Nonlymphoid hematopoietic malignant disease of the lymph nodes

The extension of myeloproliferative malignant tumors to lymph nodes was studied in seven excision biopsies and 27 autopsies in which lymph nodes were obtained from all nodal regions. We observed the proliferation of poorly, partially, and well differentiated neoplastic cells with a predominance of immature cells of the granulocytic series and fewer cells of the erythroid and megakaryocytic cells lines. Disturbances of the lymph node architecture consisted of invasion by abnormal cells of the trabecular stroma, disrupting the reticulin mesh and extending toward the pericapsular area. In the lymph node a loose network of thin and thick fibers replaced the original framework. Generalized lymph node involvement at autopsy showed preservation of the architecture, both in cases with total replacement of the lymphoid population by abnormal cells and in cases with involvement by single cells or small groups of cells. Partial involvement occurred chiefly in the medullary zone, probably the result of hematogenous dissemination from the vascular plexus in medullary cords. Further abnormal cell development was linked to trabecular infiltration. The extensive involvement seen at autopsy took place by lymphatic dissemination. In lymph nodes studied at autopsy an abnormal immunoblastic reaction was observed. At first these abnormal cells were suspected of representing the myeloproliferative malignant disease, but the application of special staining techniques revealed their polyclonal cytoplasmic immunoglobulins. The chloroacetate esterase stain and the immunohistochemical stains for muramidase and hemoglobulin were especially useful in demonstrating that myeloproliferative diseases develop in the environment found in lymph nodes.