Pulmonary nodular lymphoid hyperplasia (pulmonary pseudolymphoma): the significance of increased numbers of IgG4-positive plasma cells.

On the basis of an initial case, we hypothesized that IgG4-positive plasma cells may be increased in pulmonary nodular lymphoid hyperplasia (PNLH) compared with other lymphoid proliferations of the lung. Six cases of PNLH, 9 cases of low-grade B-cell lymphoma of the bronchus-associated lymphoid tissue (BALT), 8 cases of intraparenchymal lymph nodes, 8 cases of either primary or secondary follicular bronchiolitis, and 4 cases of lymphocytic interstitial pneumonitis were stained by immunohistochemical analysis for IgG4 and IgG. The mean number of IgG4-positive and IgG-positive plasma cells and the IgG4/IgG ratio were determined from a manual count of images from 3 separate high-power fields (hpf) of areas showing the highest numbers of stained cells, respectively.

Subcutaneous Panniculitis-like T-cell lymphoma in two pediatric patients: an HIV-positive adolescent and a 4-month-old infant.

Subcutaneous Panniculitis-like T-cell lymphoma (SPTCL) is a rare subtype of childhood non-Hodgkin lymphoma. Subcutaneous Panniculitis-like T-cell lymphoma has an aggressive variant associated with the hemophagocytic syndrome (HPS). Patients without HPS show resolution of the disease with prednisone or immunosuppressive therapy unlike other T-cell lymphomas.

Adult leukemic synovitis is associated with leukemia of monocytic differentiation.

Background: Leukemic synovitis is a rare complication of adult myeloid leukemias characterized by joint pain and swelling. It is important to recognize this diagnostic challenge as it may be the initial manifestation of leukemia or of relapse.

Methods: A retrospective search of patient files from 2 teaching hospitals identified 4 adult patients who presented with large joint arthritis and concurrent or subsequent leukemic synovitis.