Pulmonary lymphoma

From Dog

Pulmonary lymphoma is an uncommon form of neoplasm characterized by primary lung development.

Secondary pulmonary lymphoma are far more common in cases of canine lymphoma[1][2], primary cases have been reported.

Although primary pulmonary lymphomas are usually T-cell based, primary B-cell pulmonary lymphomas can also occur and are characterized by lymphomatoid granulomatosis[3]. This condition is characterized by multiple pulmonary nodules that consist of sheets of atypical lymphoreticular and plasmacytoid cells admixed with fewer mature eosinophils and lymphocytes[4].

Clinically affected dogs frequently present with gradual weight loss, intermittent anorexia, non-productive coughing, rhinitis and dyspnea[5].

Blood tests may reveal paraneoplastic hypercalcemia[6].

Diagnosis is usually based on radiographic, echocardiographic and CT imaging studies which usually show multiple or discrete pulmonary masses with mineralization[7], variable degrees of tracheobronchial lymphadenopathy[8], pleural effusion[9] and cardiomegaly.

A definitive diagnosis requires histological examination of ultrasound-guided biopsy or surgical biopsies.

A differential diagnosis would include heartworm disease, pulmonary interstitial fibrosis, primary heart diseases, histiocytoma, pulmonary carcinoma and bronchial carcinoma

Treatment is usually reserved to lobectomy in cases where an individual mass is identified, but most cases require chemotherapy (e.g. L-asparaginase, cyclophosphamide, doxorubicin, lomustine)[10].

Adjunct therapy with radiation or in terminal cases, palliative anti-inflamamtory drugs such as prednisolone have also been reported.

Prinary T-cell lymphomas and evidence of anterior pulmonary lymphadenopathy are usually associated with poorer survival in dogs[11].

References

  1. Snyder JM et al (2008) Secondary intracranial neoplasia in the dog: 177 cases (1986-2003). J Vet Intern Med 22(1):172-177
  2. Foster AP et al (1997) Cutaneous T-cell lymphoma with Sézary syndrome in a dog. Vet Clin Pathol 26(4):188-192
  3. Park HM et al (2007) Pulmonary lymphomatoid granulomatosis in a dog: evidence of immunophenotypic diversity and relationship to human pulmonary lymphomatoid granulomatosis and pulmonary Hodgkin's disease. Vet Pathol 44(6):921-923
  4. Lucke VM et al (1979) A lymphomatoid granulomatosis of the lungs in young dogs. Vet Pathol 16:405–412
  5. Leach LM & Van Camp SL (2010) What is your diagnosis? Pulmonary lymphosarcoma in a dog. J Am Vet Med Assoc 236(8):827-828
  6. Bergman PJ (2012) Paraneoplastic hypercalcemia. Top Companion Anim Med 27(4):156-158
  7. Day MJ et al (1996) Lesions associated with mineral deposition in the lymph node and lung of the dog. Vet Pathol 33(1):29-42
  8. Jones BG & Pollard RE (2012) Relationship between radiographic evidence of tracheobronchial lymph node enlargement and definitive or presumptive diagnosis. Vet Radiol Ultrasound 53(5):486-491
  9. Geyer NE et al (2010) Radiographic appearance of confirmed pulmonary lymphoma in cats and dogs. Vet Radiol Ultrasound 51(4):386-390
  10. Hatoya S et al (2011) Successful management with CHOP for pulmonary lymphomatoid granulomatosis in a dog. J Vet Med Sci 73(4):527-530
  11. Starrak GS et al (1997) Correlation between thoracic radiographic changes and remission/survival duration in 270 dogs with lymphosarcoma. Vet Radiol Ultrasound 38(6):411-418