Mary Jo Burkhard, DVM, PhD, DACVP

The first part of this session will discuss increased or atypical WBC morphology and describe clues to determine whether the process is leukemic or reactive in origin.

Mycobacteria do not stain with routine cytologic stains and can be difficult to visualize. However, careful examination of the cells and background material reveals the presence of distinctive negatively stained thin rod present both intra- and extracellularly.

Small lymphocytes are smaller in size than a neutrophil and have a round nuclei that takes up the majority of the cell. The nuclei contain densely aggregated chromatin forming large chromocenters (condensed chromatin).

Fine needle aspiration (FNA) cytology is an excellent adjunctive tool for evaluating internal organs. It is often diagnostic, requires little specialized equipment, and can rapidly provide useful information.

Normally, only a small amount (milliliters) of fluid are present in the thorax and abdomen. Effusions, defined as an accumulation of fluid in one or more body cavities result from multiple causes including increased hydrostatic pressure, decreased oncotic pressure, increased vascular permeability, decreased lymphatic drainage, infection, neoplastic infiltration, or rupture of organs or structures within the cavity.

Hemotropic parasites are often associated with hemolytic anemia.

Cytolopathology: the laboratory and microscopic evaluation of cells and fluids. Sources of cells include tissue aspirates, imprints, scrapings, body fluids, or lavage fluids.

Round cell tumors are commonly detected as cutaneous or subcutaneous masses. However, the majority of these tumors also appear in other locations.

Cytology is useful for establishing a diagnosis or can narrow the list of differentials for effusions, masses, lymphadenopathy, or organomegaly.

Inflammatory lesions can occur due to infectious or non-infectious causes. Compared to tissue cells, inflammatory cells are readily collected by aspirates and scrapings.

Normally, only a small amount (milliliters) of fluid are present in the thorax and abdomen.

Mycobacteria do not stain with routine cytologic stains and can be difficult to visualize.

Fine needle aspiration (FNA) cytology is an excellent adjunctive tool for evaluating internal organs.

Small lymphocytes are smaller in size than a neutrophil and have a round nuclei that takes up the majority of the cell.

Leukemia: The presence of neoplastic cells in circulation.

Anisocytosis: Variation in cell size, can be either small or large.

Mycobacteria do not stain with routine cytologic stains and can be difficult to visualize.

Round cell tumors are commonly detected as cutaneous or subcutaneous masses.

Inflammatory lesions can occur due to infectious or non-infectious causes.

As the primary cell type present in lymphoid organs is lymphocytes, the first part of this handout will describe the morphologic features of lymphocytes and then briefly describe other methods to assess lymphocytes.

Normally, only a small amount (milliliters) of fluid are present in the thorax and abdomen.

Cytolopathology: the laboratory and microscopic evaluation of cells and fluids.