lymphoid tissue of the parotid gland of a 51 year woman, presenting with a painless neck swelling. Histologically, sheets of S100(+)/Ccd68(+)/CD45(+)/CD34(-)/CD1a(-) spindle cells were surrounded with an inflammatory infiltrate with no evidence of B or T cell clonal proliferations. No evidence of either human herpesvirus 8 or Epstein-Barr virus could be detected by quantitative polymerase chain reaction in the tumour cells with serological evidence of previous Epstein-Barr virus infection. The patient remains well and disease free 24 months after presentation without specific treatment.

Kaposi's sarcoma and other manifestations of human herpesvirus 8

Kaposi's sarcoma (KS) was described by Moritz Kaposi in 1872 and was known for an entire century as a rare disorder of older men usually of Eastern European, Mediterranean, and/or Jewish origin. In the early 1980s, the prevalence of KS began to increase dramatically and soon became the most common malignancy in patients with AIDS, especially those who were male homosexuals. In 1994, a new human herpesvirus (HHV) was found to be present in almost 100% of KS lesions. This virus was found to be a gammaherpesvirus, closely related to Epstein-Barr virus, and was designated HHV-8. Subsequently, HHV-8 DNA was found in almost all specimens of classic KS, endemic KS, and iatrogenic KS, as well as epidemic KS (ie, AIDS KS). It is now believed that HHV-8 is necessary, but not sufficient, to cause KS and that other factors such as immunosuppression play a major role. The use of highly active antiretroviral therapy (HAART) since 1996 has markedly reduced the prevalence of AIDS KS in western countries, but because 99% of the 40 million patients with AIDS in the world cannot afford HAART, KS is still a very common problem. Primary effusion lymphoma and multicentric Castleman's disease are also thought to be due to HHV-8. Although HHV-8 DNA has been described in a number of other cutaneous disorders, there is little evidence that HHV-8 is of etiologic significance in these diseases. The mechanism by which HHV-8 causes KS, primary effusion lymphoma, and multicentric Castleman's disease is not well understood but is thought to involve a number of molecular events, the study of which should further our understanding of viral oncology. (J Am Acad Dermatol 2002;47:641-55.)

LEARNING OBJECTIVE

At the completion of this learning activity, participants should be familiar with Kaposi's sarcoma and other manifestations of human herpesvirus 8.

Mediastinal mixed dendritic cell sarcoma with hybrid features

This report describes a recurrent sarcoma involving the soft tissues of the posterior mediastinum with features of both follicular dendritic and interdigitating dendritic cells. Histologically, the tumour, which was a recurrent neoplasm 19 years after the initial removal, was composed of bland spindle shaped cells with interspersed inflammatory cells, predominantly lymphocytes. Immunohistochemically, the spindle cells were positive for S100 protein, CD45, CD68, and vimentin, but negative for CD21 and CD35 (markers of follicular dendritic cells). The immunophenotype was in keeping with interdigitating dendritic cells. However, ultrastructural examination demonstrated elongated cell processes joined by desmosome-like junctions-features in keeping with follicular dendritic cells. Follicular dendritic cell sarcoma and interdigitating dendritic cell sarcoma are rare neoplasms and a high index of suspicion is required to make a correct diagnosis. Immunohistochemistry and/or electron microscopy are required for a definitive diagnosis. This case shows that hybrid neoplasms can occur, which have features of both follicular and interdigitating dendritic cells.