Ukihide Tateishi

Immunohistochemical and gene rearrangement studies of central nervous system lymphomatoid granulomatosis

Lymphomatoid granulomatosis (LYG) is a rare multisystem disorder with characteristic angiocentric lymphoproliferative features, most frequently involving the lung, skin, and rarely the CNS. LYG has been classified into three subtypes based on the relative proportions of atypical and inflammatory infiltrating cells. Most systemic LYGs have been shown to be EBV‐associated, T‐cell rich, B‐cell proliferative disorders. Here, we present four cases of LYG arising from the CNS and have analyzed them by immunohistochemistry to assess the phenotype of the infiltrate, and by PCR‐SSCP (single‐strand conformation polymorphism) analysis for immunoglobulin heavy chain (IgH) and T‐cell receptor (TcR) γ gene rearrangements. Three cases revealed perivascular infiltration of T‐cell dominant lymphoid cells, two cases showed monoclonal TcRγ gene rearrangement, while the remaining case had a B‐cell immunophenotype and monoclonal IgH gene rearrangement with EBV genome expression. This is the first report of a gene rearrangement study on CNS‐LYG. We confirm that some cases of CNS‐LYG are derived from T‐cell monoclonal lymphoproliferative disease, although this disease should be classified as a borderline malignancy and should be separated from overt malignant lymphoma of CNS.

CNS lymphomatoid granulomatosis with lymph node and bone marrow involvements

Lymphomatoid granulomatosis (LYG) in the CNS is an uncommon lymphoproliferative disease with characteristic angiocentric lymphoreticular proliferative and granulomatous lesions exhibiting low‐grade malignant potential. Here we report a rare case of CNS‐LYG, which disseminated to the lymph node and bone marrow. A 50‐year‐old man was diagnosed with CNS‐LYG based on brain biopsy showing perivascular infiltration of CD3‐positive small T‐lymphocytes without overt nuclear atypism. Eight months after the initial neurological symptoms, inguinal lymph node swelling was found and histopathologically diagnosed as peripheral T‐cell lymphoma. TCRγ‐gene rearrangement study using both paraffin‐embedded specimens of brain and inguinal lymph node demonstrated an identical clonal band. Considering the clinical course, we concluded lymph node involvement of CNS‐LYG, suggesting the malignant potential of CNS‐LYG.

High-resolution CT findings of macrophage activation syndrome: a case report

Abstract Macrophage activation syndrome (MAS) is a rare disorder characterised by benign, reactive, excessive, well-differentiated macrophage proliferation, secondary to an immune dysregulation in response to some triggering agents such as viral infection. We report a 3-year-old girl with MAS and pulmonary involvement. This is the first radiographic description of MAS on high-resolution CT.