Angiofollicular lymph node hyperplasia associated with myelofibrosis case report and immunologic marker studies.

A case of angiofollicular lymph node hyperplasia (AFH) (hyaline vascular type) of the mediastinum associated with myelofibrosis is reported with immune marker studies. We hypothesize that the myelofibrosis is more than a mere coincidence since other myeloproliferative disorders have been observed in conjunction with AFH. Immunohistochemistry on cryostat sections of lymph node using the biotin-avidin fluorescence technique showed the presence of numerous T helper cells and very few T suppressor/cytotoxic cells in the parafollicular areas. Concentric rings of lymphocytes showed the phenotype of mantle zone lymphocytes (i.e. IgM, IgD positivity), while the germinal centres were ill-formed as shown by Leu 14 (a Pan B cell marker) staining. By electron microscopy, follicular dendritic reticulum cells were readily found. The above findings suggest an abnormality of germinal center formation.