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hyaline vascular type-Castleman disease

Tuesday 5 January 2010


- hyalin vascular Castleman disease vs follicular lymphoma

Morphological synopsis

- Large follicles, scattered in mass of lymphoid tissue
- marked vascular proliferation
- hyalinization of abnormal germinal centers
- prominent germinal center showing well-developed vascular hyaline changes
- regressively transformed germinal centers
- many large cells with vesicular nuclei in hyaline center are follicular dendritic cells

  • they may become atypical (dysplastic) in abnormal germinal centers and in intervening tissue
  • cytogenetic and molecular evidence of clonality
  • dysplasia of reticular/dendritic cells in Castleman disease. These cells are immunoreactive for desmin.
  • formation of dendritic follicular tumors

- tight concentric layering of lymphocytes at periphery:

  • corresponds to mantle zone
  • results in onion-skin appearance

- Interfollicular stroma:

  • prominent
  • numerous postcapillary venule-type hyperplastic vessels
  • admixture of: plasma cells, eosinophils, immunoblasts
  • KP1-positive plasmacytoid monocytes

- Sinuses characteristically absent

- Vascular and related contractile (myoid) elements in interfollicular tissue:
when unduly prominent designated stroma-rich (stroma-rich variant).

  • prominent stromal component
  • richly vascularized
  • further proliferation of this component results in formation of: angiomyoid proliferative lesions, angiomatous hamartomas or vascular neoplasms, sometimes hemangiopericytoma-like features
  • vascular proliferation in the surrounding soft tissues

Morphological vaiants

- Variant lymphoid subtype:

  • marked expansion of mantle zone
  • small relatively inconspicuous germinal centers
  • merges with process designated mantle zone hyperplasia


- Follicular dendritic cells in hyaline center

  • strong immunoreactivity for CD21 and CD35
  • Prominent network of CD21-positive dendritic follicular cells in the abnormal germinal center of Castleman’s disease.

- Polyclonal immunoglobulin production by plasma cells
- Large numbers of suppressor T cells in interfollicular areas
- An aberrant phenotype of Ki-B3-negative B lymphocytes in mantle zone cells
- FVIII-related antigen: strong positivity in endothelium of interfollicular vessels, weak and focal reaction in hyalinized vessels in center of follicles

Differential diagnosis

- angioimmunoblastic lymphadenopathy

- Large follicles have been confused with:

  • Hassall corpuscles resulting in misdiagnosis of thymoma
  • splenic white pulp resulting in misdiagnosis of ectopic spleen

- Variant lymphoid subtype: more likely to be confused with malignant lymphoma of follicular or mantle cell type.

See also

- Castleman disease

  • plasma cell type of Castleman disease