Nucleoli Information and Courses from MediaLab, Inc.

Four blast cells are seen in this field. Notice the smooth chromatin pattern, nucleoli, high NC ratio and irregularly shaped nuclei. These blasts were observed in a spinal fluid sample from a patient with acute lymphocytic leukemia.

Blast cells may be seen in the spinal fluid when cell proliferation in acute leukemia or lymphoma spreads to the central nervous system. The arrows indicate the two blasts in this field. Notice the smooth chromatin pattern in the nucleus and prominent nucleoli in both cells. Notice that an Auer rod is present in the cytoplasm in the blast to the right. The Auer rod indicates that these blasts are myeloblasts rather than lymphoblasts. A segmented neutrophil and several red cells can also be seen.

Malignant cells that have broken away from tumors located in other areas of the body may be seen in spinal fluid. All of the cells in this field are tumor cells. The cells in this slide are characterized by an open, loose chromatin pattern, nucleoli and vacuoles. Notice that the vacuoles are present in both the nucleus and the cytoplasm. Vacuoles in the nucleus are an unusual finding even in tumor cells. Tumor cells are often found in clumps and may have more than one nucleus due to their erratic mitotic patterns. Malignant cells sometimes have an irregular nuclear shape. Bizarre granules may be found in malignant cells but are absent in mesothelial cells.

The next stage is the fully developed megakaryocyte. It typically shows nuclear divisions and abundant very granular cytoplasm. Megakaryocytes are the largest cell found in normal bone marrow and can range in size from 30-100 microns. The nuclear chromatin pattern is coarse. Nucleoli are absent.