Objective: To understand the clinic opatholgic changes of midline malignant histiocytosis (MMH), and to explain the source of atypical lymphoid cells (ALC) of MMH, so as to search after the relation between MMH and malignant lymphoma.
Method: Histopathologic section of 39 cases of MMH were taken HE staining and the histopathologic changes were obsered under microscope. The immunohistochemical staining was also used to examine the immunophenotype of ALC.
Result: 1. Pathologic changes of MMH: coaglation necrosis and mixed inflammatory cells infiltration, with epithelial infiltration which distributed around the center of blood vessel were their characteristics. 2. Immunohistochemical staining result: 28 in 39 cases of MMH (71.8%) expressed the immunophenvtype of T-cell; among them 13 (33.3%) were finded both positive reaction to CD3 and CD57 antigens with ALCs at the same time.
Conclusion: According to immunophenotypic studies, most ALCs came from proliferation and infiltration of atypical T cell. ALCs of MMH expressed not only T-cell markers (CD3), but also NK-associated antigen (CD57). MMH was a mucosa related peripheral T/NK cell lymphoma originally.