Muscle biopsy using the muscle punch--removal technique, transport and evaluation ability

Histopathological striated muscle examination is one of the most important and sensitive tests in diagnosis of muscle and/or nerve diseases. Although muscle biopsy is a relatively easy procedure, it is not frequently performed in small animal practice conditions. Different biopsy techniques have been described in veterinary literature. Punch biopsy of striated muscle appears to be a less invasive and quicker method in comparison with traditional surgical excision technique. Additionally, punch biopsy provide good quality and adequate amount of muscle tissue for diagnostic histopathological evaluation. The aim of this study is to describe striated muscle punch biopsy technique and to encourage use of it under the conditions of small animal practice. The described biopsy method can be specially advantageous in screening of inherited muscle diseases in affected litters or even wider animal population.     

A modified biopsy technique to improve histopathological evaluation of avian skin

Skin biopsies are a viable diagnostic tool in avian dermatology, however, the thinness of avian skin makes it difficult to prevent rolling and contraction of skin biopsy specimens during collection and fixation. The difficulty orienting such rolled samples during processing ultimately interferes with the establishment of a histopathological diagnosis. We describe a modified skin biopsy procedure for obtaining avian skin biopsy specimens. In this technique nontranslucent self-adhesive tape (Scotch tape) was attached to skin biopsy sites before obtaining skin biopsies using a standard skin biopsy punch instrument. A total of 23 skin biopsy specimens were obtained: 15 from nonfeathered skin of 12 normal Hispaniolan parrots, 3 from feathered skin of 2 normal birds and 5 from feathered skin of 3 psittacines presented for pathologic feather-picking. All 23 skin specimens consistently adhered to the tape during the biopsy procedure. The specimens were fixed in 10% neutral phosphate-buffered formalin. During processing, no curling or rolling of specimens occurred, and all specimens could be easily orientated for correct trimming and subsequent histopathological evaluation. The tape technique did not produce any appreciable artefacts. Remnants of the tape were microscopically evident above the stratum corneum assuring that none of the stratum corneum was lost during processing. Obtaining avian skin biopsy specimens using this modified tape technique is easy and ensures flat fixation of the skin biopsy specimens, which later allows trimming at right angles, and through the longitudinal diameter of feather follicles for accurate histopathologic evaluation.     

Diagnostic algorithm to differentiate lymphoma from inflammation in feline small intestinal biopsy samples

Differentiating between inflammatory bowel disease (IBD) and small intestinal lymphoma in cats is often difficult, especially when only endoscopic biopsy specimens are available for evaluation. However, a correct diagnosis is imperative for proper treatment and prognosis. A retrospective study was performed using surgical and endoscopic intestinal biopsy specimens from 63 cats with a history of chronic diarrhea or vomiting or weight loss. A diagnosis of lymphoma or inflammation was based on microscopic examination of hematoxylin and eosin (HE)-stained sections alone, HE-stained sections plus results of immunohistochemical labeling (IHC) for CD3e and CD79a, and HE staining, immunophenotyping, and polymerase chain reaction (PCR) results for B and/or T cell clonality. In addition, various histomorphologic parameters were evaluated for significant differences between lymphoma and IBD using Fisher's exact test. The sensitivity and specificity of each parameter in the diagnosis of lymphoma were also determined. Results of Bayesian statistical analysis demonstrated that combining histologic evaluation of small intestinal biopsy specimens with immunophenotyping and analysis of clonality of lymphoid infiltrates results in more accurate differentiation of neoplastic versus inflammatory lymphocytes. Important histologic features that differentiated intestinal lymphoma from IBD included lymphoid infiltration of the intestinal wall beyond the mucosa, epitheliotropism (especially intraepithelial nests and plaques), heterogeneity, and nuclear size of lymphocytes. Based on the results of this study, a stepwise diagnostic algorithm that first uses histologic assessment, followed by immunophenotyping and then PCR to determine clonality of the lymphocytes, was developed to more accurately differentiate between intestinal lymphoma and IBD.     

Use of a dermal biopsy punch for removal of ectopic cilia in dogs: 19 cases

OBJECTIVE: To evaluate the use of a dermal biopsy punch for accurate and quick removal of ectopic cilia in dogs. ANIMALS STUDIED: This study reports the treatment of ectopic cilia detected in 12 dogs during the period from June 2002 to December 2004. Five cases were affected with ectopic cilia in the right eye, and five in the left eye, with two cases affected bilaterally. Nineteen ectopic cilia were detected in 12 dogs. PROCEDURE: The technique described in this study consists of using a 2-3-mm skin biopsy punch with the aid of an operating microscope. RESULTS: No recurrence was noted in any of the cases. The presurgical blepharospasm due to the presence of the cilia resolved as well as uneventful corneal healing of any associated corneal erosions or ulcers. CONCLUSIONS: This method offers a simple, practical alternative to the traditional scalpel procedure as described in the veterinary ophthalmic literature.     

Transperineal punch biopsy of the canine prostate gland

Transperineal punch biopsy using an obturator-canula assembly ('Tru-cut') was performed successfully under general anaesthesia in twenty-three dogs suspected of having prostatic disease. Diagnostic portions of tissue were obtained in all cases. One dog developed transient post-operative orchitis and scrotal oedema.     

Laparoscopic intestinal exploration and full-thickness intestinal biopsy in standing horses: a pilot study

OBJECTIVE: To assess a laparoscopic technique for equine intestinal biopsy. STUDY DESIGN: Experimental study. ANIMALS: Seven adult horses. METHODS: Food but not water was withheld for 36 hours before laparoscopy. In 3 horses (group A) standing, right laparoscopic access to different small intestinal segments was compared with ventral median celiotomy access. Inaccessible segments were identified at necropsy. In 4 horses (group B), the feasibility of obtaining full-thickness duodenal and cecal biopsies and any associated morbidity were evaluated. Biopsy specimens were collected during standing right laparoscopy using a 2-step procedure and intracorporeal suturing technique, and abdominal lavage was performed. Horses were monitored clinically and by abdominal fluid cytology and microbial culture, and repeat laparoscopy was performed on day 6. RESULTS: Standing right flank laparoscopy provided good observation of small intestinal segments and enabled manipulation of all but 15-20 cm of the duodenum and approximately 40 cm more ileum compared with ventral median celiotomy. Group B horses had no complications, no adhesions, and no bacterial growth from peritoneal fluid samples. None of the horses had signs of abdominal pain. CONCLUSION: A 2-stage intestinal biopsy technique performed during standing, right flank laparoscopy may be a safe alternative to exploratory celiotomy and biopsy in normal horses. CLINICAL RELEVANCE: Right flank laparoscopy allows biopsy of intestinal segments including duodenum and 50% more of the ileum than is accessible by ventral median celiotomy. This technique should be evaluated in clinical patients.     

Diagnostic accuracy of pre‐treatment biopsy for grading soft tissue sarcomas in dogs

Histologic grade is an important prognostic factor for both local recurrence and metastatic potential with canine soft tissue sarcoma (STS). Pre‐treatment biopsy with identification of tumour grade may aid in prognostication and determination of surgical margins necessary for local control. The purpose of this study was to evaluate the grading accuracy of various pre‐treatment biopsy techniques (wedge, punch, needle‐core) for STS in dogs. Medical records of 68 dogs diagnosed with a STS via pre‐treatment biopsy and confirmed by excisional biopsy were evaluated. The concordance in grade between excisional and pre‐treatment biopsies was 59%. Of the 41% that lacked concordance, 29% of pre‐treatment biopsies underestimated and 12% overestimated grade. The method of pre‐treatment biopsy did not significantly effect grade concordance. Based on these data, needle‐core biopsy appears to be similar in accuracy compared to open biopsy, however, grading determined by pre‐treatment biopsy in general should be interpreted with caution.     

Ultrasound-guided liver biopsy in birds

In this study, 30 pigeons (Columba livia forma domestica) and 30 quails (Coturnix coturnix) were used to evaluate the diagnostic practicability and relevance of an ultrasound-conducted liver biopsy. Their body weight ranged between 144 and 603g. Considering anatomical peculiarities, the lateral (pigeons) or ventro-median (quails) access was chosen. In the case of the pigeons, 29 (96.7%) biopsies proved clearly to be liver tissue, while in the case of the smaller quails, 19 (63.3%) samples could be clearly identified as liver tissue. All animals but one quail survived the intervention. The blood chemical parameters varied before and after the biopsy within the physiological range. These results show that ultrasound-guided liver biopsy in avian patients is generally possible and with strict indication and conscientious application can be considered as a relatively risk free and diagnostically sensible addition to liver diagnostic in birds. An aimed collection of focal hepatic alterations is conceivable depending on the size of the patient.     

Diagnostic accuracy of pre‐treatment biopsy for grading cutaneous mast cell tumours in dogs

Mast cell tumours (MCTs) are common tumours of the canine skin, and are estimated to represent up to 20% of all skin tumours in dogs. Tumour grade has a major impact on the incidence of local recurrence and metastatic potential. In addition to helping the clinician with surgical planning, knowledge of the tumour grade also assists in proper prognostication and client education. For pre‐treatment biopsies to be useful, there must exist a high level of correlation between the histopathological grade obtained from the pre‐treatment biopsy and the actual histopathological grade from the excisional biopsy. The aim of this study was to determine concordance of tumour grade between various biopsy techniques (wedge, punch, needle core) and the “gold standard” excisional biopsy method. We found an overall concordance rate of 96% based on the Patnaik grading system, and an overall concordance rate of 92% based on the Kiupel grading system. The accuracy of the various biopsy techniques (wedge, punch and needle core) when compared with excisional biopsy was 92%, 100% and 100%, respectively, based on the Patnaik grading system, and 90%, 95% and 100%, respectively, based on the Kiupel grading system. Of the cases with discordant results, the pre‐treatment biopsies tended to underestimate the grade of the tumour. Based on these results, we conclude that pre‐treatment biopsies are sufficiently accurate for differentiating low‐grade from high‐grade MCTs, regardless of biopsy technique or tumour location.     

Pilot evaluation of a vacuum-assisted biopsy instrument for percutaneous renal biopsy in dogs

Kidney biopsies in dogs are commonly obtained using automated spring-loaded biopsy instruments. Interpretation of biopsies from dogs with glomerular disease requires examination of at least 5-10 glomeruli, with at least two biopsies usually required for full evaluation. The purpose of this study was to compare quality and interpretability of renal biopsies obtained from healthy dogs with a large-gauge, vacuum-assisted biopsy instrument versus two biopsies obtained with a spring-loaded biopsy needle. Twenty dogs were randomized into two groups, and percutaneous, ultrasound-guided renal biopsies were evaluated using standard criteria. There were no significant differences in the number of biopsies that contained renal tissue, cortex, or medulla. Biopsies obtained with either instrument contained an adequate number of glomeruli and an equivalent number of arterioles and severity of tissue compression. Differences included easier penetration of the renal capsule and collection of sufficient tissue for interpretation with only one instrument pass when using the vacuum-assisted device (vs two passes required with the spring-loaded instrument). Before use in client-owned dogs, future studies should evaluate whether these differences are clinically relevant advantages in the diagnostic evaluation of dogs with kidney disease, and determine the prevalence and severity of complications when using this larger gauge device.     

Transendoscopic biopsy of the horse's airway mucosa

Transtracheal wash and bronchoalveolar lavage are diagnostic techniques that have been adopted from human medicine for monitoring inflammatory changes in the airway of the horse. Transendoscopic biopsy has also proven to be a valuable tool for obtaining samples of the airway mucosa in human patients. A transendoscopic technique was developed in this study for obtaining a respiratory mucosal biopsy from standing, sedated horses. Six normal adult horses were sampled at eight-week intervals for a total of three sample periods. Horses were monitored for adverse effects of the technique and none were noted. Sample sites were completely healed after eight weeks with no gross or histologic abnormalities. Biopsy samples were 3 to 4 millimeters in diameter, and 17 of 18 samples provided interpretable histological sections. Methods for handling, staining and evaluating tissue were also developed. The results of this study demonstrated that airway mucosal biopsy is a safe, repeatable technique that can be performed in the sedated, standing horse.     

Histologic comparison of skin biopsy specimens collected by use of carbon dioxide or 810-nm diode lasers from dogs

OBJECTIVE: To compare histologic artifacts caused by carbon dioxide (CO2) or 810-nm diode surgical lasers used to obtain small biopsy specimens of skin from healthy dogs. DESIGN: Prospective study. ANIMALS: 4 dogs. PROCEDURE: 21 skin biopsy specimens were collected from each dog. Three biopsy specimens were obtained with a CO2 or an 810-nm diode laser at 3 operating settings each, and 3 biopsy specimens were obtained with a 6-mm biopsy punch instrument (controls). After processing, biopsy specimens were examined for artifacts related to laser-tissue interactions. Microscopically visible char was measured from the lateral edge of each specimen obtained with a laser. RESULTS: There were no significant differences among mean char distances in biopsy specimens obtained with the CO2 laser at various settings. Mean char distance was significantly greater in all skin biopsy specimens obtained with the diode laser, compared with those obtained with the CO2 laser. Mean char distance was significantly greater in biopsy specimens obtained with the 810-nm diode laser at high power, compared with biopsy specimens obtained with the 810-nm diode laser at low power. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the CO2 laser caused less thermal injury at margins of skin biopsy specimens; therefore, if a surgical laser is used for removal of cutaneous masses or to obtain skin biopsy specimens, use of the CO2 laser is recommended. Veterinarians performing a biopsy by using a surgical laser should be aware that laser-induced artifacts may render small biopsy specimens useless for providing accurate histologic diagnosis.     

Percutaneous biopsy of abdominal organs under ultrasound guidance

Percutaneous sampling of one or more abdominal organs was performed under ultrasound guidance in 89 dogs and 16 cats. Tissue core samples were considered to be of diagnostic quality in 92 per cent of hepatic and 100 per cent of renal biopsies. Core biopsies were collected from the prostate in only three cases but each was adjudged of diagnostic quality. The technique allowed a definitive diagnosis or normal tissue to be confirmed in 65 per cent of animals undergoing hepatic biopsy, 83 per cent undergoing renal biopsy and 82 per cent undergoing prostatic biopsy or aspiration. Few complications occurred which could be ascribed with certainty to the procedure. One dog with extensive hepatic necrosis died one week after the biopsy, but necropsy examination was denied. One severely debilitated cat did not recover from general anaesthesia. One dog underwent aspiration of a sterile intraprostatic cyst, and developed prostatic abscessation one week later; prostatic carcinoma was subsequently found. Careful selection and preparation of patients for biopsy are essential. With this caveat, ultrasound-guided sampling of abdominal organs is a useful technique allowing a definitive diagnosis in a high proportion of cases. The technique is minimally invasive and the complication rate low.     

Computed tomography-guided fine-needle aspiration and tissue-core biopsy of bone lesions in small animals

In humans, free-hand computed tomography (CT)-guided biopsy is an accurate method to obtain a tissue sample. There are only a few reports of this technique in veterinary medicine. In the present study, 21 dogs and two cats underwent a free-hand CT-guided tissue-core biopsy (17 animals) or fine-needle aspiration (six animals) of a bone lesion. Two out of 17 tissue-core samples were also cultured. All 17 tissue-core biopsy samples were diagnostic (accuracy of 100%). Five out of six aspirates were diagnostic (accuracy of 83.3%). The overall accuracy was 95.7%. In one aspirate, cytologic quality was insufficient containing only blood. No major complications were encountered. Fourteen neoplastic, two infectious and six benign lesions were diagnosed. CT examination after intravenous contrast medium added useful information to avoid large vessels and to biopsy-viable tissue. Free-hand CT-guided tissue-core biopsy and aspiration appears to be a safe and very accurate procedure for use in the diagnosis of bone-associated diseases in small animals.     

Histologic comparison of canine skin biopsies collected using monopolar electrosurgery, CO2 laser, radiowave radiosurgery, skin biopsy punch, and scalpel

OBJECTIVE: To compare the histologic appearance of canine skin biopsies collected by use of a scalpel, skin biopsy punch, monopolar electrosurgery, CO2 laser, and radio wave radiosurgery in fully rectified wave form (RWRS). STUDY DESIGN: Experimental, randomized design. ANIMALS: Healthy adult grayhounds (n=4). METHODS: Skin biopsies were collected using 5 techniques. Cut margins of biopsy specimens and adjacent peripheral skin were evaluated using light microscopy to compare penetration of the dermis by tissue carbonization (char). RESULTS: No char occurred in skin specimens collected by biopsy punch and scalpel. Char penetration occurred in all specimens collected by electrosurgery, CO2 laser, and RWRS. Mean char penetration in skin biopsies collected by RWRS (0.158 mm) was significantly less than for monopolar electrosurgery (0.223 mm) and CO2 laser (0.215 mm). Mean char penetration in adjacent peripheral skin surrounding biopsies collected by RWRS (0.171 mm) was significantly less than monopolar electrosurgery (0.255 mm) but not less than CO2 laser (0.215 mm, P<.07). CONCLUSIONS: RWRS (blended waves in cut-coagulate mode) caused less lateral thermal damage to canine skin biopsies than monopolar electrosurgery and CO2 laser and less lateral thermal injury to peripheral skin than monopolar electrosurgery. CLINICAL RELEVANCE: Excision of canine skin biopsies with heat-generating devices may not allow reliable histologic interpretation, particularly when assessing margins of small biopsy specimens. RWRS may be less traumatic to canine skin than monopolar electrosurgery and CO2 laser when used to make incisions.     

Evaluation of a laparoscopic technique for collection of serial full-thickness small intestinal biopsy specimens in standing sedated horses

OBJECTIVE: To assess a technique for laparoscopic collection of serial full-thickness small intestinal biopsy specimens in horses. ANIMALS:13 healthy adult horses. PROCEDURES: In the ex vivo portion of the study, sections of duodenum and jejunum obtained from 6 horses immediately after euthanasia were divided into 3 segments. Each segment was randomly assigned to the control group, the double-layer hand-sewn closure group, or the endoscopic linear stapler (ELS) group. Bursting strength and bursting wall tension were measured and compared among groups; luminal diameter reduction at the biopsy site was compared between the biopsy groups. In the in vivo portion of the study, serial full-thickness small intestinal biopsy specimens were laparoscopically collected with an ELS from the descending duodenum and distal portion of the jejunum at monthly intervals in 7 sedated, standing horses. Biopsy specimens were evaluated for suitability for histologic examination. RESULTS: Mean bursting strength and bursting wall tension were significantly lower in the ELS group than in the hand-sewn and control groups in both the duodenal and jejunal segments. Use of the hand-sewn closure technique at the biopsy site reduced luminal diameter significantly more than use of the stapling technique. In the in vivo part of the study, all 52 biopsy specimens collected during 26 laparoscopic procedures were suitable for histologic examination and no clinically important perioperative complications developed. CONCLUSIONS AND CLINICAL RELEVANCE: Laparoscopic collection of serial full-thickness small intestinal biopsy specimens with a 45-mm ELS may be an effective and safe technique for use in healthy adult experimental horses.     

Comparison of endoscopic and full-thickness biopsy specimens for diagnosis of inflammatory bowel disease and alimentary tract lymphoma in cats

OBJECTIVE: To evaluate the accuracy of endoscopic biopsy (EB) specimens for diagnosis of alimentary tract lymphosarcoma in cats. DESIGN: Prospective study. ANIMALS: 22 cats with inflammatory bowel disease (IBD) or alimentary tract lymphosarcoma. PROCEDURES: Endoscopic biopsy specimens were obtained during endoscopy of the stomach and duodenum immediately prior to laparotomy or laparoscopic surgery, during which full-thickness biopsy (FTB) specimens were obtained. Accuracy of histopathologic diagnoses was compared between EB and FTB specimens. RESULTS: Lymphosarcoma was diagnosed in 10 cats on the basis of FTB specimens. Lymphosarcoma was detected in the jejunum and ileum in all 10 cats, in the duodenum in 9 cats, and in the stomach in 4 cats. In the same 10 cats, EB findings indicated a diagnosis of lymphosarcoma in 3 cats and were suggestive but inconclusive for lymphosarcoma in 3 cats. Lymphosarcoma was correctly diagnosed via gastric EB specimens in 3 of the 4 cats with gastric lymphosarcoma but evaluation of EB specimens led to an incorrect diagnosis of IBD in 4 cats with small intestinal lymphosarcoma. CONCLUSIONS AND CLINICAL RELEVANCE: EB specimens were useful for diagnosis of gastric lymphosarcoma but were not adequate for differentiating between IBD and lymphosarcoma in the small intestine. Because the most common sites of alimentary tract lymphosarcoma in cats are the jejunum and ileum, FTB specimens of those sites should be obtained via laparotomy or laparoscopy for accurate diagnosis. Laparoscopy may be a minimally invasive alternative to endoscopy and laparotomy for obtaining diagnostic biopsy specimens.     

Nasal hydropulsion: a novel tumor biopsy technique

Intranasal tumors of dogs and cats pose a diagnostic and therapeutic challenge for small animal practitioners. Multiple nasal biopsy techniques have been described in the past. This report describes a simplified flushing technique to biopsy and debulk nasal tumors, which often also results in immediate clinical relief for the patient. Based on the results of this retrospective study, the authors recommend high-pressure saline hydropulsion as a minimally invasive diagnostic, and potentially therapeutic, technique for nasal tumors in dogs and cats.     

Comparison of three intestinal cannulas used to obtain repeated biopsy of the jejunal mucosa in the newborn calf

This project was designed to develop a standardized cannulation technique which would allow repeated jejunal mucosal biopsy. Three intestinal cannulas of various designs were evaluated in a total of 25 neonatal calves. Cannula A, a T-design made of acrylic plastic, was implanted into the jejunum (2) or duodenum (7). Cannula A did not allow proper directional passage of the biopsy instrument. Peritonitis was diagnosed at necropsy in 4 calves. Cannula B, a modification of A with an angled port to facilitate the directional passage of the biopsy instrument, also proved unsatisfactory. This cannula required a larger enterotomy for placement and resulted in the death of 1 calf. Cannula C was made of tygon tubing with a proxplast mesh flange which was sutured to the serosal surface of the intestine. No intestinal leakage was observed in 14 calves fitted with this cannula. This cannula was the least expensive and allowed the biopsy instrument to be easily directed. Surgical implantation of this cannula (C) in the descending duodenum proved to be an excellent method to obtain successive mucosal biopsies of the jejunum in the neonatal calf.     

Evaluation of hemorrhage, sample size, and collateral damage for five hepatic biopsy methods in dogs

OBJECTIVES: To compare the volume of hemorrhage, number of lobules, and portal triads available for histologic evaluation, and resultant collateral damage between 5 hepatic biopsy methods: biopsy punch, biopsy needle, ligature method, laparoscopic biopsy forceps, and ultrasonically activated scalpel (UAS). STUDY DESIGN: Experimental, repeated measures, block. ANIMALS: Twelve adult dogs. METHODS: Biopsies were obtained from the periphery and center of the left lateral liver lobe of each dog using each of 5 biopsy techniques. Hemorrhage was quantified and compared between methods and sites. Biopsy samples were evaluated histologically to characterize collateral damage and determine the number of lobules and portal triads sampled. RESULTS: Regardless of technique, liver biopsy resulted in minimal hemorrhage (<2 mL). For peripheral biopsies, UAS was comparable with the ligature method, but caused significantly less hemorrhage than all other methods, whereas for central biopsies, UAS caused significantly less hemorrhage than other methods. Except for the laparoscopic biopsy forceps, UAS caused significantly more collateral damage than other methods. UAS and ligature biopsy methods yielded specimens that had more portal triads per sample than other methods. Eight of 48 biopsy needle samples were inadequate for histologic evaluation, whereas other methods yielded adequate specimens. CONCLUSIONS: All biopsy methods produced minimal hemorrhage and except for needle biopsy yielded adequate tissue samples for histologic evaluation. CLINICAL RELEVANCE: Use of UAS is a reliable, safe alternative technique for liver biopsy and can be used laparoscopically to obtain large tissue samples.