Biologic Behavior

  • Esophageal tumors are very rare in both cats and dogs accounting for < 0.5% of all cancers
  • Female cats are predisposed, but no known breed or sex predisposition in dogs
  • Malignant tumors are more common and include SCC, leiomyosarcoma, FSA, and OSA
  • SCC is common in cats with the middle 3rd of the esophagus cranial to the thoracic inlet most commonly affected
  • Neuroendocrine carcinoma and adenosquamous carcinoma reported in cats
  • Sarcomas have been reported secondary to Spirocerca lupi infestation in indigenous areas such as Israel and SE USA
  • Spirocerca lupi-induced esophageal sarcomas include FSA, OSA, and undifferentiated sarcomas
  • Locally invasive with metastasis to regional lymph node via direct extension or lymphatic or hematogenous routes
  • Benign tumors include leiomyoma and solitary extramedullary plasmacytoma
  • Solitary extramedullary plasmacytoma have a predilection for the terminal esophagus and cardia
  • Paraesophageal (i.e., thymic, heart base, or thyroid) tumors can invade the esophagus
  • Pulmonary and mammary carcinoma can metastasize to the esophagus
  • Esophageal ADC is possibly associated with cholecystectomy in humans due to bile reflux


+ Clinical Signs

  • Non-specific and include debilitation, regurgitation, hematemesis, weight loss, dysphagia, pain during swallowing, and aspiration pneumonia
  • Regurgitation may be sporadic due to distensibility of esophagus and slowly progressive disease
  • Hypertrophic osteopathy has been reported especially with Spirocerca lupi­-induced esophageal sarcomas
  • Spirocerca lupi-induced esophageal sarcomas are also associated with esophageal granulomas, aortic scarring and mineralization, and spondylitis of the caudal thoracic vertebrae (T6-T12)
  • Esophageal tumors < 2 cm rarely cause clinical signs


+ Survey Radiographs

  • Survey radiograph findings include:
  • Gas retention within esophageal lumen
  • Esophageal dilation proximal to the mass
  • Soft tissue mass displacing the esophagus or extending into the lumen
  • Displacement of mediastinal structures
  • Lumen irregularities

+ Contrast Esophagram

  • Contrast esophagram can be performed ± fluoroscopy
  • Esophagram findings include filling defect, stricture, or intraluminal mass

+ Esophagoscopy

  • Esophagoscopy provides direct visualization of the mass and ability to collect biopsy samples
  • Malignant tumors are usually ulcerated
  • Leiomyoma appears as circumscribed submucosal mass movable beneath the mucosal layer
  • Several biopsies should be taken due to prominent inflammation and necrosis, but representative samples are difficult to collect
  • Iatrogenic perforation is rare with endoscopic biopsy

+ Other Diagnostic Techniques

  • Plasma cell tumors may cause hyperproteinemia, hypercalcemia, and monoclonal gammopathy
  • Fecal flotation test and examination for Spirocerca lupi ova
  • Open surgical biopsy via either exploratory thoracotomy or cervical exploration


+ General Considerations

Treatment is complicated as the majority of cases are advanced at the time of diagnosis

+ Surgery

  • Intrathoracic resection is difficult due to poor healing, large resection, anastomotic tension, and poor exposure
  • Distal esophagus can be reconstructed with gastric advancement through the diaphragm
  • Esophageal reconstruction has been reported with muscle flaps or microvascular transfer of colon or small intestine
  • Results of esophageal reconstruction are variable
  • En bloc esophageal resection is associated with excellent local control and > 50% long-term survival
  • Partial esophagectomy with primary esophageal closure has been reported in the management of 6 dogs with Spirocerca lupi-induced esophageal sarcomas with good postoperative recovery and function, and survival times ranging from 2 to > 20 months
  • Palliation with enteral nutrition (via E- or G-tubes) or self-expanding intraluminal stent

+ Radiation Therapy

  • Indications: tumors of the cervical esophagus
  • Intrathoracic esophageal tumors should not be irradiated due to poor radiation tolerance of the lungs and heart

+ Chemotherapy

  • Unknown
  • Doramectin (200 µg/kg q 2 weeks SC for 3 treatments) used successfully in dogs with Spirocerca lupi esophageal granulomas

+ Photodynamic Therapy

Photodynamic therapy using photofrin as a photosensitizer has been described in the management of 1 dog with esophageal SCC with PR and 9-month survival time

+ Prognosis

  • Prognosis is poor for malignant esophageal tumors due to difficult surgical resection and high metastatic rate
  • Prognosis is good for benign lesions following complete resection
  • 5-year survival rate is < 20% in humans using a combination of surgery, radiation therapy, and chemotherapy