SINUSOIDAL MICROVILLOUS LARGE-CELL LYMPHO MA - A CASE-REPORT

Microvillous non-hodgkin lymphomas are large cell malignant lymphomas with a sinus growth pattern and the presence of cytoplasmic processes detected by electron microscopy. Microvillous non-hodgkin lymphomas ap pear to be of B cell lineage. Neoplasms considered in the differential diagnosis include anaplastic large cell Ki-1 lymphomas, malignant his tiocytosis and metastatic carcinoma or malignant melanoma. A panel of markers are usually sufficient to recognize all of these neoplasms exc ept microvillous lymphomas.We report a case of microvillous non-hodgki n lymphoma characterized by a histologic pattern mimicking those of an aplastic large cell Ki-1 lymphoma. However, immunohistochemistry study failed to demonstrate presence of activation antigen such as Ki-1, EM A, interleukin 2 receptor. Ultrastructural study showed that neoplasti c cells exhibited filliform cytoplasmic processes. This report raise t he possibility of an overlap between microvillous non-hodgkin lymphoma s and anaplastic large cell Ki-1 lymphomas of B-cell lineage. It must be emphasized that, initially, these two kinds of lymphomas were defin ed with different morphologic technologies.