Veterinary Pathology Publications and Papers Veterinary Pathology

10-2000

Gastrointestinal Endoscopic Exfoliative Cytology:Techniques and Clinical ApplicationAlbert E. JergensIowa State University, ajergens@iastate.edu

Claire B. AndreasenIowa State University, candreas@iastate.edu

Kristina G. MilesIowa State University, kmiles@iastate.edu

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Gastrointestinal Endoscopic Exfoliative Cytology: Techniques andClinical Application

AbstractCytologic examination of exfoliative specimens obtained during endoscopy is a useful and reliable adjunct tomucosal biopsy for the diagnosis of gastrointestinal (GI) tract diseases in dogs and cats. Clinical advantages ofendoscopic cytology include simplicity, rapidity of diagnosis and minimal invasiveness. Cytologic smears aregraded on the basis of objective criteria, including the presence and number of inflammatory, atypical, andepithelial cells as well as the presence of bacteria, hemorrhage, debris/ingesta, and mucus. There is highcorrelation between results obtained from endoscopic cytology and histologic examination, and discordantresults are infrequent. Brush cytology is useful in detecting mucosal inflammation, whereas touch cytology ismore likely to detect acute purulent and erosive mucosal lesions. Alimentary lymphoma my be readilydiagnosed using either technique. This article provides an overview of how cytologic smears are prepared andevaluates their diagnostic accuracy.

KeywordsVeterinary Clinical Sciences, gastrointestinal tract, endoscopic cytology

DisciplinesSmall or Companion Animal Medicine | Veterinary Medicine | Veterinary Pathology and Pathobiology

CommentsThis article is from Compendium on Continuing Education for the Practicing Veterinarian 22 (2000): 941-952.Posted with permission.

This article is available at Iowa State University Digital Repository: http://lib.dr.iastate.edu/vpath_pubs/60

Vol. 22, No. 10 October 2000

Refereed Peer Review

FOCAL POINT

KEY FACTS

�Endoscopic exfoliative cytology is a useful and reliable adjunct tomucosal biopsy for the diagnosisof gastrointestinal (GI) tractdiseases in dogs and cats.

GastrointestinalEndoscopic ExfoliativeCytology: Techniquesand Clinical ApplicationIowa State University

Albert E. Jergens, DVM, MSClaire B. Andreasen, DVM, PhDKristina G. Miles, DVM, MS

ABSTRACT: Cytologic examination of exfoliative specimens obtained during endoscopy is auseful and reliable adjunct to mucosal biopsy for the diagnosis of gastrointestinal (GI) tractdiseases in dogs and cats. Clinical advantages of endoscopic cytology include simplicity, ra-pidity of diagnosis, and minimal invasiveness. Cytologic smears are graded on the basis of ob-jective criteria, including the presence and number of inflammatory, atypical, and epithelialcells as well as the presence of bacteria, hemorrhage, debris/ingesta, and mucus. There ishigh correlation between results obtained from endoscopic cytology and histologic examina-tion, and discordant results are infrequent. Brush cytology is useful in detecting mucosal in-flammation, whereas touch cytology is more likely to detect acute purulent and erosive mu-cosal lesions. Alimentary lymphoma may be readily diagnosed using either technique. Thisarticle provides an overview of how cytologic smears are prepared and evaluates their diag-nostic accuracy.

Advances in endoscopy have revolutionized the detection of gastrointesti-nal (GI) tract diseases in companion animals.1–5 Histologic examinationof forceps biopsies is used to establish a definitive diagnosis of mucosal

disease. Endoscopic exfoliative cytology is a useful adjunct to biopsy for detec-tion of GI tract diseases in humans,6–9 and the results correlate highly with histo-logic observations in dogs and cats.10,11 However, little data12 exist that describethe findings made by using this diagnostic technique. This article reviews ourexperience using endoscopic exfoliative cytology in the diagnosis of canine andfeline GI tract diseases.

COLLECTION METHODS AND SMEAR PREPARATIONNumerous mucosal disorders are amenable to diagnosis by endoscopic cytology

(see Gastrointestinal Tract Disorders Amenable to Endoscopic Cytology). Cyto-logic specimens should be obtained after mucosal biopsy because this technique

CE

V

� Exfoliative cytology can be performed easily along with mucosal biopsy duringendoscopic examination of the GI tract.

� Cytologic smears may be madeby the brush or touch techniqueand are graded by objectivecriteria.

� Endoscopic cytologic specimenshave a high diagnostic accuracycompared with histologicspecimens.

� Endoscopic cytology of thecanine and feline GI tracts aids in differentiation of normalmucosa from mucosa infiltratedby inflammatory cells orneoplastic diseases.

© The North American Veterinary Community (NAVC) and Vetstreet, Inc. Reprinting or posting on an external website without permission from NAVC is a violation of copyright law.

has shown the highest diagnosticaccuracy for detecting GI tractdiseases in humans.13,14 Cytologicsmears may be prepared using thebrush or touch technique.

With the brush technique, asingle-use guarded cytology in-strument is passed through the ac-cessory channel of the endoscopeand advanced to the mucosa. Thebrush is extended beyond its pro-tective sheath and exfoliative spec-imens are obtained by rubbing thebrush vigorously on the mucosauntil slight hemorrhage occurs(Figure 1A). The brush is then re-tracted into its sheath and with-drawn from the endoscope. Thebrush is again extended from itssheath and rolled across a glassslide to make a cytologic smear(Figure 1B). The brush should becarefully rotated 360˚ while tra-versing the slide’s surface, therebyensuring maximum transfer of cel-lular material (Figure 1C).

The touch technique involvesthe transfer of a mucosal speci-men from the biopsy forceps to aglass slide using a hypodermic needle (Figures 2A and2B). Multiple cytologic imprints can be made by plac-ing a second slide on top of and at right angles to thefirst slide and applying light pressure (Figure 2C). Ex-cessive downward pressure and smearing should beavoided because this may result in cell rupture. Ideally,four slides (two slides using each cytologic technique)should be prepared for each organ being evaluated en-doscopically. Following smear preparation, slides shouldbe air-dried and stained with a Romanovsky-type stainfor evaluation (see Enhancing the Diagnostic Yield ofGastrointestinal Tract Endoscopic Exfoliative Cytology).

CRITERIA FOR CYTOLOGIC EXAMINATIONObjective criteria for evaluation of GI tract endo-

scopic exfoliative cytologic specimens have been de-scribed and validated.12 Briefly, a grading system basedon several categories is used (Table I). Cytologic gradesof 2 or lower for cellularity categories are generally notdiagnostically significant. A minimum of 10 micro-scopic fields should be evaluated on each slide before acytologic diagnosis is made. This grading system facili-tates consistent and rapid evaluation of cytologic prepa-rations (Figure 3).

PROSPECTIVE EVALUATIONOF ENDOSCOPIC CYTOLOGY

Over the past 3 years, endo-scopic exfoliative cytology hasbeen extensively performed inour institution as an adjunct tomucosal biopsy for diagnosingchronic GI tract disease in dogsand cats. We have reported pre-liminary observations in 85 dogsand 23 cats in which cytologicfindings were compared with his-tologic observations.12 These datahave been expanded to includean additional 37 canine and 12feline cases; the histologic find-ings and diagnostic accuracy15 ofthe cytologic findings of thisstudy are summarized in Tables IIand III, respectively. Endoscopiccytology remains an extremelyuseful diagnostic technique thataids in the differentiation of nor-mal mucosa from mucosa infil-trated by inflammatory cells orneoplastic disease (Table II). Sim-ilarly, the correlation between re-sults obtained on cytologic versushistologic examination is high

(Table III) and compares favorably with results fromsimilar studies of humans with gastric mucosal dis-ease.16–18

Endoscopic cytology is extremely useful in detectingmucosal inflammation of varied causes. Mucosal infil-trates of lymphocytes and plasma cells were observedcommonly with inflammatory bowel diseases, small in-testinal bacterial overgrowth, intestinal lymphangiecta-sia, and Physaloptera species infection of the stomachand duodenum19 (Figure 4). Gastric spirillar organismswere readily detectable by brush cytology in 57% of alldogs and cats but were infrequently observed in histo-logic specimens. The high diagnostic sensitivity of thebrush technique in detecting gastric spirillar organismsin dogs and cats in our study was consistent with re-sults of other studies.20,21 Alimentary neoplasia (espe-cially lymphoma) may be diagnosed by either brush ortouch cytologic techniques; however, detection appearsdependent on the extent of cellular infiltration and mu-cosal disruption (e.g., ulceration, erosion), which mayaid exfoliation. Some lymphomas may be difficult todifferentiate from severe lymphocytic-plasmacytic (LP)enteritis when larger lymphocytes are present (Figure5). Gastric adenocarcinomas may evade cytologic de-

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� Esophagus—Esophagitis—Stricturea

—Neoplasia� Stomach

—Chronic gastritis• Inflammatory bowel disease-associated• Nematode-associated

—Ulcer/erosions—Neoplasia/polyps

� Small intestine—Fungal enteritis—Neoplasia—Inflammatory bowel disease; small

intestinal bacterial overgrowth� Colon

—Inflammatory bowel disease—Fungal colitis—Neoplasia—Inflammatory polyps

aStricture associated with malignant neoplasia oractive esophagitis.

Gastrointestinal Tract Disorders Amenable to Endoscopic Cytology

tection because of their multifocal and deeply infiltra-tive nature and the surrounding fibrosis that preventsexfoliation of representative cells (Figure 6).22

Discordant results be-tween cytologic and histo-logic findings were un-commonly observed. Thepercentages of false-positiveresults (11 of 314 pairedcytologic specimens; 3.5%) and false-negative (24of 314 paired cytologicspecimens; 7.6%) results inour study were low andcomparable to those of sim-ilar studies in humans.8,18,23

The reasons for discordanceare diverse but include dif-ficulty in differentiatingmild inflammatory lesionsfrom normal; technicalcomplications caused bypoor orientation of tissueduring embedding for his-tologic examination or in-advertent sampling of amucosal lymphoid aggre-gate; the presence of focal,fibrotic, or deeply infiltra-tive mucosal lesions; andthe presence of functionalGI tract disease.24

CLINICALAPPLICATIONSCase 1: ChronicPostprandial Vomiting in a DogClinical Synopsis

A 13-year-old neuteredpoodle was referred be-cause of 3 weeks of spo-radic vomiting episodesthat generally occurred 8to 12 hours after eating.The vomitus frequentlycontained partially digest-ed food and bile. Appetiteand activity were normal,and no diarrhea or weightloss was reported. Physicalexamination revealed analert, mildly obese dog.

Initial diagnostic tests (i.e., complete blood count, serumbiochemical profile, urinalysis, direct/indirect fecal exam-inations, survey abdominal radiography) showed no ab-

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Figure 1B

Figure 1C

Figure 1—Brush cytologic technique. (A) Theguarded cytology brush is extended beyond itsprotective sheath and has abraded the gastricmucosa. (B) The exfoliated material is streakedacross a glass slide to make a monolayer for cy-tologic examination. (C) To prepare the slide,the brush should be rotated 360° to maximizetransfer of cellular material.

Figure 1A

Figure 2B

Figure 2C

Figure 2—Touch cytologic technique. (A) Us-ing forceps, a biopsy sample is obtained fromthe gastric mucosa. (B) The mucosal specimenis transferred from the forceps using a hypo-dermic needle. (C) A mucosal specimen isplaced between two glass slides to make cyto-logic imprints.

Figure 2A

normalities. An upper GI series using liquid bariumdemonstrated partial pyloric outflow obstruction. UpperGI tract endoscopy (i.e., gastroscopy, duodenoscopy) wasperformed.

Endoscopic/Cytologic Observations

Endoscopic examination revealedno abnormalities of the proximalstomach and gastric body. Withinthe antrum, a large polypoid masswas observed adjacent to the py-lorus obstructing the pyloric open-ing. Brush cytologic specimens ofthe mass consisted of a uniformpopulation of benign gastric epithe-lial cells with no evidence of malig-nancy (Figure 7). A cytologic diag-nosis of epithelial hyperplasia wasmade. Owner consent was given forgastrotomy and the mass was suc-cessfully removed.

AssessmentEndoscopic cytology allowed a

rapid intraoperative tentative diag-nosis of epithelial hyperplasia. Theclient had requested humane eu-thanasia for her dog if gastric malig-nancy were detected; therefore, thisfacilitated a therapeutic decision ofpolypectomy. Histologic examina-

tion of the excised mass confirmed the cy-tologic findings (adenomatous polyp). Fol-lowing surgery, vomiting episodes ceasedand the dog was discharged.

Case 2: Episodic Regurgitation in a CatClinical Synopsis

A 5-year-old neutered domestic shorthaircat was admitted for episodic regurgitationof 2 weeks’ duration. A moderately de-creased appetite and weight loss (1 kg) werealso reported by the owner. Physical exami-nation revealed a thin, active cat with afever (104˚F). Initial laboratory tests (i.e.,complete blood count, serum biochemicalprofile, urinalysis, feline leukemia virus[FeLV] ELISA, cervical/thoracic radiogra-phy) revealed mild anemia (hematocrit,28%), a positive FeLV test, and lateral dis-placement of the midcervical trachea. Ultra-

sound evaluation of the cervical region and an esopha-gram confirmed the presence of a periesophageal oresophageal wall mass. Esophagoscopy was performed thefollowing day.

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� Excellent mucosal biopsy technique should be used to maximizediagnostic yield25,26 and corroborate cytologic observations.

� Cytologic specimens should be obtained after mucosal biopsy. � Cytologic specimens should be obtained regardless of the

endoscopic appearance of the mucosa.� The brush and touch techniques complement each other and should

both be performed. � When making touch impressions, excessive pressure should be

avoided because it may result in cell rupture. Overzealous brushingproduces hemorrhage, confounding leukocyte interpretation.

� Objective grading criteria should be used when assessinggastrointestinal tract cytologic specimens.

� Appropriate patient history and endoscopic observations should becommunicated to the cytopathologist(s) to facilitate diagnosticinterpretation.

Enhancing the Diagnostic Yield of Gastrointestinal Tract Endoscopic Exfoliative Cytology

TABLE IGastrointestinal Cytologic Grading Criteria

Category Grading Scheme

Inflammatory cells Scored 0–7, which corresponds to Neutrophils, lymphocytes, plasma 0–7 cells/50× oil-immersion field; cells, eosinophils, macrophages if >7 cells/field, a grade of 7 is assigned

Atypical cellsCells with altered nuclear/cytoplasmic characteristics

Epithelial cells Grade corresponds to number of Evaluated as cell clusters clusters/10× field

Bacterial flora Scored 0–7:Gastric spirillar organisms, oral flora, 0 = noneenteric rods and cocci 1–2 = slight

3–4 = moderateHemorrhage 5–7 = markedPresence of peripheral blood

Debris/ingestaPlant material or pigmented particulate matter

MucusDiffuse basophilic mucinous material

Endoscopic/Cytologic ObservationsA large, smooth-surfaced, eroded mass occluding the

proximal esophageal lumen was seen by esophagoscopy.The mass did not arise from the mucosa but projectedinto the lumen as a periesophageal structure. Cytologicspecimens were obtained by both endoscopy and fine-needle aspiration of the mass under ultrasound guid-ance. Examination of cytologic preparations showed ahomogenous population of large immature lympho-cytes consistent with a diagnosis of lymphosarcoma(Figure 8). Histologic specimens of esophageal mucosawere nondiagnostic.

AssessmentClinical observations and diagnostic testing were con-

sistent with a diagnosis of primary esophageal disease. Ex-

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Figure 3A

Figure 3C

Figure 3D

foliative cytology allowed a diagnosis of periesophagealneoplasia to be made despite the absence of histologicconfirmation of lymphosarcoma. This case emphasizesthe adjunctive role of GI tract endoscopy in the diagnosisof alimentary neoplasia. The cat was treated with multi-ple-drug chemotherapy for lymphosarcoma, leading torapid remission of clinical signs and radiographic lesionswithin 2 weeks. Clinical signs of regurgitation returned 9months later, prompting euthanasia.

Case 3: Anorexia and Weight Loss in a CatClinical Synopsis

A 12-year-old neutered domestic shorthair cat with a1-year history of intermittent anorexia, vomiting, andweight loss was evaluated. Vomiting episodes were typi-cally cyclic (occurring over 48 hours) and would then re-solve. Weight loss exceeding 8 lb was confirmed. Onphysical examination, the cat was alert and active, but re-duced lean muscle mass was noted. Over the previous 12months, a variety of diagnostic tests had been performedin a step-wise fashion, including routine hematology, uri-nalysis, multiple serum total thyroxine tests, abdominalradiography, and serology for FeLV and feline immuno-deficiency virus. Prophylactic dewormings and dietarytrials resulted in little clinical improvement. Upper GItract endoscopy was then performed.

Figure 3E

Figure 3B

Figure 3—(A) Brush cytolo-gy of the colon showing twoclusters of uniform epithelialcells with round to oval nu-clei and confluent basophiliccytoplasm. (B) Touch cytol-ogy of the colon showing se-vere suppurative inflamma-tion and diffuse bacterialflora. (C) Brush cytology ofthe stomach showing gastricspirillar organisms that areembedded within superficialmucus. (D) Touch cytologyof the colon showing a clus-ter of malignant lympho-cytes containing large prom-inent nuclei and multiplenucleoli. (E) Brush cytologyof the colon showing hem-orrhage (grade 4–5) with asingle cluster of epithelialcells. Hemorrhage may oc-cur in association with tissuefriability or iatrogenic trau-ma.

Endoscopic/Cytologic ObservationsEndoscopic examination of the esophagus and stomach

was unremarkable. Visualizationof the proximal duodenum re-vealed marked mucosal granulari-ty and friability. Multifocal erosivelesions were apparent throughoutmost of the distal duodenum andjejunum. Small intestinal brushand touch cytologic specimenswere similar with moderate-to-se-vere LP inflammation (Figure 9).Histologic examination of muco-sal biopsy specimens confirmedthe cytologic finding of LP enteri-tis (Figure 10). Gastric mucosalspecimens were histologically nor-mal.

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TABLE IIIDiagnostic Accuracy of Cytologic Specimens Obtained During Endoscopy15

Sampling Site

Valuea Stomach Small Intestine Colon

Sensitivity (%) 73 92 86 Specificity (%) 97 80 100 Positive predictive value (%) 91 92 100 Negative predictive value (%) 89 80 75 aDiagnostic indices calculated using standard formulas.

TABLE IIDistribution of Histologic Findings in Which Endoscopic Cytology Was Also Performed12

Biopsy Site

Histologic Finding Stomach Small Intestine Colon

Normal 88 31 12 Spirochetes 3 NA NA Inflammation

Lymphocytic-plasmacytic 25 91a 18 Eosinophilic 4 3 NA Mixedb 8 3 8

Neoplasia Lymphosarcoma 3 4 2 Adenocarcinoma 1 NA NA

Atrophy/fibrosis 7 3 NA Total cytologiesc 139 135 40

NA = Not applicable.aIncludes inflammation seen with lymphangiectasia, bacterial overgrowth, and Physaloptera species infection.bDenotes suppurative, eosinophilic, and/or granulomatous inflammation.cPaired brush and touch cytologic specimens.

AssessmentSevere LP enteritis was readily detectable using endo-

scopic exfoliative cytology. Themagnitude of intestinal inflamma-tion was marked as evidenced by ahigh (5 of 6) cytologic gradingscore, numerous sites of lympho-cytic infiltration within the epithe-lium, and observation of largegranular lymphocytes in brushspecimens. Treatment of this catincluded feeding a commerciallyprepared hypoallergenic diet andadministration of prednisone andmetronidazole at immunomodu-lating doses. Remission of signsoccurred over 4 months, and drugadministration was discontinued.

Figure 4—Brush cytology of the small intestineshowing mild lymphocytic-plasmacytic inflamma-tion with clusters of lymphocytes (arrow) embed-ded within duodenal epithelium.

Case 4: ChronicIntermittent Vomiting in a DogClinical Synopsis

A 1-year-old spayedWhippet was referred forendoscopic evaluation ofchronic vomiting. Cyclicvomiting episodes overthe preceding 4 monthshad been nonresponsiveto dietary therapies andrepeated dewormings.Diagnostic evaluation(i.e., hematology, serumbiochemistries, urinaly-sis, fecal examinations,abdominal radiography)by the referring veteri-narian showed no abnor-mal results. Upper GItract endoscopy was per-formed.

Endoscopic/Cytologic Observations

Both esophagoscopyand gastroscopy failed toshow mucosal abnormal-ities in this dog. In theproximal duodenum,several nematodes wereobserved along the mu-cosa, which also con-tained multifocal attach-ment sites. Extraction oftwo parasites confirmedthem to be nongravid fe-male Physaloptera species.Mucosal specimens ob-tained for histologic/cy-tologic evaluation con-firmed the presence ofLP enteritis (Figure 11).Gastric biopsies werenormal histologically.

AssessmentBrush cytology is extremely useful in detecting mucosal inflamma-

tion of various causes (Table II). Our experiences indicate that Phys-aloptera species infection is frequently accompanied by intense mucosalinfiltrates of lymphoid cells that contribute to clinical signs.19 Treatment

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Figure 5A

Figure 5B

Figure 5—Cytologic discordance in small intesti-nal lymphoma. (A) Touch cytologic specimencontaining numerous large immature lympho-cytes (arrows) interpreted as lymphoma. (B) His-tologic section obtained by endoscopic forcepsbiopsy showing villus atrophy, edema, and dif-fuse lymphocytic-plasmacytic (LP) infiltration ofthe lamina propria. The initial histologic diagno-sis was severe LP enteritis. Repeat duodenal bi-opsy with histologic examination 7 days laterconfirmed the cytologic finding of lymphoma.

Figure 6B

Figure 6C

Figure 6—Cytologic discordance in gastric ade-nocarcinoma. Cytologic specimens obtainedfrom the periphery of gastric erosions and thegastric body were interpreted as suppurative in-flammation (A) and normal epithelial cells (B),respectively. (C) Histologic review of biopsyspecimens confirmed a diagnosis of gastric ade-nocarcinoma. Note the presence of isolatedsignet ring cells deep within the gastric mucosa(arrow).

Figure 6A

Figure 7—Brush cytology obtained from a py-loric mass. A uniform population of gastric epithelial cells with oval nuclei and confluentcytoplasm can be observed. The cytologic inter-pretation was epithelial hyperplasia.

of this dog with pyrantel(administered once) andmetronidazole (to reducemucosal cellular infil-trates) was curative.

Case 5: Tenesmusand IncreasedFrequency of Defecation in a DogClinical Synopsis

A 1-year-old spayedboxer was referred for en-doscopic evaluation ofcolonic disease. The ani-mal had been straining todefecate and had shownan increased frequency ofdefecation for over 3 weeks.The feces were generallywell formed but were en-cased by mucus. Physicalexamination, includingthorough digital exami-nation of the rectum, re-vealed no abnormalities.Initial diagnostic tests(i.e., hematology, serumbiochemistries, urinaly-sis, survey abdominal ra-diography, and multiplefecal analyses) were unre-markable. The adminis-tration of multiple an-thelmintic drugs also hadfailed to alleviate signs.Following preparationwith an oral lavage solu-tion, colonoscopy was per-formed.

Endoscopic/Cytologic ObservationsExcellent cleansing with the lavage solution allowed full visualiza-

tion of all mucosal surfaces. Most striking was the appearance of dis-crete nodules along the entire descending colonic mucosa, which wasconsistent with marked lymphoid hyperplasia. Similar, but fewer, le-sions accompanied by multifocal erosions were observed in the trans-verse colon. Brush cytologic specimens showed moderate LP infiltratesin all colonic regions (Figure 12). Moderate to severe LP colitis wasconfirmed histologically from examination of mucosal biopsy speci-mens.

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Figure 8—Brush cytology procured from a peri-esophageal mass. Numerous large immaturelymphocytes (arrows) with large nuclei and mul-tiple nucleoli can be observed. The cytologic in-terpretation was lymphoma.

Figure 11—Brush cytology of the proximal duo-denum. Lymphocytes (arrows) are clusteredaround and adjacent to intestinal epithelial cells.Cytologic interpretation was lymphocytic-plas-macytic inflammation.

Figure 10—Histologic section of intestinal mu-cosa with severe diffuse lymphocytic-plasmacytic(LP) infiltration of the lamina propria with villusblunting and dilation of the central lacteals. Thehistologic diagnosis was severe LP enteritis.

Figure 9A

Figure 9B

Figure 9—Brush cytology of the small intestine.(A) Clusters of small lymphocytes (arrow) are em-bedded within normal intestinal epithelial cells.(B) A mixed population of inflammatory cells,lymphocytes, and neutrophils (asterisks) can beseen with epithelial cells and a large granularleukocyte (arrow). The cytologic interpretationwas severe lymphocytic-plasmacytic inflammation.

AssessmentGastrointestinal tract endoscopic

cytology provided a reliable tenta-tive diagnosis while awaiting histo-logic review of biopsy specimens.Cytologic lesions were most pro-nounced in brush specimens,which is typical with mucosal in-flammation. Specific therapy forthis dog included dietary modifica-tion (low-residue diet) and drugtherapy (immunomodulating dosesof prednisone and metronidazole).The dog showed excellent responseto therapy and clinical signs re-gressed over 6 weeks. Drugs weregradually tapered, and the dog hasbeen maintained on diet alone.

SUMMARYIn conclusion, we believe that endoscopic cytology,

which is a simple technique, is useful in the diagnosis ofGI diseases in dogs and cats. The results of our prospec-tive study indicate that the combined brush and touchcytology with mucosal biopsy under direct endoscopic vi-sualization are useful in the diagnosis of GI inflammationand malignancy in a significant number of cases. We rec-ommend that endoscopic cytology be routinely used asan adjunctive diagnostic technique whenever mucosalbiopsy is performed.

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C Y T O L O G I C L E S I O N S � D I E T A R Y M O D I F I C A T I O N � D R U G T H E R A P Y

Figure 12—Brush cytology of the colon. Colonicepithelial cells and lymphocytes (arrows) are in-dicative of lymphocytic inflammation.

About the AuthorsDrs. Jergens and Miles are affiliated with the Department of Veterinary Clinical Sciences and Dr. Andreasen with the Depart-ment of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, Ames. Dr. Jergens is a Diplomate of theAmerican College of Veterinary Internal Medicine, Dr. Andreasen is a Diplomate of the American College of Veterinary Patholo-gists, and Dr. Miles is a Diplomate of the American College of Veterinary Radiology.

Small Animal/Exotics Compendium October 2000

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