A 4-year-old 14.5-kg (31.9-lb) spayed female French Bulldog was referred to the University of Georgia College of Veterinary Medicine Veterinary Teaching Hospital for treatment of a suspected right-sided nasal angiofibroma associated with a 4-month history of waxing-and-waning unilateral mucoid nasal discharge and stertorous breathing. Four months earlier, the dog had been evaluated by the owner's primary veterinarian because of right-sided mucoid nasal discharge and a single episode of unilateral epistaxis. Results of a PCR assay panel for canine respiratory tract disease performed at that time were negative, and the dog was treated with doxycycline (6.8 mg/kg [3.1 mg/lb], PO, q 12 h for 30 days), diphenhydramine (2.5 mg/kg [1.1 mg/lb], PO, q 8 h for 30 days), cetirizine (1 mg/kg [0.45 mg/lb], PO, q 24 h for 14 days), and loratadine (1 mg/kg, PO, q 12 h for 14 days). However, there was no improvement in the dog's clinical signs. Despite the signs of upper respiratory tract disease, the dog reportedly was healthy, other than episodic diarrhea attributed to food sensitivity to poultry products.
Computed tomography performed at a separate referral center had revealed a moderate amount of contrast-enhancing soft tissue–attenuating material in the mid to caudal, ventral aspect of the right nasal cavity (Figure 1). The lesion extended caudally to the right aspect of the choanae and appeared to breach the nasal septum. Moderate right-sided turbinate lysis was documented without evidence of lysis of the adjacent bones or cribriform plate. The frontal sinuses, dentition, brain, and orbits appeared to be unaffected. Results of a preanesthetic CBC and serum biochemical analyses were unremarkable, and nasal biopsy was performed through the right naris following CT. Three 5- to 8-mm tissue samples were collected; 2 were submitted for histologic examination, and 1 was submitted for aerobic bacterial culture. Histologic assessment of the samples revealed a proliferation of vascular-appearing structures lined by a single layer of endothelial or epithelial cells with plump, uniform nuclei. Throughout the samples, large dilated blood vessels were observed. There was minimal nuclear and cellular pleomorphism and no evidence of mitotic figures. Evaluation of the surrounding submucosa revealed fibrosis, reactive turbinate bone, hemorrhage, and infiltration of neutrophils, lymphocytes, plasma cells, and occasional hemosiderophages. The mucosa appeared hyperplastic with invagination into the submucosa. A tentative diagnosis of an inflammatory fibrovascular polyp (nasal angiofibroma) was made following review by 3 pathologists. Aerobic bacterial culture of the biopsy sample did not yield any growth after 72 hours.
Transverse CT images of a 4-year-old French Bulldog with a 4-month history of waxing-and-waning unilateral mucoid nasal discharge and stertorous breathing. On initial images viewed in soft tissue (A) and bone (B) windows, a soft tissue–attenuating, space-occupying mass can be seen in the right nasal passage, along with apparent destruction of the nasal septum. Eight months after the mass was removed by means of lateral rhinotomy and coblation, images viewed in soft tissue (C) and bone (D) windows did not show any evidence of mass regrowth, although some blunting of the nasal turbinates is apparent.
Citation: Journal of the American Veterinary Medical Association 256, 11; 10.2460/javma.256.11.1257
Transverse CT images of a 4-year-old French Bulldog with a 4-month history of waxing-and-waning unilateral mucoid nasal discharge and stertorous breathing. On initial images viewed in soft tissue (A) and bone (B) windows, a soft tissue–attenuating, space-occupying mass can be seen in the right nasal passage, along with apparent destruction of the nasal septum. Eight months after the mass was removed by means of lateral rhinotomy and coblation, images viewed in soft tissue (C) and bone (D) windows did not show any evidence of mass regrowth, although some blunting of the nasal turbinates is apparent.
Citation: Journal of the American Veterinary Medical Association 256, 11; 10.2460/javma.256.11.1257
Transverse CT images of a 4-year-old French Bulldog with a 4-month history of waxing-and-waning unilateral mucoid nasal discharge and stertorous breathing. On initial images viewed in soft tissue (A) and bone (B) windows, a soft tissue–attenuating, space-occupying mass can be seen in the right nasal passage, along with apparent destruction of the nasal septum. Eight months after the mass was removed by means of lateral rhinotomy and coblation, images viewed in soft tissue (C) and bone (D) windows did not show any evidence of mass regrowth, although some blunting of the nasal turbinates is apparent.
Citation: Journal of the American Veterinary Medical Association 256, 11; 10.2460/javma.256.11.1257
The dog was referred to the University of Georgia College of Veterinary Medicine for radiation treatment of the suspected nasal angiofibroma. On initial examination, the dog was bright and alert with appropriate mentation and response to stimulation. Both globes could be retropulsed normally with no signs of discomfort. Results of an oral examination were unremarkable, and no signs of pain were observed when opening the mouth. The nares were found to be stenotic on visual examination. Mucoid debris was observed adhered to the ventral aspect of the right naris. Airflow through the right naris was estimated to be < 30% of the airflow through the left naris. No other abnormalities were detected on physical examination.
Radiation therapy was discussed with the owners. However, in collaboration with one of the owners, who was a specialist in human head and neck surgery and was well versed in treatments used for benign nasal tumors in humans, the decision was made to instead perform a right lateral rhinotomy with endoscopic evaluation and coblation of the mass. Coblation is a process that involves applying radiofrequency energy to a conductive medium such as saline solution, resulting in formation of a plasma field around the electrode. The plasma field is composed of highly ionized particles whose energy breaks molecular bonds in the mass. There is minimal collateral tissue damage with coblation because there is minimal heat generation.
In preparation for the procedure, the dog was anesthetized and positioned in sternal recumbency with its head lifted off the surgical table and stabilized with sandbags. Sternal, rather than lateral, recumbency was chosen because this positioning allowed for rhinoscopy of the left, presumably normal, nasal cavity and was the position most often used by individuals participating in the surgery when performing rhinoscopy. The nose and muzzle were aseptically prepared and draped in standard fashion. To allow for insertion of the rigid endoscopes and coblation unit wand, a lateral rhinotomy was performed by making an incision starting at the alar fold and extending just lateral to the nasal planum to the dorsal midline. The right half of the nasal planum was then elevated laterally and dorsally to allow access to the right nasal cavity (Figure 2). Rigid endoscopes (0° and 30°) were used to examine the right nasal cavity. The mass was found to fill the anterior aspect of the nasal cavity and involved a portion of the nasal turbinates with some erosion (Figure 3). In contrast to CT findings, the mass was in contact with the nasal septum but had not breached it. There was a nodular, frond-like appearance to the medial aspect of the tumor. The tumor extended to and obstructed the choana.
Intraoperative photographs showing the lateral rhinotomy performed in the dog in Figure 1 with (A) and without (B) medial displacement of the nasal planum.
Citation: Journal of the American Veterinary Medical Association 256, 11; 10.2460/javma.256.11.1257
Intraoperative photographs showing the lateral rhinotomy performed in the dog in Figure 1 with (A) and without (B) medial displacement of the nasal planum.
Citation: Journal of the American Veterinary Medical Association 256, 11; 10.2460/javma.256.11.1257
Intraoperative photographs showing the lateral rhinotomy performed in the dog in Figure 1 with (A) and without (B) medial displacement of the nasal planum.
Citation: Journal of the American Veterinary Medical Association 256, 11; 10.2460/javma.256.11.1257
Intraoperative rhinoscopic images of the mass (asterisk) in the lateral portion of the right nasal passage (A) in the dog in Figure 1. Notice that the nasal septum (dagger) does not appear to be affected (B).
Citation: Journal of the American Veterinary Medical Association 256, 11; 10.2460/javma.256.11.1257
Intraoperative rhinoscopic images of the mass (asterisk) in the lateral portion of the right nasal passage (A) in the dog in Figure 1. Notice that the nasal septum (dagger) does not appear to be affected (B).
Citation: Journal of the American Veterinary Medical Association 256, 11; 10.2460/javma.256.11.1257
Intraoperative rhinoscopic images of the mass (asterisk) in the lateral portion of the right nasal passage (A) in the dog in Figure 1. Notice that the nasal septum (dagger) does not appear to be affected (B).
Citation: Journal of the American Veterinary Medical Association 256, 11; 10.2460/javma.256.11.1257
The wand of the coblation unita was introduced into the nasal cavity and used to remove the tumor from the turbinates (coblation setting, 7; coagulation setting, 3). The activated portion of the wand was used to ablate tumor tissue laterally to remove the tumor in piecemeal fashion. As tumor tissue was resected, it became evident that the tumor was based laterally near the area of the sphenopalatine foramen. As the base of the tumor was approached, bleeding was encountered and was controlled with monopolar electrocautery. After visible portions of tumor were removed, the wand was used to ablate the area laterally at the origin of the tumor. Large pieces of the tumor were submitted for histologic examination.
After removal of the tumor, the entire nasal passage was evaluated rhinoscopically, and no further grossly abnormal tissue was observed. Surgical hemostatic powderb was sprayed in the right nasal cavity over the area of tumor resection to stop mild hemorrhage. The nasal planum was released, and the initial incision was apposed with simple interrupted sutures of 4-0 poliglecaprone 25 in 2 layers, a subcutaneous layer and an external skin layer. A vertical wedge rhinoplasty was performed bilaterally to correct the patient's stenotic nares.
The patient recovered from anesthesia without any difficulties and was monitored overnight for evidence of hemorrhage and dyspnea. Carprofen (2.2 mg/kg [1.0 mg/lb], SC, q 12 h) and buprenorphine (0.03 mg/kg [0.014 mg/lb], IV, q 6 to 8 h) were administered for pain control. Only minor epistaxis was encountered after surgery. The patient was discharged without complications the following morning with instructions to restrict activity and to wear an Elizabethan collar until follow-up examination in 10 to 14 days.
Histologic assessment of the submitted tissue sample revealed numerous subepithelial and submucosal cystic glands lined by cytokeratin-immunopositive respiratory epithelium and supported by a fibrovascular submucosal tissue. Anisocytosis and anisokaryosis were mild with no mitotic figures observed (Figure 4). An incompletely excised nasal adenomatoid hamartoma was diagnosed on the basis of cytokeratin stain uptake and lack of an endothelial component. The location and histologic features were consistent with an REAH.
Photomicrographs of sections of the mass from the dog in Figure 1. The submucosa is expanded by numerous cystic spaces (asterisk) filled with eosinophilic fluid and lined by a combination of pseudostratified ciliated columnar (respiratory) epithelium and a single layer of often-attenuated, low cuboidal epithelial cells. The cysts are supported by fibrovascular stroma, cartilage, and scattered bone. H&E stain; bar = 200 μm. Inset—Respiratory (arrow) and cuboidal (arrowheads) epithelia lining cystic spaces were strongly immunopositive for cytokeratin AE1/AE3. Immunohistochemical stain for cytokeratin AE1/ AE3 with hematoxylin counterstain; bar = 20 μm.
Citation: Journal of the American Veterinary Medical Association 256, 11; 10.2460/javma.256.11.1257
Photomicrographs of sections of the mass from the dog in Figure 1. The submucosa is expanded by numerous cystic spaces (asterisk) filled with eosinophilic fluid and lined by a combination of pseudostratified ciliated columnar (respiratory) epithelium and a single layer of often-attenuated, low cuboidal epithelial cells. The cysts are supported by fibrovascular stroma, cartilage, and scattered bone. H&E stain; bar = 200 μm. Inset—Respiratory (arrow) and cuboidal (arrowheads) epithelia lining cystic spaces were strongly immunopositive for cytokeratin AE1/AE3. Immunohistochemical stain for cytokeratin AE1/ AE3 with hematoxylin counterstain; bar = 20 μm.
Citation: Journal of the American Veterinary Medical Association 256, 11; 10.2460/javma.256.11.1257
Photomicrographs of sections of the mass from the dog in Figure 1. The submucosa is expanded by numerous cystic spaces (asterisk) filled with eosinophilic fluid and lined by a combination of pseudostratified ciliated columnar (respiratory) epithelium and a single layer of often-attenuated, low cuboidal epithelial cells. The cysts are supported by fibrovascular stroma, cartilage, and scattered bone. H&E stain; bar = 200 μm. Inset—Respiratory (arrow) and cuboidal (arrowheads) epithelia lining cystic spaces were strongly immunopositive for cytokeratin AE1/AE3. Immunohistochemical stain for cytokeratin AE1/ AE3 with hematoxylin counterstain; bar = 20 μm.
Citation: Journal of the American Veterinary Medical Association 256, 11; 10.2460/javma.256.11.1257
During a recheck assessment 2 weeks after surgery, there was mild erythema with lateral swelling and crusting of the nares. Airflow was symmetric with an improvement in the degree of stertor. Eleven weeks after surgery, the nares appeared healed and were larger, compared with their appearance prior to surgery, because of the vertical wedge rhinoplasties. Eight months after surgery, follow-up CT revealed right-sided nasal turbinate and conchal atrophy consistent with prior mass ablation. No macroscopic recurrence was detected. Twenty-seven months after surgery, the dog was reportedly healthy with only rare, clear bilateral rhinorrhea reported by the owners.
Discussion
The case described in the present report had 3 unique features: identification of an REAH in a relatively young dog; use of a multidisciplinary approach to treatment that involved specialists in veterinary internal medicine, oncology, and surgery and a specialist in human head and neck surgery; and use of coblation for tumor removal.
Hamartomas are thought to be disordered growths of indigenous tissue that may have an underlying congenital, inflammatory, or viral cause.1–4 Hamartomas have been reported in association with the skin, oral mucosa, vertebral column, CNS, and abdominal, cardiac, and ocular tissues in dogs and cats.5–10 In addition, there are rare reports of REAHs in dogs, cats, and humans.1,11,12,c
In humans, REAHs are rarely invasive or associated with turbinate lysis. Turbinate lysis has been documented in dogs with REAHs but has been suspected to be a result of tumor compression rather than invasion.1 Previous reports1,11,c of dogs and cats with REAHs typically described prolonged survival times following complete surgical excision with no reports of metastases.
Histologically, these lesions appear as excessive growth of distended glands and cystic tissue lined with respiratory epithelium within a fibrous matrix background.1,11 A chondro-osseous matrix may also be present, denoting a subtype referred to as chondro-osseous REAH.1 Anisocytosis and anisokaryosis are mild if present, with no or only a few mitoses.1,c We suspect that some previous cases may have been misdiagnosed as a result of the lining cells being incorrectly identified as endothelium,13 as was the case for the first biopsy samples submitted for the dog described in the present report. Immmunohistochemical staining for cytokeratin is needed to highlight the flattened epithelial cells lining cystic spaces.
Coblation is an ablative procedure that functions by passing bipolar radiofrequency energy through a conductive medium such as sodium chloride solution. The radiofrequency disassociates the sodium and chloride ions to form a high-energy plasma field, and the plasma field destroys intercellular bonds, resulting in volumetric reduction of the target tissues.14 Bipolar radiofrequency ablation also results in rapid coagulation of target blood vessels with suspected long-term venous depletion.15 In addition, bipolar radiofrequency ablation has been associated with less thermogenic injury than traditional ablative techniques that require temperatures of 60°C to 70°C (140°F to 158°F).15–18 Whether coblation is preferred to other ablation methods for human patients with otolaryngologic conditions depends, to some extent, on clinician preference. However, the benefits of coblation in the treatment of human patients with nasopharyngeal, tonsillar, and apneic disorders have been documented. Despite reported variations in treatment outcome,16,17,19–22 some studies20–22 have documented improvements in intraoperative blood loss, operative time, postoperative pain, and return to function with coblation.
To our knowledge, clinical use of coblation in veterinary medicine has not been reported previously. In the case described in the present report, coblation was used because of its vascular attenuating properties, resulting in minimal to no postoperative hemorrhage. The surgical approach required lateral rhinotomy and rhinoscopy in conjunction with the ablative technique, which were associated with minimal adverse events and a short recovery time. However, in a larger dog with normally sized nares, lateral rhinotomy likely would not have been necessary. Lateral rhinotomy was less invasive than dorsal rhinotomy, which would have been required if radiation therapy had been declined and surgical excision was elected but coblation had not been available.
Radiation therapy remains the gold standard for treatment of most intranasal neoplasms in companion animals. Considerations related to the use of curative-intent radiation therapy in the young dog described in the present report included a lack of information on radiation responsiveness of REAHs in dogs and the potential for late effects, including chronic rhinitis. Concerns related to the use of coblation included the lack of information on long-term outcome following treatment of REAHs in dogs and concerns about whether coblation-induced vascular damage could result in chronic tissue hypoxia, thus minimizing the benefit of future radiation therapy if needed because of tumor recurrence.23 In addition, margin assessment is compromised with coblation because of thermal damage of the tissue borders. Thus, tumors associated with a high risk of recurrence following incomplete excision may not be ideal candidates for coblation. Tumors with minimal invasion and low metastatic potential and for which marginal excision results in long-term control would be better candidates for coblation. Future opportunities for the use of coblation may involve dermal lesions, tonsillar disease, prostatic disease, nasopharyngeal polyps, and various types of surgically nonresectable masses.
Acknowledgments
The authors reported that there were no conflicts of interest.
ABBREVIATIONS
| REAH | Respiratory epithelial adenomatoid hamartoma |
Footnotes
Coblator II, ArthroCare Corp, Austin, Tex.
Arista, Bard Davol Inc, Warwick, RI.
Monné Rodriquez JM, Cambi C, Pratesi A, et al. Feline mesenchymal nasal hamartoma in two siblings (abstr). J Comp Pathol 2018;158:122.
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