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==Description==
==Description==
Oesophageal neoplasia is very rare, accounting for less than 0.5% of all neoplasia in dogs. It has a higher incidence in the areas where ''Spirocerca lupi'', a [[Helminth|helminth parasite]], is endemic in Africa and the south-eastern USA. The most commonly reported forms of neoplasm are:
Oesophageal neoplasia is very rare, accounting for less than 0.5% of all neoplasia in dogs. It has a higher incidence in the areas where ''Spirocerca lupi'', a [[Helminths|helminth parasite]], is endemic in Africa and the south-eastern USA. The most commonly reported forms of neoplasm are:
*'''Squamous cell carcinoma''' - usually apparent as an annualar thickening in the middle third of the oesophagus, anterior to the heart base.
*'''Squamous cell carcinoma''' - usually apparent as an annualar thickening in the middle third of the oesophagus, anterior to the heart base.
*'''Leiomyosarcoma'''
*'''Leiomyosarcoma'''
===Diagnostic Imaging===
===Diagnostic Imaging===
====Radiography====
====Radiography====
Plain radiographs of the chest may show:
Plain radiographs of the chest may show a mass of soft tissue opacity associated with the oesophagus, although apparent masses in the caudal oesopahagus could also represent hiatal hernias. Some tumours (such as osteosarcomas) may contain areas of mineralisation. There may be intra-luminal gas retention or an oesopageal stricture with cranial dilation. It should be noted that there are numerous other causes of [[Oesopageal Stricture|oesophageal strictures]], including peri-oesophageal (thoracic) neoplasia and inflammatory lesions like abscesses and granulomata.
'''Barium contrast studies''' may be used to define mucosal irregularities and strictures whereas dynamic lesions, such as swallowing defects and regurgitation, can be assessed by '''fluoroscopy'''.
'''Barium contrast studies''' may be used to define mucosal irregularities and strictures whereas dynamic lesions, such as swallowing defects and regurgitation, can be assessed by '''fluoroscopy'''.
It may difficult to image the mass by '''ultrasonography''' but this technique may be useful if the mass lies in the cranial mediastinum or close to the diaphragm.
It may difficult to image the mass by '''ultrasonography''' but this technique may be useful if the mass lies in the cranial mediastinum or close to the diaphragm.
'''Endoscopy''' can allow direct visualisation of the mass if it extends into the oesophageal mucosa and lumen. Grab biopsies can also be taken via the endoscope.
'''Endoscopy''' can allow direct visualisation of the mass if it extends into the oesophageal mucosa and lumen. Grab biopsies can also be taken via the endoscope.
Only 3-5 cm of the length of the oesophageal can be resected without risking dehiscence of the anastomosis and it is advisable to restrain the patient in a headcollar and side-reins after the procedure to prevent this site from coming under tension. The oesophagus is especially prone to dehiscence because it is under constant tension (exacerbated by movement) and because it lacks a serosa which is responsible for the formation of an initial fibrin seal during healing of the rest of the gastro-intestinal tract. To support a large resection, intercostal muscle flaps, omentum or synthetic meshes can be wrapped around an anastomotic site. Tension on the oesophagus can also be released by sectioning the phrenico-oesophageal membrane (which attaches it to the diaphragm) or by making a circumferential incision through the outer longitudinal muscle layer. Dehiscence of a surgical wound is one cause of [[Rupture of the Oesophagus|oesophageal rupture]]. Bougeinage may be used to prevent the formation of [[Oesophageal Stricture|strictures]] at the surgical site. Gastrostomy tubes can be used for short-term palliation of cases with extensive tumours that have obliterated the oesophageal lumen.
Only 3-5 cm of the length of the oesophageal can be resected without risking dehiscence of the anastomosis and it is advisable to restrain the patient in a headcollar and side-reins after the procedure to prevent this site from coming under tension. The oesophagus is especially prone to dehiscence because it is under constant tension (exacerbated by movement) and because it lacks a serosa which is responsible for the formation of an initial fibrin seal during healing of the rest of the gastro-intestinal tract. To support a large resection, intercostal muscle flaps, omentum or synthetic meshes can be wrapped around an anastomotic site. Tension on the oesophagus can also be released by sectioning the phrenico-oesophageal membrane (which attaches it to the diaphragm) or by making a circumferential incision through the outer longitudinal muscle layer. Dehiscence of a surgical wound is one cause of [[Rupture of the Oesophagus|oesophageal rupture]]. Bougeinage may be used to prevent the formation of [[Oesophageal Stricture|strictures]] at the surgical site. Gastrostomy tubes can be used for short-term palliation of cases with extensive tumours that have obliterated the oesophageal lumen.
One study of 6 dogs that underwent partial oesophagectomy for treatment of ''S. lupi''-related oeophageal sarcomas reported a median survival of 267 days with adjunctive doxorubicin therapy. Another study of 4 dogs with oesophageal leiomyosarcoma reported potential long term resolution of clinical signs following surgical resection (despite incomplete margins) if the tumour was of a low histological grade (all those in the study were of grade 1).
One study of 6 dogs that underwent partial oesophagectomy for treatment of ''S. lupi''-related oeophageal sarcomas reported a median survival of 267 days with adjunctive doxorubicin therapy<ref>* Ranen E, Sharmier M. H, Shahar R. et al, (2004), '''Partial Esophagectomy with Single Layer Closure for Treatment of Oesophageal Sarcomas in 6 Dogs''', ''Vet Surg'' 33:428-434</ref>. Another study of 4 dogs with oesophageal leiomyosarcoma reported potential long term resolution of clinical signs following surgical resection (despite incomplete margins) if the tumour was of a low histological grade (all those in the study were of grade 1) <ref>Farese J.P, Bacon N.J et al, (2008), '''Oesophageal leiomyosarcoma in dogs: surgical management and clinical outcome of four cases''', ''Vet Comp Oncol'', Mar;6(1):31-8 </ref>.
===Chemotherapy===
===Chemotherapy===
This approach has rarely been reported except as an adjunctive therapy to the surgical removal of ''S. lupi''-associated masses, where '''doxorubicin''' was used post-operatively.
This approach has rarely been reported except as an adjunctive therapy to the surgical removal of ''S. lupi''-associated masses, where '''doxorubicin''' was used post-operatively <ref>1</ref>.
===Radiotherpy===
===Radiotherpy===
==References==
==References==
</references>
* Morris J, Dobson J (2001) Gastrointestinal Tract, in Small Animal Oncology, Blackwell Science, pp 125-127
* Morris J, Dobson J (2001) Gastrointestinal Tract, in Small Animal Oncology, Blackwell Science, pp 125-127
* Liptak J. M, Withrow S.J, (2007), Cancer of the Gastrointestinal Tract, in Withrow and MacEwen's Small Animal Clinical Oncology, fourth edition, Eds Withrow S.J, Vail D.M, Missouri, Saunders Elsevier, pp 477-478
* Liptak J. M, Withrow S.J, (2007), Cancer of the Gastrointestinal Tract, in Withrow and MacEwen's Small Animal Clinical Oncology, fourth edition, Eds Withrow S.J, Vail D.M, Missouri, Saunders Elsevier, pp 477-478
[[Category:Oesophagus_-_Pathology]]
[[Category:Oesophagus_-_Pathology]]
[[Category:To_Do_-_James]]
[[Category:To_Do_-_James]]
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