Carcinosarcoma ; pathology ; Dendritic Cells, Follicular ; pathology ; Humans ; Immunohistochemistry ; Male ; Middle Aged ; Parotid Neoplasms ; pathology ; Sarcoma ; pathology

The 5th edition of the World Health Organization classification of hematolymphoid tumors (WHO Blue Book) is soon to be published. Significant revisions have been made in the chapters on histiocytic/dendritic cell neoplasms and stroma-derived neoplasms of lymphoid tissues, leading to the reclassification and renaming of specific diseases. This article provides a concise interpretation and summary of these updates, highlighting the differences from the fourth edition. Pertinent changes from clinical pathological diagnosis to treatment and prognosis are explored, with an emphasis on recent advancements in molecular genetics. Newly introduced disease classifications are discussed, and the section on follicular dendritic cell sarcoma contributed by the author is detailed to assist readers in quickly understanding and assimilating the new classification standards.
Humans ; Lymphoid Tissue/pathology* ; Soft Tissue Neoplasms/pathology* ; Dendritic Cell Sarcoma, Follicular/pathology* ; Dendritic Cells/pathology* ; World Health Organization

Abdominal Neoplasms ; pathology ; surgery ; Dendritic Cells, Follicular ; pathology ; Humans ; Male ; Middle Aged ; Pharyngeal Neoplasms ; pathology ; surgery ; Sarcoma ; pathology ; surgery

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 inflammatory pseudotumor-like follicular dendritic cell tumor of spleen.

METHODSOne case of inflammatory pseudotumor-like follicular dendritic cell tumor of spleen was examined macroscopically and microscopically. Immunohistochemical study for CD21, CD23, CD35, clusterin, S-100 protein, vimentin, smooth muscle actin, CD1a, CD68, ALK protein, CD30, CD31, CD34, CD3 and CD20 was performed on formalin-fixed, paraffin-embedded sections by standard EnVision method. In-situ hybridization for Epstein-Barr virus (EBV)-encoded RNA was also carried out.

RESULTSMacroscopically, inflammatory pseudotumor-like follicular dendritic cell tumor was large in size, tan-colored, soft to rubbery in consistance and associated with central hemorrhage and necrosis. Histological examination showed scattered follicular dendritic cells admixed with abundant lymphocytes and plasma cells in the background, simulating inflammatory pseudotumor. On high-power magnification, the follicular dendritic cells possessed a moderate amount of pale to lightly eosinophilic cytoplasm, with indistinct cell borders. The nuclei were ovoid or spindly, with vesicular or stippled chromatin and small distinct, often centrally located, nucleoli. Some of the tumor cells showed nuclear pleomorphism and contained irregular foldings of nuclear membrane, coarse chromatin and prominent eosinophilic nucleoli. Mitotic figures were rarely identified. Immunohistochemical study showed that the tumor cells were positive for vimentin, clusterin, smooth muscle actin and CD68. They were weakly and focally positive for CD35 and S-100 protein, but negative for CD21, CD23, CD1a, ALK protein, CD30, CD31 and CD34. Most of the background lymphocytes were of T-lineage (CD3-positive) ,some were CD20 (B-cell marker)-positive. EBV RNA was demonstrated in the tumor cells by in-situ hybridization analysis.

CONCLUSIONSInflammatory pseudotumor-like follicular dendritic cell tumor is a rarely encountered low-grade malignancy with distinctive morphologic pattern. It is associated with EBV infection.

Adult ; Antigens, CD ; Antigens, Differentiation, Myelomonocytic ; Dendritic Cell Sarcoma, Follicular ; pathology ; physiopathology ; Dendritic Cells, Follicular ; pathology ; Female ; Granuloma, Plasma Cell ; etiology ; Herpesvirus 4, Human ; genetics ; immunology ; isolation & purification ; Humans ; Splenic Neoplasms ; pathology ; physiopathology

Chromosomes, Human, Pair 14 ; Chromosomes, Human, Pair 18 ; Dendritic Cells, Follicular ; metabolism ; pathology ; Humans ; Lymphoma, Follicular ; genetics ; metabolism ; pathology ; Lymphoma, Large B-Cell, Diffuse ; genetics ; metabolism ; pathology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Translocation, Genetic

OBJECTIVETo investigate clinicopathologic features, immunophenotypes and differential diagnoses of follicular dendritic cell sarcoma/tumor (FDCS).

METHODSEight cases of FDCS were studied using histological and immunohistochemical examinations and EBER in situ hybridization, with a review of the related literatures.

RESULTSThere were 5 male and 3 female patients with a median age of 50 years. The sites of involvement included lymph node (4 cases), tonsil, nasopharynx, liver, and spleen (1 case each, respectively). The predominant microscopic features histologically included storiform, fascicular, diffuse, whorled and nodular in patterns. The neoplastic cells, dispersed by the infiltrated small lymphocytes, were characterized by abundant eosinophilic or fine granular cytoplasm with indistinct cell borders, and syncytial in appearance. The nuclei of the tumors were ovoid, round to spindled in shape with vesicular or stippled chromatin and small distinct nucleoli. Mitotic figures varied among cases. Pseudovascular spaces and perivascular cuffing were observed in some cases. One case of FDCS involving lesion in liver showed a background of abundant lymphocytes mixing with dispersed spindle or ovoid neoplastic cells having delicate chromatin, mild nuclear atypia, irregular/vesicular nuclei and distinct nucleoli. The neoplastic cells were positive for CD21, CD35, clusterin, and weakly positive for CD68, EMA, S-100 and EGFR. Ki-67 stain showed a variable expression among cases. EBER was positive in 2 cases.

CONCLUSIONSFDCS is a rare malignant tumor with a tendency to relapse and metastasis. Combined morphological and immunophenotypical analysis is necessary to reach a correct diagnosis.

Adult ; Aged ; Antigens, CD ; analysis ; immunology ; Antigens, Differentiation, Myelomonocytic ; analysis ; immunology ; Dendritic Cell Sarcoma, Follicular ; metabolism ; pathology ; Dendritic Cells ; pathology ; Female ; Giant Cells ; Humans ; Immunophenotyping ; methods ; Male ; Middle Aged ; Receptors, Complement 3d ; analysis ; immunology ; Treatment Outcome

Dendritic Cells, Follicular ; pathology ; Diagnosis, Differential ; Humans ; Leukemia, Lymphocytic, Chronic, B-Cell ; pathology ; Lymphoma ; pathology ; Lymphoma, Extranodal NK-T-Cell ; pathology ; Lymphoma, Follicular ; pathology ; Lymphoma, Large B-Cell, Diffuse ; pathology ; Lymphoma, Large-Cell, Anaplastic ; pathology ; Lymphoma, Mantle-Cell ; pathology ; Lymphoma, T-Cell, Peripheral ; pathology ; Neoplasm Invasiveness ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; pathology

OBJECTIVETo study the morphologic and immunophenotypic features of angioimmunoblastic T-cell lymphoma (AITL), as well as the origin of the proliferative follicular dendritic cells (FDCs) in AITL.

METHODSImmunohistochemical study for CD10, CXCL13, bcl-6 and CD21 was performed on 29 cases of AITL. Double immunostaining for bcl-6/CD3, CD10/CD21 and CD10/CD20 were also carried out. Cases of peripheral T-cell lymphoma, unspecified, extranodal NK/T-cell lymphoma, nasal-type, enteropathy-type T-cell lymphoma, anaplastic large cell lymphoma, subcutaneous panniculitis-like T-cell lymphoma and reactive lymphoid proliferation were selected as controls.

RESULTSAmongst the 29 cases of AITL studied, 75.9% (22/29) showed aberrant expression of CD10, while all except one of the controlled cases were negative, 82.8% (24/29) of the AITL cases expressed CXCL13, while all cases of peripheral T-cell lymphoma, unspecified were negative. As for bcl-6 staining, although the highest percentage of bcl-6-positive cells was observed in AITL, the expression pattern was not useful in differentiating AITL from peripheral T-cell lymphoma, unspecified and lymphoid reaction. Besides, all cases of AITL demonstrated the characteristic proliferation of follicular dendritic cells. Two of the cases, which contained obvious germinal centers, had the follicular dendritic cell meshwork extending beyond the lymphoid follicles.

CONCLUSIONSAs compared with bcl-6, CD10 and CXCL13 are specific and sensitive markers in diagnosing AITL. Part of the proliferative FDCs in AITL may originate from the germinal centers.

Adult ; Aged ; Chemokine CXCL13 ; metabolism ; Dendritic Cells, Follicular ; metabolism ; pathology ; ultrastructure ; Female ; Humans ; Immunoblastic Lymphadenopathy ; metabolism ; pathology ; Immunophenotyping ; Lymphoma, T-Cell, Peripheral ; metabolism ; pathology ; Male ; Middle Aged ; Neprilysin ; metabolism ; Proto-Oncogene Proteins c-bcl-6 ; metabolism ; Receptors, Complement 3d ; metabolism

Antiviral Agents ; therapeutic use ; Castleman Disease ; drug therapy ; metabolism ; pathology ; virology ; Dendritic Cells, Follicular ; pathology ; Herpesviridae Infections ; virology ; Herpesvirus 8, Human ; isolation & purification ; Humans ; Interleukin-6 ; blood ; Receptor, Epidermal Growth Factor ; metabolism