Atlas for the Diagnosis of Tumors in the Dog and Cat

Anita R. Kiehl, Maron Brown Calderwood Mays

• Publisher: Wiley-Blackwell
• Year: 2016
• Print ISBN:
  9781119051213
• eBook ISBN:
  9781119050797
• Edition: 1
• Topic: Medicine
• Subtopic: Veterinary Medicine

Atlas for the Diagnosis of Tumors in the Dog and Cat is a diagnostic tool for determining if samples are abnormal and defining the cause of the abnormality, with 386 clinical images depicting normal and abnormal results.

• Offers a brief overview of the methods used to produce a diagnosis and prognosis from a biopsy tissue sample
• Pairs photographs of biopsy samples with photomicrographs of cells obtained via fine needle aspirate
• Includes a useful chapter covering sample handling, staining, and shipping

 

PART I
Overview of the Diagnostic Process

1
Overview of Grading and Staging

Identification of the process

Tumor is a word of Latin derivation meaning a swelling or protruberance—a “mass.” In its broadest sense it includes masses formed by cellular inflammatory infiltrates, controlled proliferations of hyperplastic cells, and uncontrolled proliferations of neoplastic cells (cancer). Controlled proliferations of cells have a recognizable structure, may perform their usual physiologic function, do not invade local tissues, and suffer senescence and programmed cell death (apoptosis). Uncontrolled proliferations may contain cells of variable structure, may be functional or nonfunctional, may invade local tissues or cause local tissue necrosis by their increasing bulk, replicate in a disorderly manner, and do not suffer programmed cell death.

The path to successful treatment of a tumor begins with recognition of the lesion on a gross level, usually by the caretaker of a dog or cat, sometimes by a groomer, or often during a physical exam by a veterinarian. The next step is assignment of the pathological process into a category of inflammation, hyperplasia, or neoplasia, or some combination of these categories. This can be accomplished at the point of care by aspirating the lesion with a needle and examining the individual cells. In the following chapters this will be called fine needle aspiration (FNA). With some tumors, especially papillomas, impression or scraping of the lesion can yield diagnostic cells, but generally this is not the ideal method of collection, as surface contamination can make evaluation difficult. All cytologic samples are stained with Wright‐Giemsa (W‐G) stain unless otherwise indicated.

Figure 1.1 shows an apocrine gland adenoma FNA. This cluster of small epithelial cells is suggestive of a proliferation of basaloid epithelial cells or the ductular epithelium of an apocrine gland. The cell nuclei are small and regular, and there is scant inflammation, as shown by the neutrophil in this field.

Figure 1.1 Apocrine gland adenoma FNA. 50x.

When FNA of a mass reveals a population of proliferating cells, indicating the lesion is not merely an influx of inflammatory cells that can be relieved by medical means, biopsy allows histopathological evaluation of the affected tissue, showing the architectural arrangement of the cells and allowing for a more definitive diagnosis. This is the point where a hyperplastic growth is distinguished from a neoplastic growth based on how the cells are structurally arranged. FNA cannot evaluate architectural arrangement accurately, because the cells are usually stripped of their association by the process of aspiration. The decision to take an incisional biopsy that removes a portion of the mass, or an excisional biopsy that removes all of the mass, should be based on factors such as the tumor type suggested by the FNA, the size of the lesion, the location of the lesion, the stage of the disease, and other parameters such as the overall health of the patient and wishes of the owner. Ultimately the decision rests on the clinical judgment of the surgeon. All biopsies shown in the following pages are stained with hematoxalin and eosin (H&E), unless otherwise indicated.

Figure 1.2 is a biopsy showing the architecture of the gland aspirated in Figure 1.1. There are double rows of small epithelial cells proliferating in a manner that does not invade into the adjacent stroma, indicating that this is a benign apocrine gland tumor referred to as an apocrine ductular adenoma.

Figure 1.2 Apocrine gland ductular adenoma biopsy. 40x.

FNA can sometimes identify cells that are so clearly abnormal, either by morphology or cell density, that neoplasia can be diagnosed on a presumptive basis.

Figure 1.3 shows a transitional cell carcinoma FNA. An adult female mixed breed dog was presented for hematuria and dysuria. A tentative diagnosis of cystitis was made based on clinical signs, and cystocentesis was performed to collect urine for routine urinalysis and sedimentation. Cytologic exam revealed many clusters of large epithelioid cells with marked anisokaryosis (variation in nuclear size) and basophilic cytoplasm. There were scattered neutrophils, erythrocytes, and cellular debris. No infectious agents were seen. A preliminary diagnosis of neoplasia, probable transitional cell carcinoma, was made. Treatment for infectious cystitis, based just on clinical signs, would prove useless and would delay the true diagnosis. If neoplasia is suspected on presentation, catheterization would be the preferable method of collect...

Table of contents

• Cover
• Title Page
• Table of Contents
• Preface
• Acknowledgments
• PART I: Overview of the Diagnostic Process
• PART II: Case Studies
• Index
• End User License Agreement