Proliferative disorders in LN-ras2 reconstituted mice. (A) LK8 spleen section. Normal splenic architecture, follicular organization of the lymphoid cells, marginal zones, and red pulp composed of erythroid cells are shown. (B) Nr9 spleen section. The splenic architecture is disrupted by darkly stained hematopoietic cells (arrow). (C) Nr18 spleen section. Large foci of myelomonocytic cells that obliterate the normal splenic architecture (light staining) are shown. (D) Nr17 spleen section. Sheets of abnormal mast cells (light staining) that have disrupted the normal splenic architecture are shown. (E) LK8 spleen cells. Normal splenocytes, large and small lymphocytes, myeloid cells, and erythroid progenitor cells are shown. (F) Nr9 spleen cells. Abundant erythroid progenitors (arrows) are shown. (G) Nr16 spleen cells. Increased numbers of large monocytes (X) and myeloid cells (arrow) are shown. (H) Nr17 spleen cells. Darkly granulated mast cells (X) and increased numbers of erythroid progenitors (arrows) are shown. (I) LK8 blood. Normal erythrocytes and a neutrophilic granulocyte are shown. (J) Nr9 blood. Polychromatic and spiculated erythrocytes are demonstrated. (K) Nr18 blood. Two abnormal myelomonocytic cells are shown. (L) Blood from Nr17. Aberrant erythrocytes are shown. Histologic sections (A through D) were stained with hematoxylin and eosin (original magnification ×50). Cytospun preparations (E through H) and blood smears (I through L) were stained with May-Grunwald and Giemsa (original magnification ×500).