No abstract available.
Animals ; Germinal Center* ; Lymph Nodes* ; Mice*

No abstract available.
Animals ; Erythrocytes* ; Germinal Center* ; Mice* ; Sheep* ; Spleen*

OBJECTIVETo improve the understanding of progressive transformation of lymph node germinal centers (PTGC) and to explore its clinical, histopathologic and immunohistochemical features and the differential diagnosis between the related disease of germinal center hyperplasia.

METHODSThe clinical manifestation, laboratory bindings, treatment and outcome of a patient with PTGC were presented.

RESULTSThe main manifestation of the patient was painless peripheral lymphadenopathy. Histopathologic examination of an axillary lymph node showed reactive follicular hyperplasia and the progressive transformation changes germinal centers. The borderline between the germinal center and the mantle layer was obscured. The cells in the progressive transforming germinal centers were positive for CD20(+), CD5(+), CDw75(+).

CONCLUSIONPTGC is a rare lymphoid disorder. Histopathology and immunohistochemistry are important basis of the diagnosis.

Micronodular thymoma with lymphoid stroma (MNT) is an extremely rare tumor and has not been reported in Korea. Herein, we report a case of MNT diagnosed in a 75 year-old male. The mass was incidentally identified on thoracic computer tomography (CT) during work-up for a cardiac mass. The resected thymic mass was ovoid and solid measuring 3.5x3 cm in size and showed homogenously white tan, solid and firm cut surface. Microscopically, the tumor had a thin fibrous capsule except small foci of invasion to thymic adipose tissue, and consisted of characteristic multiple discrete epithelial nodules in abundant lymphoid stroma. The epithelial nests anastomosed each other, forming a vague cord-like structure. The cells in the epithelial nests were bland, spindle to oval shape with relatively abundant cytoplasm, slightly vesicular chromatin and one definite nucleolus. The lymphoid stroma contained prominent germinal centers. No evidence of recurrence or metastasis has been found within 4 years of surgery.
Adipose Tissue ; Chromatin ; Cytoplasm ; Germinal Center ; Humans ; Korea ; Male ; Neoplasm Metastasis ; Recurrence ; Thymoma ; Triacetoneamine-N-Oxyl

The pseudolymphoma of the skin has the architectural and cytological features of a neoplastic proliferation of lymphoid tissue but pursue a benign course. Cutaneous B cell pseudolymphoma (CBPL) shares many histopathologic and clinical features with cutaneous B cell lymphoma (CBCL). Therefore, the differentiation between CBPL and CBCL is often very difficult, but it is important because each of them has a different therapeutic consequence. Recently, immunoglobulin gene rearrangement is considered as a reliable technique for differentiation of CBPL with CBCL. We herein report a case of idiopathic lymphocytoma cuffs, showing a typical nodular infiltrate of lymphocytes that formed a follicular germinal center resembling reactive lymph nodes with numerous tingible bodies, and that revealed a polyclonality in the immunoglobulin gene rearrangement.
Genes, Immunoglobulin ; Germinal Center ; Lymph Nodes ; Lymphocytes ; Lymphoid Tissue ; Lymphoma, B-Cell ; Pseudolymphoma* ; Skin

A Case of pseudolymphoma involving the cavernous sinus in a 38-year-old male patient is reported. The patient was admitted because of intermittent diplopia and left side facial sensory change. The tumor was well demarcated, homogeneously enhancing mass in the left side cavernous sinus on MRI. The histopathological findings showed diffuse and dense infiltration of lymphocytes in connective tissue stroma without forming lymphoid follicle or germinal center and the infiltrating lymphocytes were well differentiated and matured. We report a rare case of pseudolymphoma arising in the cavernous sinus, which revealed polyclonal differentiation of lymphocytes confirmed the diagnosis of pseudolymphoma.
Adult ; Cavernous Sinus* ; Connective Tissue ; Diagnosis ; Diplopia ; Germinal Center ; Humans ; Lymphocytes ; Magnetic Resonance Imaging ; Male ; Pseudolymphoma*

BACKGROUND: Follicular lymphomas present with various immunohistologic patterns. The immunohistochemical markers used in the diagnosis of follicular lymphoma show variable degrees of sensitivity and specificity, and thus, additional germinal center markers are required. Smad1 has been reported to be overexpressed in follicular lymphoma, but little is known regarding the expression patterns of Smad proteins in human lymphoid tissue. METHODS: In the present study, we performed immunohistochemistry for traditional germinal center markers and for Smad1 in human reactive lymphoid and follicular lymphoma tissues to investigate Smad1's usefulness in the diagnosis of follicular lymphoma. RESULTS: In the reactive germinal centers, most cells were positive for Smad1. Among the 27 follicular lymphoma cases, 17 of 21 (80%) were Smad1 positive, 17 of 27 (63%) were positive for CD10, and 23 of 27 (85%) were positive for Bcl6. Notably, three cases expressed CD10 only, and one only expressed Bcl6. All these cases were grade 3 tumors and showed follicular and diffuse growth patterns. CONCLUSIONS: These results indicate that Smad1 is a candidate as a germinal center marker. Furthermore, they suggest that the Smad signaling pathway might be involved in follicular lymphoma.
Diagnosis ; Germinal Center ; Humans ; Immunohistochemistry ; Lymphoid Tissue ; Lymphoma ; Lymphoma, Follicular* ; Sensitivity and Specificity ; Smad Proteins

Kimura's disease is a rare benign disease characterized by subcutaneous or dermal tumors occurring predominantly on the head and the neck. It usually occurs in young adults without constitutional symptoms, except for peripheral blood eosinophilia. The histopathologic features of the tumor are characterized by dense lymphoid aggregates containing a prominent germinal center and by the proliferation of endothelial cells associated with varying degrees of lymphocytic, histiocytic, and eosinophilic infiltration. We report a case of Kimura's disease without peripheral blood eosinophilia in a 24-year-old male who had had a painless and slowly growing tumor-like swelling on his right groin for one year. The mass was excised, and the specimen was confirmed as Kimura's disease. After surgical excision, the lesion recurred, so 30 mg of oral prednisone was given daily for one month and then decreased gradually for another one month. Now, the lesion is completely healed.
Endothelial Cells ; Eosinophilia ; Eosinophils ; Germinal Center ; Groin* ; Head ; Humans ; Male ; Neck ; Prednisone ; Young Adult

Understanding germinal center reactions is crucial not only for the design of effective vaccines against infectious agents and malignant cells but also for the development of therapeutic intervention for the treatment of antibody-mediated immune disorders. Recent advances in this field have revealed specialized subsets of T cells necessary for the control of B cell responses in the follicle. These cells include follicular regulatory T cells and Qa-1-restricted cluster of differentiation (CD)8+ regulatory T cells. In this review, we discuss the current knowledge related to the role of regulatory T cells in the B cell follicle.
Germinal Center ; Immune System Diseases ; T-Lymphocytes ; T-Lymphocytes, Helper-Inducer ; T-Lymphocytes, Regulatory* ; Vaccines

Lymphoid polyp is a very rare disease that commonly occurs in the rectum. It is a benign, focal or diffuse lesion that typically occurs where clusters of lymphoid follicles are present. The polyp is composed of well differentiated lymphoid tissue. It can generally be differentiated from malignant lymphoma by the proliferation of normal lymphoid tissue, which has a prominent follicular pattern and a clearly defined germinal center. There have been only a few reports of lymphoid polyps of the rectum, and there have been no reports of lymphoid polyp in the ampulla of Vater. We experienced a case of lymphoid polyp in the ampulla of Vater associated with tubulopapillary adenoma, and the patient first presented with jaundice, weight loss and general weakness.
Adenoma ; Ampulla of Vater ; Germinal Center ; Humans ; Jaundice ; Lymphoid Tissue ; Lymphoma ; Polyps ; Rare Diseases ; Rectum ; Weight Loss