Evaluation of the effect of routine histologic processing on the size of skin samples obtained from dogs

A mechanical approach to understanding the impact of the nematode Anguillicoloides crassus on the European eel swimbladder

One of the most detrimental factors in the drastic decline of the critically endangered European eel (Anguilla anguilla) was the inadvertent introduction of the invasive nematode Anguillicoloides crassus Infection primarily affects the swimbladder, a gas-filled organ that enables the eel to control its depth in the water. A reduction in swimbladder function may be fatal for eel undergoing their spawning migration to the Sargasso Sea, a journey of over 5000 km. Although the physiological damage caused by this invasive parasite is well studied through the use of quantifiable gross pathological indices, providing a good measure of the swimbladder health status, they cannot separate the role of mechanical and morphological damage. Our study examined the appropriateness of three commonly used indices as a measure of mechanical damage by performing uniaxial tensile tests on swimbladder specimens obtained from an infected eel population. When the test results were compared with the gross pathological indices it was found that thickness correlated most strongly with mechanical damage, both confirming and, more importantly, explaining the counterintuitive findings of earlier work. In a damaged swimbladder, the immune response leads to a trade-off; increasing wall thickness raises the pressure required for organ rupture but decreases strength. The results indicate that for moderate infection the mechanical integrity of the swimbladder can be maintained. For severe infection, however, a reduction in mechanical integrity may reach a tipping point, thereby affecting the successful completion of their oceanic migration.

Curative-intent radical en bloc resection using a minimum of a 3 cm margin in feline injection-site sarcomas: a retrospective analysis of 131 cases

Objectives Owing to its highly infiltrative growth, feline injection-site sarcoma (FISS) carries a significant risk of local tumour recurrence. Parameters of possible prognostic significance (eg, tumour size and location, resection of de novo vs recurrent tumours, and achievement of tumour-free surgical margins) were examined with regard to their influence on recurrence rate (RR), disease-free interval (DFI) and survival time (ST). Methods This was a retrospective analysis of cats with FISSs located on the chest or abdominal wall or the interscapular region treated in a single institution using a standardised radical resection technique with 3 cm lateral margins and full-thickness body wall resection (tumours over chest/abdominal wall) or a minimum of two fascial planes (interscapular tumours). Results Median postoperative DFI and ST of 131 cats with FISSs was 21 and 24 months, respectively. Patients operated on for recurrent tumours were significantly more likely to die from tumour-related reasons compared with patients with de novo tumours ( P <0.001). RR and DFI in the different tumour locations were comparable ( P = 0.544 and P = 0.17, respectively). Local tumour recurrence occurred in 38.1% of the cats. Cats operated on for tumour recurrences had a significantly higher chance of another recurrence (RR 55.5% vs 33.3%; P = 0.005). Completeness of excision was determined by taking tumour bed biopsies. Tumour bed biopsies that did not contain tumour cells were associated with a significantly lower RR compared with those with tumour cells (30.5% vs 76.2%). Conclusions and relevance Depending on prognostic factors such as surgery for primary vs recurrent tumour, tumour-free resection margins and tumour location, the RR in FISS ranges from 33-55%, despite curative intent radical surgery. This study may help in identifying patients at risk for recurrence.

Evaluation of information presented within soft tissue sarcoma histopathology reports in the United States: 2012-2015

Despite the existence of the American College of Veterinary Pathology guidelines for tumour biopsy specimens, anecdotally the authors' have seen inconsistency of reporting of information on the pathology report for canine soft tissue sarcomas (STSs). If crucial aspects are not reported this can result in slower or impeded patient care. This retrospective study evaluated 255 STS histopathology reports submitted from across the United States. Reports were evaluated by a single observer to assess for information contained in 5 main categories: patient history and signalment, gross and microscopic description, grading, histologic margins and the comments section. Inclusion criteria for histopathology reports included a final diagnosis of STS, having a microscopic description and resulting from the initial surgical resection. The majority of the reports stated the patient signalment (91.2%) and clinical history (90.8%). However, only 64.8% of the reports had a gross description of the specimen. Histologic margin description was present in 229 reports (91.6%), however, only 149 reports (59.6%) stated an objective measurement of these margins. Histologic classification was stated in 50.0% of the reports, while grade was given on 97.2% of the reports. Variability in histopathologic reporting including histologic margin description for resected canine STS was identified. Given surgical treatment is the mainstay for STS and histopathological assessment plays an important role in determination of whether additional surgery, radiation or chemotherapy is needed. Standardization or checklists like the American College of Pathology utilize may be helpful to ensure histopathologic characteristics are reported that may guide further treatment recommendations.

Histologic processing artifacts and inter-pathologist variation in measurement of inked margins of canine mast cell tumors

Although quantitative assessment of margins is recommended for describing excision of cutaneous malignancies, there is poor understanding of limitations associated with this technique. We described and quantified histologic artifacts in inked margins and determined the association between artifacts and variance in histologic tumor-free margin (HTFM) measurements based on a novel grading scheme applied to 50 sections of normal canine skin and 56 radial margins taken from 15 different canine mast cell tumors (MCTs). Three broad categories of artifact were 1) tissue deformation at inked edges, 2) ink-associated artifacts, and 3) sectioning-associated artifacts. The most common artifacts in MCT margins were ink-associated artifacts, specifically ink absent from an edge (mean prevalence: 50%) and inappropriate ink coloring (mean: 45%). The prevalence of other artifacts in MCT skin was 4-50%. In MCT margins, frequency-adjusted kappa statistics found fair or better inter-rater reliability for 9 of 10 artifacts; intra-rater reliability was moderate or better in 9 of 10 artifacts. Digital HTFM measurements by 5 blinded pathologists had a median standard deviation (SD) of 1.9 mm (interquartile range: 0.8-3.6 mm; range: 0-6.2 mm). Intraclass correlation coefficients demonstrated good inter-pathologist reliability in HTFM measurement (κ = 0.81). Spearman rank correlation coefficients found negligible correlation between artifacts and HTFM SDs ( r ≤ 0.3). These data confirm that although histologic artifacts commonly occur in inked margin specimens, artifacts are not meaningfully associated with variation in HTFM measurements. Investigators can use the grading scheme presented herein to identify artifacts associated with tissue processing.

Surgical margins in the veterinary cancer patient

In veterinary oncologic specimens, histopathology is the gold standard for determining adequacy of excision. Despite limitations of this technique, the pathologist's interpretation of margin status significantly impacts patient management, including indications for adjuvant therapy. This article aims to summarize peer-reviewed literature as it relates to histologic margin evaluation in veterinary cancer patients. The value of histologic tumour-free margins and technical factors influencing histopathologic margin outcomes are also discussed. We review alternative strategies for determining excisional status, and discuss how an evolving understanding of tumour biology might inform clinical and research perspectives on surgical margins. In doing so, we aim to provide context and a stimulus for future investigations into this important yet incompletely understood topic.

Four different diode lasers comparison on soft tissues surgery: a preliminary ex vivo study

Objectives: The introduction of diode lasers in dentistry had several advantages, principally consisting on the reduced size, reduced cost and possibility to beam delivering by optical fibbers. Up today only the wavelengths around 810 and 980 nm were the most utilized in oral surgery but recently more different lasers had been proposed. The aim of this study was to compare the efficacy of four diode laser wavelengths (810, 980, 1470 and 1950 nm) for the ablation of soft tissues. Material and methods: Specimens were surgically collected from the dorsal surface of four bovine tongues and irradiated by four different diode wavelengths. Thermal increase was measured by two thermocouples, the first at a depth of 0.5 mm, and the second at a depth of 2 mm. Initial and final surface temperatures were recorded by IR thermometer. Epithelial changes, connective tissue modifications, presence of vascular modification and incision morphology were histologically evaluated by two blind pathologists. Results: The time necessary to perform the excision varied between 271 seconds (808 nm, 2W) and 112 seconds (1950 nm, 4W). Temperature increase superficial level varied from 16.3° (980 nm, 4W) and 9.2° (1950 nm, 2 W). The most significant deep temperature increase was recorded by 980 nm, 4 W (17.3°) and the lowest by 1950 nm, 2 W (9.7°). The width of epithelial tissue injuries varied between 74 pm from 1950 nm diode laser at 2 W to 540 pm for 1470 nm diode laser at 4 W. Conclusion: The quality of incision was better and the width of overall tissue injuries was minor in the specimens obtained with higher wavelength (1950 nm) at lower power (2W).

Effect of feline skin specimen preparation on postexcision and postfixation tissue shrinkage

OBJECTIVES

This study was performed to assess skin-muscle-fascia specimen shrinkage and donor site changes, and to compare three techniques of specimen preparation for their effect on specimen shrinkage postexcision and after formalin fixation in feline cadaveric specimens.

METHODS

Fifteen fresh feline cadavers were used for this study. Gelatin spheres were implanted in paired thoracic subcutaneous pockets and subsequently excised with 30 mm lateral margins and a fascial plane as the deep margin. Skin and fascia were either left unsutured, sutured together using four simple interrupted quadrant sutures ('four-quadrant-sutured') or sutured together in a continuous pattern ('circumferentially sutured'). Specimens were measured for tumor-free margins on the excised and fixed specimens. The donor site defect was assessed for enlargement after specimen excision. Statistical analyses were performed to assess the donor site enlargement, and the influence of preparation technique on margin size, with significance set at P <0.05.

RESULTS

The closest skin margins on the excised and fixed specimens were significantly smaller than the planned 30 mm margins; however, no significant difference was found between postexcision and postfixation specimens. No significant differences were found between the three techniques (P = 0.74) with regard to margins either after excision or fixation. The fascial and skin defects of the donor site were significantly larger than the planned excision.

CONCLUSIONS AND RELEVANCE

Surgically obtained feline skin-muscle-fascia specimens will significantly decrease in size prior to formalin fixation, resulting in falsely decreased measurements from tumor to tissue margins. Affixing the skin to the fascia does not significantly influence this decrease in margin size in feline tissue specimens at this location.

Evaluation of the effect of formalin fixation on skin specimens in dogs and cats

Skin and subcutaneous tissues are the origin of most common neoplasms affecting dogs, accounting for approximately one third of all tumors encountered in the species. Surgical excision is frequently the best chance for a cure; determining factors influencing the success of excision are vital for surgical management of cases. This work examined the shrinkage of skin of various lengths from three sites in formalin for both dogs and cats. Tissues were measured on the animal (initial measurement), at the time of excision (post-removal), and after formalin fixation (post-fixation). While shrinkage after tissue removal was found in samples from the thorax, abdomen, and rear leg in dogs and from the rear leg in cats, no significant shrinkage due to formalin fixation was detected in any sample except for the thoracic samples from the dog. Therefore, when determining where to make incisions to effect a surgical cure, initial measurements should take into account tissue shrinkage effects.

Laser-assisted surgery with different wavelengths: a preliminary ex vivo study on thermal increase and histological evaluation

Since the introduction of laser in clinical practice, different wavelengths have been used for oral surgery on the basis of the different characteristics and affinities of each one. The aim of this study was a comparison of different laser wavelengths in relation to both thermal increase and "histological quality" in a model of soft tissue surgery procedures. Thermal evaluation was realized, during laser-assisted surgery excision performed on a bovine tongue, by a thermal camera device to evaluate thermal increase on the surface of the sample and with four thermocouples to evaluate thermal increase on the depth of the specimen; temperature was recorded before starting surgical procedure and at the peak of every excision. The quality of excision, in terms of tissue damage and regularity, was realized by two blind examiners on the basis of established criteria. The highest superficial thermal increase was recorded for Superpulse 5-W CO2 laser, the lowest one for Er:YAG laser. The highest in depth thermal increase was recorded for 5 W Diode laser, the lowest one for Er:YAG laser. The best quality of incision was obtained with a 3-W CO2 laser and 3-W diode laser; epithelial, stromal, and vascular damages were evaluated with different degrees for all the used wavelengths with the best result, in terms of "tissue respect," for Er:YAG laser. In all the surgical procedures performed, thermal increase was evaluated until the end of the procedure; at remaining tissue level, thermal decrease was evaluable in the few seconds after surgery. The Er:YAG laser was the device with a lower influence on thermal increase; CO2 and diode lasers revealed a good histological quality. Further studies may be necessary to test the reliability of laser devices for the excision of all the types of specimens needing histological evaluation and diagnosis.

Nd:YAG laser versus traditional scalpel. A preliminary histological analysis of specimens from the human oral mucosa

Hyperplastic fibro-epithelial lesions are the most common tumor-like swellings in the mouth. The neodymium yttrium aluminium garnet (Nd:YAG) laser appears to be useful for the surgical treatment of these lesions. Some controversies of laser surgery concern the accuracy of pathological diagnosis as well as the control of thermal damage on the target tissue. The aim of this study was to establish if the thermal changes induced by the Nd:YAG laser may affect the histopathological diagnosis and the evaluation of the resection margins. Furthermore, we compared the histological features of oral benign fibro-epithelial lesions excised through Nd:YAG laser and traditional scalpel. Twenty-six benign fibro-epithelial oral lesions from 26 patients, localized in the same oral subsites (cheek and buccal mucosa), were collected at the Unit of Oral Pathology and Oral Laser-assisted Surgery of the Academic Hospital of the University of Parma, Italy. Specimens were subclassified into three groups according to the tool used for the surgical excision. Group 1 included six specimens excised through Nd:YAG laser with an output power of 3.5 W and a frequency of 60 Hz (power density 488,281 W/cm2); Group 2 included nine specimens excised through Nd:YAG laser with an output power of 5 W and a frequency of 30 Hz; Group 3 included 11 specimens excised through a Bard-Parker scalpel blade no. 15c. Epithelial changes, connective tissue modifications, presence of vascular modifications, incision morphology and the overall width of tissue modification were evaluated. Differences between specimens removed with two different parameters of Nd:YAG laser were not significant with regard to stromal changes (p=0.4828) and vascular stasis (p=0.2104). Analysis of regularity of incision revealed a difference which was not statistically significant (p=1.000) between group 1 and group 2. Epithelial and stromal changes were significantly more frequent in specimens with a mean size less than 7 mm (p<0.0001). Nd:YAG laser induced serious thermal effects in small specimens (mean size less than 7 mm) independently from the frequency and power employed. The quality of incision was better and the width of overall tissue injuries was less in the specimens obtained with higher frequency and lower power (group 1: Nd:YAG laser at 3.5 W and 60 Hz).

Validation of carotid arterial wall volume measurement by cardiovascular magnetic resonance

PURPOSE

To validate cardiovascular magnetic resonance (CMR) arterial wall volume measurement using whole arterial specimens ex vivo.

MATERIALS AND METHODS

Twenty cadaveric carotid arteries (from 10 patients) were fixed in formaldehyde and imaged with a clinical T1-weighted 2D CMR sequence and, for imaging validation, with a high-resolution 3D sequence. Histological validation was performed by sectioning the arteries and microscopically determining area and volume.

RESULTS

Comparison between the clinical 2D CMR sequence and the 3D high-resolution validation sequence showed equivalent luminal volumes (889 vs. 880 mm(3); P = 0.54; R(2) = 0.99), and slightly higher 2D CMR arterial wall volumes (982 vs. 916 mm(3); +7%; P < 0.01; R(2) = 0.96) and adventitial volumes (1901 vs. 1826 mm(3); +4%; P < 0.01; R(2) = 0.99). Comparison between 2D CMR and microscopy, performed over a similar longitudinal extent of vessel, showed slightly higher 2D CMR volumes for the lumen (354 vs. 308 mm(3); +14%; P < 0.01; R(2) = 0.97), arterial wall (388 vs. 351 mm(3); +10%; P < 0.01; R(2) = 0.97) and total volumes (750 vs. 665 mm(3); +12%; P < 0.01; R(2) = 0.95).

CONCLUSION

The accuracy of the clinical 2D CMR vessel wall sequence for measuring carotid lumen, adventitial, and wall volumes is good against ex vivo measurements, with minor overestimation. This study validates carotid arterial wall quantification by CMR for atherosclerosis research.

Ultrasound imaging accurately detects skin thickening in a mouse scleroderma model

Systemic sclerosis (scleroderma) is characterized by initial thickening of the skin because of the accumulation of collagen within the dermis followed by progression of fibrosis to internal organs. Although ultrasound assessment of dermal thickening in scleroderma patients is well documented, whether this technique can accurately detect skin thickening in mice under similar disease conditions is not known. Unlike traditional histologic assessments performed for disease models, ultrasound does not require sacrifice of the animal, and assessments of the same individual mice can be made over time. For these reasons, we examined the feasibility of ultrasound imaging to detect changes in skin thickness in a mouse model of graft-vs.-host-induced scleroderma (GVH-scleroderma). These studies determined ultrasound measurements to be highly consistent, both between multiple measurements of the same mouse as well as within a group of normal mice (coefficient of variation <8%). Ultrasound analysis of skin thickening in a GVH-scleroderma model showed similar sensitivity to histologic measurements because changes in skin thickness were detected by both methods at similar time points and to similar degrees. Direct comparisons between histologic and ultrasound measurements in the same animals over the course of disease also demonstrated significant correlations. Thus, these studies demonstrate that ultrasound can accurately detect skin thickening in a mouse model of scleroderma.

Immediate tight sealing of skin incisions using an innovative temperature-controlled laser soldering device: in vivo study in porcine skin

BACKGROUND

A feedback temperature-controlled laser soldering system (TCLS) was used for bonding skin incisions on the backs of pigs. The study was aimed: 1) to characterize the optimal soldering parameters, and 2) to compare the immediate and long-term wound healing outcomes with other wound closure modalities.

MATERIALS AND METHODS

A TCLS was used to bond the approximated wound margins of skin incisions on porcine backs. The reparative outcomes were evaluated macroscopically, microscopically, and immunohistochemically.

RESULTS

The optimal soldering temperature was found to be 65 degrees C and the operating time was significantly shorter than with suturing. The immediate tight sealing of the wound by the TCLS contributed to rapid, high quality wound healing in comparison to Dermabond or Histoacryl cyanoacrylate glues or standard suturing.

CONCLUSIONS

TCLS of incisions in porcine skin has numerous advantages, including rapid procedure and high quality reparative outcomes, over the common standard wound closure procedures. Further studies with a variety of skin lesions are needed before advocating this technique for clinical use.

Histologic Comparison of Canine Skin Biopsies Collected Using Monopolar Electrosurgery, CO2Laser, 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.