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.

Solitary Fibrous Tumours/Hemangiopericytomas of the Maters(Meninx):A Clinicopathologic Analysis / 中国医学科学院学报

To study the clinicopathologic characteristics,immunohistochemical features,differential diagnosis,and prognosis of solitary fibrous tumours(SFT)/hemangiopericytomas(HPC)in the maters(meninx). Methods A series of 7 cases previously diagnosed as SFT/HPC at the Department of Pathology,Peking Union Medical College Hospital,during the period from 2008 to 2018 were analyzed for clinical data,histopathology,and immunohistochemical findings.The patients were followed up and the relevant literatures were reviewed. Results These seven patients included two males and 5 females aged 22 to 77 years(mean,49 years).Headache was the most common symptom.The magnetic resonance imaging of SFT/HPC showed irregularly contoured masses and dural tail sign was observed at the periphery of the lesion in 4 cases.The major axis of the tumor ranged from 1.8 cm to 10 cm(mean,4 cm).The tumors were located in the mater in 6 cases and in the spinal meninx in 1 case.The tumors were surgically removed in all cases.Under light microscope,the tumors were formed by long round,oval or spindle cells,with rich branching vascular pattern and varying quantity of collagenous fibers bands in both sparse areas and dense areas.According the WHO classification,2 cases were in WHO grade Ⅰ,2 cases in WHO grade Ⅱ,and 3 cases in WHO grade Ⅲ.Immunohistochemistry of the paraffin-embedded tissues in all cases showed positive immunoreativity for CD34 and vimentin in all seven cases,along with positive signal transducer and activator of transcription 6 in 4 cases,negative epithelial membrane antigen and S-100 in 7 cases,and negative progestational hormone and somatostatin receptor 2 in 6 cases.The Ki-67 index ranged from 1% to 15%.Five patients with follow-up data(including 1 current case)were alive,while 2 patients were lost to follow-up. Conclusions The SFT/HPC are rare in the maters(meninx)and is clinically difficult to be differentiated from other meningioma.The combination of CD34 and signal transducer and activator of transcription 6 helps to diagnose this disease.