Interdigitating dendritic cell sarcoma (IDCS) is an extremely rare neoplasm arising from the antigen-presenting cells of the immune system. This disease usually involves the lymph nodes, and rarely, extranodal sites may be affected. The authors report a case of extranodal IDCS presenting in the pleura. A 32-yr-old man presented with progressive chest pain. Imaging studies showed diffuse pleural thickening with pleural effusion. Morphological and immunohistochemical analysis of an incisional biopsy of the pleura were consistent with a diagnosis of IDCS; tumor cells were positive for S100 and CD45, but negative for CD1a, CD21, CD35, B cell and T cell markers. The patient was administered chemotherapy, but died of progressive disease. Although its incidence is extremely rare, this case suggests that extranodal IDCS should be considered in the differential diagnosis of undifferentiated neoplasms and that immunohistochemical staining be performed using appropriate markers.
Adult ; Dendritic Cell Sarcoma, Interdigitating/diagnosis/*pathology ; Fatal Outcome ; Humans ; Male ; Pleura/*pathology ; Pleural Neoplasms/diagnosis/*pathology ; Tumor Markers, Biological

OBJECTIVETo study the pathologic features, diagnosis and differential diagnosis of interdigitating dendritic cell sarcoma (IDCS).

METHODSThe clinical findings, morphologic features and immunophenotype of 3 cases of IDCS were investigated.

RESULTSGross examination showed that IDCS had a greyish-white to greyish-yellow cut surface. The site of occurrence included lung, spleen (with lymph node metastasis) and lymph node. Histologically, the tumor cells were arranged in nests, fascicles and whorls, with intimate admixture of many lymphocytes and plasma cells. They were oval to spindle in shape and contained pale eosinophilic cytoplasm, oval and sometimes grooved nuclei, small distinct nucleoli and ill-defined cell borders. Immunohistochemical study showed that the tumor cells expressed S-100 protein.

CONCLUSIONSIDCS is a rare type of histiocytic and dendritic cell malignancy with distinctive morphologic findings. It needs to be distinguished from follicular dendritic cell sarcoma, inflammatory pseudotumor, Langerhans' cell histiocytosis, malignant melanoma, undifferentiated carcinoma and anaplastic large cell lymphoma. Immunohistochemical staining for S-100 protein is helpful in confirming the diagnosis.

Adolescent ; Carcinoma ; pathology ; Dendritic Cell Sarcoma, Follicular ; pathology ; Dendritic Cell Sarcoma, Interdigitating ; diagnosis ; pathology ; Dendritic Cells ; pathology ; Diagnosis, Differential ; Female ; Humans ; Lymph Nodes ; pathology ; Lymphatic Metastasis ; pathology ; Male ; Middle Aged ; S100 Proteins ; analysis ; immunology ; Young Adult

OBJECTIVETo study the clinicopathologic features of follicular dendritic cell sarcoma (FDCS) and its differential diagnosis.

METHODSTen cases of FDCS were studied by light microscopy, immunohistochemistry and in-situ hybridization. The clinical features and follow-up information were analyzed.

RESULTSAmongst the 10 cases of FDCS studied, the male-to-female ratio was 1:1. The mean age of the patients was 42 years. Six of them were located in cervical and peritoneal lymph nodes and four in extranodal sites (including tonsil, pelvic cavity, tail of pancreas and spleen). Histologically, the tumor cells had whorled, storiform or diffuse growth patterns. They were spindle in shape and contained syncytial eosinophilic cytoplasm, with round or oval nuclei, vesicular chromatin, distinct nucleoli and a variable number of mitotic figures. Multinucleated tumor giant cells and intranuclear pseudoinclusions were occasionally seen. There was a sprinkling of small lymphocytes and neutrophils within the tumor as well as in the perivascular region. Immunohistochemical study showed that the tumor cells were diffusely or focally positive for CD21, CD23, CD35 and D2-40, but negative for LCA, CD20, CD3, CD1a, HMB45 and CK. Some of them showed EMA, CD68 and S-100 reactivity. In-situ hybridization for Epstein-Barr virus-encoded RNA (EBER) showed positive signals in only one case (which was diagnosed as inflammatory pseudotumor-like FDCS). Of the 7 patients with follow-up information available (duration: 2 months to 39 months; mean: 14 months), 2 cases with paraneoplastic pemphigus died of pulmonary infection at 5 and 7 months respectively. The remaining 5 patients were alive and disease-free after surgical excision (+/- chemotherapy and radiotherapy).

CONCLUSIONSFDCS is a rare low to intermediate-grade malignant tumor. Appropriate application of FDC markers, such as CD21, CD35 and D2-40, would be helpful for arriving at a correct diagnosis. Most cases are associated with good prognosis after surgical treatment, with or without chemotherapy and radiotherapy. Patients with paraneoplastic pemphigus carry a less favorable prognosis.

Adult ; Antibodies, Monoclonal, Murine-Derived ; metabolism ; Dendritic Cell Sarcoma, Follicular ; complications ; metabolism ; pathology ; surgery ; Dendritic Cell Sarcoma, Interdigitating ; pathology ; Diagnosis, Differential ; Female ; Follow-Up Studies ; Humans ; Lymph Node Excision ; Lymph Nodes ; pathology ; surgery ; Male ; Meningioma ; pathology ; Middle Aged ; Nasopharyngeal Neoplasms ; pathology ; Paraneoplastic Syndromes ; complications ; Pemphigus ; complications ; Receptors, Complement 3b ; metabolism ; Receptors, Complement 3d ; metabolism ; Receptors, IgE ; metabolism ; Tonsillar Neoplasms ; metabolism ; pathology ; surgery ; Young Adult

Abdominal Neoplasms ; drug therapy ; metabolism ; pathology ; secondary ; surgery ; Dendritic Cell Sarcoma, Follicular ; drug therapy ; metabolism ; pathology ; surgery ; Dendritic Cell Sarcoma, Interdigitating ; metabolism ; pathology ; Diagnosis, Differential ; Female ; Gastrointestinal Stromal Tumors ; metabolism ; pathology ; Histiocytoma, Malignant Fibrous ; metabolism ; pathology ; Humans ; Middle Aged ; Neoplasm Recurrence, Local ; Omentum ; Peritoneal Neoplasms ; secondary ; Receptor, Epidermal Growth Factor ; metabolism ; Receptors, Complement 3b ; metabolism ; Receptors, Complement 3d ; metabolism

OBJECTIVETo study the clinicopathologic characteristics and diagnostic criteria of interdigitating dendritic cell sarcoma/tumor (IDCS/T).

METHODSThe clinical features, histologic findings and results of immunohistochemical study in six cases of IDCS/T were analyzed, with review of literature.

RESULTSThe age of patients ranged from 20 to 68 years. The sites of involvement included lymph node, tonsil and soft tissue. Histologically, the tumor cells were arranged in sheets, fascicles or whorls and intimately admixed with abundant lymphocytes and plasma cells. They were oval to spindly in shape and contained pale eosinophilic cytoplasm, oval nuclei and distinct nucleoli.Immunohistochemical study showed that the tumor cells were positive for S-100 protein and CD68.

CONCLUSIONSIDCS/T is a rare malignant tumor with poor prognosis. It carries distinctive histologic pattern and immunophenotype. The entity needs to be distinguished from follicular dendritic cell sarcoma/tumor, anaplastic large cell lymphoma and other spindle cell sarcomas in occurring soft tissue.

Adult ; Aged ; Antigens, CD ; metabolism ; Antigens, Differentiation, Myelomonocytic ; metabolism ; Dendritic Cell Sarcoma, Follicular ; metabolism ; pathology ; Dendritic Cell Sarcoma, Interdigitating ; metabolism ; pathology ; Diagnosis, Differential ; Female ; Follow-Up Studies ; Histiocytoma, Malignant Fibrous ; metabolism ; pathology ; Histiocytosis, Langerhans-Cell ; metabolism ; pathology ; Humans ; Lymph Nodes ; pathology ; Lymphoma, Large-Cell, Anaplastic ; metabolism ; pathology ; Male ; Middle Aged ; Neck ; S100 Proteins ; metabolism ; Sarcoma ; pathology ; Soft Tissue Neoplasms ; metabolism ; pathology ; Thigh ; Tonsillar Neoplasms ; metabolism ; pathology ; Vimentin ; metabolism ; Young Adult

Antigens, CD ; metabolism ; Antigens, Differentiation, Myelomonocytic ; metabolism ; Dendritic Cell Sarcoma, Follicular ; metabolism ; pathology ; Dendritic Cell Sarcoma, Interdigitating ; metabolism ; pathology ; surgery ; Diagnosis, Differential ; Granuloma ; metabolism ; pathology ; surgery ; Head and Neck Neoplasms ; metabolism ; pathology ; surgery ; Humans ; Leukocyte Common Antigens ; metabolism ; Lymph Nodes ; metabolism ; pathology ; Lymphoma, Large-Cell, Anaplastic ; metabolism ; pathology ; Lymphoma, T-Cell ; metabolism ; pathology ; Male ; Middle Aged ; Neoplasms, Multiple Primary ; metabolism ; pathology ; surgery ; Receptors, Cell Surface ; metabolism ; S100 Proteins ; metabolism ; Tonsillar Neoplasms ; metabolism ; pathology ; secondary