CT features of inflammatory pseudotumor like follicular dendritic cell sarcoma of the spleen / 中华肝胆外科杂志

Objective:To explore the CT features of inflammatory pseudotumor like follicular dendritic cell sarcoma (FDCS) of the spleen.Methods:The clinical data of 12 patients with splenic inflammatory pseudotumor like FDCS admitted to 3 central hospitals including Yongjia People's Hospital in Zhejiang Province from January 2015 to December 2022 were retrospectively analyzed, including 4 males and 8 females, with a median age of 60 years old. The number, shape, size and CT features of the lesions were analyzed based on patient's CT image data.Results:CT scans of 12 patients showed 15 lesions, including 10 single lesions and 2 multiple lesions. The lesions were circular in 5 cases, elliptical in 4 cases, and irregular in 3 cases. The median maximum diameter of the mass is 6.5 cm. On plain scan, all 12 tumors showed low density or slightly low density. The CT value is (41.3±7.2) HU; 8 cases had uneven density and 4 cases had uniform density. There were 8 cases with clear tumor boundaries and 4 cases with unclear boundaries. There were 8 cases with tumor necrosis and cystic transformation, and 5 cases showed patchy bleeding lesions in the center of the tumor. Enhancement: the arterial phase shows small patches or flocculent enhancement at the edges or parenchymal parts of the tumor, with CT value of (56.0±3.8) HU. Among them, there were 7 cases of mild enhancement, 4 cases of moderate enhancement, and 1 case of significant enhancement. During the portal phase, there was mild to moderate persistent small patchy uneven enhancement, with CT value of (62.0±4.3) HU. Among them, there were 8 cases of mild enhancement and 4 cases of moderate enhancement. The delayed phase showed a slow withdrawal of enhancement, with CT value of (45.0±8.2) HU. All 12 cases underwent complete resection and were diagnosed with FDCS through pathological examination.Conclusion:FDCS plain scan shows circular or elliptical uneven low-density masses, with small patches or flocculent light to moderate uneven enhancement in the arterial phase, continuous enhancement in the portal phase, and slow withdrawal in the delayed phase as the main characteristics.

Histopathological and immunohistochemical clues to the illusive diagnosis of follicular dendritic cell sarcoma: A clinicopathological masquerader

Follicular dendritic cell sarcoma is a rare histiocytic and dendritic neoplasm mainly involving the lymph nodes and selective extranodal sites. They are often misdiagnosed due to nonspecific clinical, radiological, and morphological findings in addition to their rarity. Four cases described below had variable age of presentation, site of involvement, size of the lesion, and histopathological features. Application of an extensive immunohistochemical panel, including a combination of >1 dendritic cell marker, clinched the diagnosis. A combination of D2-40 and Cluster of differentiation 21 (CD21) worked best in establishing a definite role in the current series. Programmed death-ligand 1 (PD-L1) analysis was positive in two of the three cases where it could be performed. However, none of our cases had received immunotherapy. Prompt recognition of the described histopathology features and incorporation of novel immunohistochemical markers can translate to timely initiation of therapy for this aggressive disease

Clinicopathological Features of Follicular Dendritic Cell Sarcoma / 中国医学科学院学报

To explore the clinicopathological and immunohistochemical characteristics of follicular dendritic cell sarcoma(FDCS)and the expressions of IgG and IgG4. We retrospectively analyzed the clinicopathological and immunohistochemical data of 9 pathologically confirmed FDCS cases in Peking Union Medical College Hospital from January 2005 to December 2018.Immunohistochemical staining of IgG and IgG4 were performed,and Epstein-Barr virus(EBV)-encoded RNA(EBER)in situ hybridization were carried out. Nine cases of FDCS included 4 men and 5 women aged 16-53 years [mean(38.2±9.7)years].The clinical manifestations included masses,lymph node enlargement,rash,and fever.The tumors were located in lymph node,retroperitoneal region,adrenal gland,neck,axillary region,and liver,respectively.Ultrasound showed clear boundary cystic or solid mass with maximum diameters of 1.5-15.0 cm.Microscopically,the spindle tumor cells were arranged in solid and storiform patterns with abundant and slightly stained cytoplasm,vacuolated nuclei,and small nucleoli.The mitosis was 1-3/10 high power fields,and necrosis was found in 5 cases.Immunohistochemically,the tumor cells were positive for CD21(6/9),CD35(6/9),and CD23(7/9). FDCS is a rare malignant tumor,which is easy to be missed.The combination of CD21,CD35,and CD23 is helpful for diagnosis.Hyaline-vascular type Castleman's disease may be the precursor of FDCS,and there may be only a small number of IgG4-positive plasma cells in FDCS.Surgical resection remains the main treatment for FDCS.

Follicular dendritic cell sarcoma aggravated by hyaline-vascular Castleman's disease in association with paraneoplastic pemphigus: study of the tumor and successful treatment

Abstract The authors have successfully treated and monitored a case of paraneoplastic pemphigus in association with follicular dendritic cell sarcoma aggravated by hyaline-vascular Castleman's disease. The patient was a 56-year-old female who presented with recalcitrant erosive lichen planus of the oral cavity, tongue, and genital mucosa, along with polymorphous eruptions throughout her body. Histological examination of the cutaneous lesions, indirect immunofluorescence on rat bladder epithelium, and western blot of human keratinocyte proteins identified anti-epidermal antibodies in the patient's serum. Positron emission tomography and computed tomography scans found a mass in her retroperitoneal region. Pathology and immunohistochemistry investigation further corroborated the diagnosis of follicular dendritic cell sarcoma originated from hyaline-vascular Castleman's disease. Complete remission was achieved and the patient has been monitored for four years.

Clinicopathological characteristics and differential diagnosis of interdigitating dendritic cell sarcoma / 中华肿瘤杂志

Objective@#To analyze the clinicopathological features and differential diagnosis of interdigitating dendritic cell sarcoma (IDCS).@*Methods@#The clinical pathological features of 7 IDCS were analyzed. Among them, the follow-up results of 6 cases were available.@*Results@#Among the 7 IDCS patients, 4 cases were male and 3 were female. The age of the patients ranged from 26 to 69 years.Three cases were originated from lymph nodes and 4 cases were originated from skin, stomach, adrenal gland and mesentery, respectively. Microscopically, the tumor cells presented as fascicular and storiform proliferation and infiltrated by lymphocytes. The tumor cells were short-spindle or ovoid, with indistinct border of cytoplasm. The immunohistochemistry results showed that tumor cells were S-100, Vim, CD68 and CD163 positive, and AE1/AE3, EMA, CD117, CD34, Desmin, SMA, CD1α, CD21, CD23, CD35, HMB45, Melan-A, MelanPan and ALK negative.The BRAF mutation and clonal rearrangement of T and B cells were not detected. Among the follow-up period of 7 IDCS patients, 3 occurred disease progressions.@*Conclusions@#IDCS is extremely rare with unique pathological features, and its lesion is not limited to the lymph node. The IDCS patients with extensive lesions may have worse prognose. The differential diagnosis of IDCS includes other histiocytic and dendritic cell neoplasms, malignant melanoma and soft tissue neoplasms.

Clinical pathologic characteristics of extranodal follicular dendritic cell sarcoma / 中华肿瘤杂志

Objective@#To investigate the clinical pathologic characteristics of extranodal follicular dendritic cell sarcoma (FDCS).@*Methods@#We collected 7 cases of extranodal FDCS, HE staining, immunohistochemical study were performed. The V600E mutation of BRAF in 7 cases were detected by real-time PCR and EBER in situ hybridization was performed on 4 cases.@*Results@#Among the 7 cases of FDCS, 5 cases were male and 2 cases were female, the median age was 55 years old, including 4 cases of low-grade FDCS and 3 cases of high-grade FDCS. The tumor location of 2 cases was in mediastinum, the tumor locations of others were in nasopharynx, kidney, lung, rectum and liver, respectively. The results of immunohistochemistry showed that, the tumor cells were diffusely or focally positive for CD21, CD23, CD35, D2-40, EGFR and CXCL13, but negative for S-100, CD68, HMB45, SMA, Desmin, CD117, Dog-1, CD34, CD30, EMA and CK.Five cases were positive for PD-L1 and the its expression in high-grade FDCS were higher than that in low-grade FDCS.Two cases of low-grade FDCS were positive for BRAF V600E, but the BRAF V600E mutation weren′t detected in all of 7 cases. The result of EBER in-situ hybridization showed that only the nasopharynx FDCS was positive.The follow-up information of 5 patients were available (7~43 months), 4 patients died and 1 still alive with rectum metastasis.@*Conclusions@#FDCS is a rare malignant disease with relapse and metastatic tendency. The combined applications of the first-line antibodies including CD21, CD23, CD35 and second-line antibodies including D2-40, CXCL13, EGFR are helpful for its diagnosis and differential diagnosis. The high expression of PD-L1 implicates the potential benefit of FDCS patients acquired from immunotherapy.

Radiological features of follicular dendritic cell tumor of spleen / 中华放射学杂志

Objective To summarize the radiological features of follicular dendritic cell tumor of spleen (FDCS).Methods The clinical, radiological and pathological data of 8 patients from November 2011 to November 2017 in 5 hospitals with FDCS confirmed by pathology were retrospectively analyzed. All patients underwent CT examinations including plan and enhanced CT. Three patients underwent additional MRI and two patients underwent PET‐CT examinations simultaneously. The imaging features such as location, number, shape, boundary, size, internal structure, density (or signal, 18F‐fluorodeoxyglucose uptake), enhancement model and the relationship with surrounding structures were observed and compared with pathological results. Results Of the 8 patients with FDCS, 7 were located in the spleen and 1 was located in the spleen of the ectopic spleen of the pancreas. Seven patients with splenic FDCS underwent splenectomy and 1 patient with pancreatic ectopic spleen FDCS underwent resection of the pancreas. Multiple lesions were detected in 1 case, while single in the others. Tumor was round or oval. The tumors were well‐circumscribed and presented as expansive growth. On unenhanced CT, the tumors showed a slightly lower density, and hemorrhage and necrosis could be detected in 6 lesions. Calcification was seen in 1 case, significant necrosis, and cystic change was presented in the pancreatic ectopic spleen FDCS. The solid part presented isointensity or slightly hypointensity on T1WI, and hyperointensity on T2WI. Cystic necrosis areas were hypointensitive on T1WI, and hyperointensitive on T2WI. Spoke‐like areas with hypointensity on T1WI and hyperointensity on T2WI were detected in the center of the solid part with the distribution among the substantial degenerative and necrotic regions. PET‐CT showed that the 18F‐fluorodeoxyglucose was uptaked obviously. The enhancement CT showed that at the arterial phase, the tumors were markedly enhanced and continuously enhanced at portal vein phase and balance phase. Multiple liver metastases were detected in 1 case with huge FDCS. One patient was followed up for 6 years, and gastric lymphoma was detected. The others were followed up for 6 to 53 months, there remained no transfer or recurrence.Conclusions The features of FDCS of spleen mainly manifest as solid or cystic mass with clear solitary sphenoma accompanied by scarring, calcification and hemorrhage. The enhancement mode is persistent enhancement. MRI and PET‐CT help to further reflect the tumor pathological basis and biological characteristics.

Follicular Dendritic Cell Sarcoma - A Case Report

Follicular dendritic cell sarcoma is an uncommon tumor that originates from follicular dendritic cells. The identification and diagnosis of FDCS is not as easy as it has close histological resemblance with non-Hodgkin lymphoma, sarcoma, melanoma, undifferentiated carcinomas, melanoma, and other dendritic or histiocytic cell disease. The definite diagnosis of FDCS can be established with the help of immunohistochemical investigation coupled with imaging modalities such as positron-emission tomography and computed tomography. We present a case of an elderly woman with a history of follicular dendritic tumor. The patient was primarily treated with CHOP chemotherapy in a different hospital. Upon initial investigation in our institution, disease progression was observed. The patient was treated with GEMTAX chemotherapy. The patient showed a partial response to therapy after three cycles of GEMTAX. However, disease progression was observed after six cycles of GEMTAX. The patient was switched to ESHAP, wherein after three cycles partial response to therapy was observed as per PET-CT scans. Despite the use of all three chemotherapy regimens, recurrence was observed. Systemic chemotherapy should be reserved for patients who failed in primary treatment or those with metastatic disease. However, multisite clinical trials should be developed to rationalize optimal treatment strategies for this uncommon disease.

Sarcoma de células dendríticas foliculares: una entidad poco frecuente / Follicular dendritic cell sarcoma: an unsual entity

Los sarcomas de células dendríticas foliculares son neoplasias linfoides extremadamente raras. Afectan primordialmente a ganglios linfáticos con compromiso extranodal ocasional. El diagnóstico defini-tivo requiere inmunohistoquímica. Su comportamiento clínico, el tratamiento, así como su evolución resultan poco conocidos. Presentamos el caso de un paciente al que se le diagnosticó un sarcoma dendrítico folicular con afectación axilar.

Folicular dendritic cell sarcoma is an extremelly rare lymphoid neoplasm. Lymph nodes are predominantly afected, but occasionallu extranodal compromise is seen. Definitive diagnosis requires confirmaton by inmunohistochemistry. The clinical features and management are not well know. We present the case follicular dendritic cell sarcoma with axilary afectaton.

Diagnosis and treatment progress of interdigitating dendritic cell sarcoma / 肿瘤研究与临床

Interdigitating dendritic cell sarcoma (IDCS) is a very rare hematopoietic tissue-derived dendritic cell malignancy. Because of the lack of specific clinical manifestations, pathological diagnosis is still the gold standard for the diagnosis of IDCS. However, there are no standard treatment programs of IDCS at present. Most reports in the literatures on single tumor mainly focus on surgery. And for patients with multiple metastases and relapses in the body, chemotherapy is the major treatment method. IDCS is characterized with high malignancy, rapid clinical progress and poor prognosis. This paper reviews the progress of IDCS diagnosis and treatment.

Sarcoma diseminado de células dendríticas interdigitantes / Disseminated interdigitating dendritic cell sarcoma

Se describe el caso de una mujer de 70 años que consultó por dolor abdominal asociado a pérdida de peso y sudoración nocturna. En el examen físico se destacaban una masa abdominal comprendida entre el epigastrio y el flanco izquierdo, de unos 5 cm de diámetro, duro-elástica, móvil e indolora, y al menos tres adenopatías supraclaviculares bilaterales de 2 cm de diámetro, duras y adheridas a planos profundos. Se realizó una biopsia de la masa abdominal, con lo que se diagnosticó un sarcoma de células dendríticas interdigitantes. Se inició quimioterapia con el esquema CHOP (ciclofosfamida, doxorrubicina, vincristina y prednisona). Falleció luego de completado el primer ciclo del tratamiento, a los seis meses del diagnóstico.

A 70 year-old woman was admitted to our hospital with a 3-month history of abdominal pain, weight loss and night sweats. On physical examination, she presented with a 5 cm diameter abdominal mass extended from epigastrium to the left flank, and at least three bilateral supraclavicular adenopathies. A disseminated interdigitating dendritic cell sarcoma was diagnosed through a biopsy of the abdominal mass. After that, a CHOP regime (cyclophosphamide, doxorubicin, vincristine and prednisone) was iniciated. She died after completion of the first cycle of treatment, six months after diagnosis.

Recurrent Follicular Dendritic Cell Sarcoma of the Parotid Gland Imaged with 18F-FDG PET/CT / 대한핵의학회잡지

Follicular dendritic cell sarcoma (FDCS) is an extremely rare tumor with only 67 cases of head and neck FDCS reported in the literature. A 65-year-old female had a 6-cm follicular dendritic cell sarcoma resected from the left parotid gland with close margins. It recurred 1 year later as a 5-cm mass that was intensely [18F] fluoro-2-deoxy-D-glucose (18F-FDG) avid on positron emission tomography/computed tomography (PET/CT) and was re-excised. A follow-up PET/CT did not show any metastatic disease. The use of 18F-FDG PET/CT in the management of FDCS warrants further research. We present the 18F-FDG PET/CT imaging findings of this rare tumor.

Follicular dendritic cell sarcoma: report of two cases and literature review / Sarcoma de células dendríticas foliculares: relato de dois casos e revisão da literatura

ABSTRACTFollicular dendritic cell sarcoma is a rare neoplasm, first described in 1986 by Monda. Case 1: A female patient, 50-year-old performed abdominal computed tomography scan that detected a tumor lesion of 8.0 cm in the mesentery. She underwent resection of the lesion. Microscopic examination revealed epithelioid neoplasm, interspersed with lymphocytes, and positive immunohistochemical staining for CD21 and CD35. The patient underwent adjuvant chemotherapy. Case 2: A male patient, 21-year-old presented right-sided neck mass measuring 7.0 cm. The biopsy revealed proliferation of spindle cells, interspersed with inflammatory infiltrate and storiform arrangement, and positive immunohistochemical staining for CD21 and CD23. The patient underwent neoadjuvant radiotherapy and surgical resection.

RESUMOSarcoma de células dendríticas foliculares é uma neoplasia rara, descrita pela primeira vez em 1986 por Monda. Caso 1: Paciente do sexo feminino, 50 anos, realizou tomografia computadorizada de abdômen que detectou lesão tumoral de 8,0 cm em mesentério. Foi submetida à ressecção da lesão. A microscopia revelou neoplasia epitelioide, com linfócitos de permeio e expressão imuno-histoquímica de CD21 e CD35. A paciente foi submetida à quimioterapia adjuvante. Caso 2: Paciente do sexo masculino, 21 anos, com massa cervical direita medindo 7,0 cm. A biópsia evidenciou proliferação de células fusiformes, com infiltrado inflamatório de permeio e arranjo estoriforme, com expressão imuno-histoquímica de CD21 e CD23. O paciente foi submetido a radioterapia neoadjuvante e ressecção cirúrgica.

Comparison of diagnostic values of Clusterin, CXCL13, Podoplanin, CD21 and CD35 in foll-cular dendritic cell sarcoma / 临床与实验病理学杂志

Purpose To evaluate the diagnostic values of Clusterin, CXCL13, Podoplanin (D2-40), CD21 and CD35 in follcular den-dritic cell sarcoma. Methods The expression levels of 10 cases of follcular dendritic cell sarcoma ( FDCS) and 12 types of FDCS mimics (83 cases in total) were investigated by immunohistochemical methods, the latter including solitary fibrous tumor, leiomyosar-coma, gastrointestinal stromal tumor and others. The diagnostic validities of the five biomarkers were compared. Results ( 1 ) The positive rates of Clusterin, CXCL13, D2-40, CD21 and CD35 in the FDCS group were 100%, 70%, 60%, 90% and 80%, respec-tively, the corresponding rates in the control group were 30%, 4%, 11%, 2% and 0 in turn. (2) The five biomarkers could be cate-gorized into 3 groups, according to their diagnostic values in FDCS. The first group included CD21 and CD35, which had much higher sensitivities (90%, 80%), specificities (100%, 98%) and accuracies (98%, 96%), compared with the other biomarkers. The second group included CXCL13 and D2-40, which had a relatively lower sensitivities (70%, 60%), specificities (96%, 89%) and accuracies (94%, 86%), compared with CD21 and CD35. The third group included Clusterin, which had the highest sensitivity (100%), while the specificity (70%)and accuracy (73%) were inferior to the first and second groups. (3) The diagnostic values of CD21 and CD35 combination were 100%, 98%, 98%, 83% and 100%, respectively. Conclusions (1) CD21 and CD35 are the most valuable biomarkers for FDCS. The combined diagnostic effect of the two markers is generally superior to that of single marker. (2) Clusterin has the highest sensitivity for FDCS. However, the frequent expression in FDCS mimickers restricts its diagnostic values for FDCS. (3) CXCL13 and D2-40 may be used as a marker for FDCS, but are not recommended as the first selection based on their diagnostic performance. (4) On the reasons that FDCS mimickers may not uncommonly express Clusterin and D2-40, and rarely show positivity for CD21 or CXCL13, more attention should be paid to the phenomenon to avoid misdiagnosis.

Extranodal Follicular Dendritic Cell Sarcoma Involving Tonsil

Follicular dendritic cell sarcoma (FDCS) is a rare neoplasm arising from lymph nodes as well as extranodal sites. Despite the characteristic histopathological features and distinctive immunophenotype, extranodal FDCS are often misdiagnosed initially as undifferentiated carcinoma, inflammatory pseudotumour, meningioma, metastatic malignant melanoma, ectopic thymoma, etc., because of its rarity and lack of awareness. Correct diagnosis of this tumour is imperative given its potential for recurrence and metastasis. We report a case of tonsillar FDCS in a 30-year-old lady who presented with slowly progressing throat pain and dysphagia for a duration of one year. Local examination showed an enlarged left tonsil with an ulceroproliferative growth. The right tonsil was normal. There was no regional lymphadenopathy. Histopathological examination of the tonsillectomy specimen showed a 2.2 x 1.5 cm infiltrative tumour composed of ovoid to spindle cells arranged in characteristic storiform, interlacing fascicular and diffuse patterns. The tumour cells were immunopositive for CD21, CD23, CD35, and S-100 protein and negative for cytokeratin. The Ki-67 antigen-labelling index (Ki-67 LI) was 6%. The EBV status was negative. It was classified as a low risk FDCS. The patient was lost to follow-up after 6 months.

A Case of Disseminated Extranodal Interdigitating Dendritic Cell Sarcoma Arising from Parotid Gland / 고신대학교의과대학학술지

Interdigitating dendritic cell sarcoma (IDCS) is an extremely rare tumor derived from professional antigen presenting cell and primarily found in lymph nodes, with rarer case report about extranodal presentation of IDCS. A 71-yr-old man was admitted with progressively enlarging and painless mass in the right parotid area for 2 months. Computed tomography of the neck and chest revealed enhancing mass in right parotid gland, multiple lymphadenopathies around neck and mediastinum, and an osteolytic metastasis at thoracic spine. Morphological and immunohistochemical analysis of an excisional biopsy specimen from parotid mass were consistent with a diagnosis of IDCS. Palliative chemotherapy with 6 cycles of CHOP (cyclophosphamide, adriamycin, vincristine, and prednisolone) regimen and 2 cycles of ABVD (adriamycin, bleomycin, vinblastine, and dacarbazine) regimen plus radiotherapy on parotid mass failed in tumor reduction. We describe a rare case of disseminated extranodal IDCS arising from parotid gland.

Characteristics,diagnosis and treatment of interdigitating dendritic cell sarcoma / 国际肿瘤学杂志

Interdigitating dendritic cell sarcoma (IDCS)is a rare malignant tumor of the dendritic cell, derived from the hematopoietic tissue.The major clinical manifestation of IDCS is superficial lymphadenopathy, and the enlarged lymph nodes may appear in some atypical ereas,such as the lung,kidney,bladder and the pleura,etc.With the development of the pathological diagnosis and the application of immunohistochemical staining and electron microscopes,the case detection rate is apparently improved.With the high degree of malignant,rapid progress and poor prognosis of the disease,currently,surgical therapy is still the main approach to the treatment of IDCS.

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.

Transformation of Castleman's Disease into Follicular Dendritic Cell Sarcoma, Presenting as an Asymptomatic Intra-abdominal Mass / 대한소화기학회지

Follicular dendritic cell (FDC) sarcoma is an extremely rare malignant neoplasm arising from FDCs. The exact origin of FDCs remains unclear; both a hematopoietic lineage origin and a stromal cell derivation have been proposed. Proliferation of FDCs can lead to benign reactive lesions or generate neoplastic conditions. The lesions are most commonly found in lymph nodes and usually involve the head and neck area. Castleman's disease is a rare non-neoplasitic lymphoproliferative disorder. Rare cases of hyaline-vascular Castleman's disease have been associated with FDC sarcoma, but a clonal relationship has not been convincingly demonstrated. A pathway toward tumor evolution, beginning with hyperplasia and dysplasia of FDCs, has been proposed. Despite this known association between Castleman's disease and FDC sarcoma, there have only been few reported cases of sarcoma arising as a complication of pre-existing Castleman's disease, especially in abdominal lesions. We describe here a 51-year-old female with an FDC sarcoma arising from unicentric, hyaline-vascular type Castleman's disease in an intra-abdominal mass. Pathologically, the lesion showed a series of changes during the process of transformation from Castleman's disease to FDC sarcoma.

Follicular Dendritic Cell Sarcoma of the Omentum: Multidetector Computed Tomography Findings

We report computed tomography (CT) findings for a rare case of follicular dendritic cell sarcoma of the greater omentum from a 47-year-old female patient. The tumor presented ash a palpable mass lesion in the umbilical region for the last two months. Multidetector CT scan of the abdomen showed a 14-cm soft-tissue mass with calcification and necrosis within the greater omentum. As a result, a follicular dendritic cell sarcoma should be considered in the differential diagnosis of a solitary omentum mass, especially one with coarse and chunk-like calcifications.