"Hyalinizing spindle cell tumor with giant rosettes" (HSCTGR) is a recently described tumor, which is regarded as an unusual variant of low-grade fibromyxoid sarcoma. Proof of a metastatic potential was lacking. The patient in the report was a 35-yr-old woman who showed multiple bilateral pulmonary nodules with massive pleural effusion in the right side. She had a history of a mass excision in the right thigh 11 yrs ago at another hospital, which was reported as a "leiomyoma". Two years before this presentation, the patient received a routine chest radiograph which demonstrated bilateral multiple pulmonary nodules. A lobectomy of the left upper lung was performed. The histological findings revealed a well-circumscribed nodule that was characterized by a spindle-shaped fibrous to hyalinized stroma with criss-crossing short fascicles and giant collagen rosettes surrounded by a rim of spindle-shaped cells. Electron microscopy confirmed the fibroblastic nature of the tumor. This case, in addition to at least two other cases reported in the literature, demonstrates that the HSCTGR is a malignant neoplasm with the capacity to metastasize after a long hiatus.
Adult ; Female ; Humans ; Hyalin/metabolism ; Korea ; Lung Neoplasms/diagnosis/*pathology/*secondary/ultrastructure ; *Neoplasm Metastasis ; Pleural Effusion/pathology ; Sarcoma/diagnosis/*pathology/ultrastructure ; Thigh/pathology ; Time Factors

OBJECTIVETo study the clinical pathological features and immunophenotype of follicular dendritic cell sarcoma (FDCS) with discussion on its diagnostic clues to improve diagnostic level.

METHODSFive cases of FDCS were analyzed by clinical, pathologic and immunohistochemistry methods.

RESULTSFive cases of FDCS were located in the cervical lymph node. Microscopically, the normal architectures were effaced by ovoid, spindle-shaped with fascicular, diffuse or whorled patterns and with rich lightly eosinophilic cytoplasm, syncytial appearance. Nuclei tend to show irregular clustering, scattered multinucleated giant cell. Nucleoli often distinct, sometimes prominent. Mitotic count variable, may show significant cellular pleomorphism. Immunohistochemical studies show that the tumor cells were positive for CD21, CD35, but negative for CD1a, CD34, CK and HMB45. Under electron microscopy, the tumor cells possessed long villus cytoplasmic processes and desmosome-like junctions, Birbeck granules were absent.

CONCLUSIONSFDCS is a rare malignant tumor and differential diagnosis includes Langerhans cell sarcoma, interdigitating dentric cell sarcoma, malignant fibrous histocytoma, melanoma, metastatic spindle cell carcinoma and others. Immunohistochemistry and electron microscopy are necessary for a correct diagnosis.

Adult ; Dendritic Cell Sarcoma, Follicular ; metabolism ; pathology ; Diagnosis, Differential ; Female ; Follow-Up Studies ; Humans ; Immunohistochemistry ; Lymph Nodes ; metabolism ; pathology ; ultrastructure ; Male ; Microscopy, Electron ; Middle Aged ; Receptors, Complement 3b ; metabolism ; Receptors, Complement 3d ; metabolism