Dendritic Cells ; pathology ; Humans ; Leukemia, Myeloid ; pathology ; Plasmacytoma ; pathology

Dendritic Cells ; pathology ; Hematologic Neoplasms ; pathology ; Humans ; Skin

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

Dendritic Cells ; pathology ; Hematologic Neoplasms ; diagnosis ; therapy ; Humans

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

A 7-year-old girl was admitted to Xiangya Hospital due to systemic lymphadenectasis for 2 months and skin ecchymosis for 3 days. Nine months ago, the girl experienced painless nodules in the left lower extremity with no apparent causes. Three months later, dermatorrhagia and ecchymosis occurred in many regions such as the periocular areas, conjunctiva, oral mucosa, perineal area, and groin, with a "raccoon sign" in both eyes; superficial lymphadenectasis and hepatosplenomegaly were also observed in many regions. The pathological sections for the skin nodules showed malignant tumors in lymphohematopoietic cells, and in combination with clinical manifestations, immunohistochemistry, and positive results for CD4, CD56, and CD123 by bone marrow flow cytometry, the girl was diagnosed with blastic plasmacytoid dendritic cell neoplasm. Then high-risk ALL regimen was applied as the chemotherapy for this girl. At present, the girl has been followed up for 3 months; ecchymosis has disappeared, and the enlarged lymph nodes have shrunk. No abnormal cells have been found in bone marrow morphological examination, and bone marrow flow cytometry has shown that primitive precursor cells account for 1.5% and express CD33, CD34, CD123, and CD117.
Child ; Dendritic Cells ; pathology ; Ecchymosis ; pathology ; Female ; Humans ; Neoplasm Invasiveness ; Skin ; pathology ; Skin Neoplasms ; pathology

OBJECTIVE: To investigate the clinicopathological features of blastic plasmacytoid dendritic cell neoplasm (BPDCN). METHODS: A total of 13 cases of BPDCN diagnosed in Peking University First Hospital from January 2013 to March 2022 were collected. The clinical features, histopathological characteristics, immunophenotypes and prognosis of the patients were analyzed retrospectively, and the related literatures was reviewed as well. RESULTS: Among the 13 patients, 11 were male and 2 were female, with a median age of 62 years (ranging from 5 to 78 years). Among them, single organ involvement occurred in 5 cases, all of which presented with skin lesions. Two or more organs were involved in other 8 cases (single organ with bone marrow involved in 3 cases; skin, bone marrow and lymph node involved simultaneously in 3 cases; skin, bone marrow, lymph node and spleen involved simultaneously in 2 cases). Histopathologically, it was characterized by the proliferation of medium to large atypical blastic cells, which infiltrated the whole thickness of dermis. When involved, the bone marrow lesions mainly appeared in a diffuse pattern, while the lymph node structure was usually destroyed, and the red pulp of the affected spleen was diffusely invaded. Immunohistochemical staining showed that all the 13 cases were positive for CD4, CD56, and CD123 (13/13) in varying degrees. All the 9 cases expressed TCL1 (9/9). Variable expression of CD68 (KP1) (8/13), TdT (7/12), CD117 (2/6), and high Ki-67 proliferation index (40%~80%) were showed. The neoplastic cells lacked expressions of CD20, CD3, MPO, CD34, or CD30; EBER in situ hybridization were negative (0/9). After definite diagnosis, 6 cases received chemotherapy, among which 1 received adjuvant radiotherapy, and 2 received subsequent bone marrow transplantation. Another 2 cases only received maintenance treatment. The median follow-up time was 14 months (ranging from 6 to 36 months), 5 patients died of the disease (6 to 18 months), 3 patients survived (7 to 36 months up to now), and the remaining 5 patients lost follow-up. CONCLUSION BPDCN is a rare type of malignant lymphohematopoietic tumor with aggressive behavior and poor prognosis. The diagnosis should be made combining clinical features, histopathology, and immunohistochemical phenotype. Attention should be paid to differentiating BPDCN from other neoplasms with blastoid morphology or CD4+CD56+ tumors.
Male ; Female ; Humans ; Hematologic Neoplasms ; Retrospective Studies ; Dendritic Cells ; Skin Neoplasms/pathology* ; Skin/pathology*

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

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

Dendritic Cells ; pathology ; Histiocytes ; pathology ; Histiocytosis, Langerhans-Cell ; pathology ; Humans ; Keratins ; analysis ; Langerhans Cells ; pathology ; Lymphoma, Large B-Cell, Diffuse ; pathology ; Sarcoma ; chemistry ; classification ; pathology