CYSTIC METASTASTIC LYMPH NODE IN A DOG WITH A SUBCUTANEOUS MAST CELL TUMOUR

Type:
Case Report
Topic:
Oncology
Companies:
(1) Hospital for Small Animals, Radiotherapy Department, The Royal (Dick) School of Veterinary Studies and The Roslin Institute, The University of Edinburgh, Easter Bush, Edinburgh, UK.
(2) Department of Veterinary Medicine, Veterinary Teaching Hospital, University of Milan, Radiology Department, Milan, Italy.
(3) Easter Bush Pathology, The Royal (Dick) School of Veterinary Studies and The Roslin Institute, The University of Edinburgh, Easter Bush, Edinburgh, UK.
Authors:
Isabel Del Portillo Miguel (1)
Maurizio Longo (2)
Magdalena Parys (1)
Paola Cazzini (3)
Juan Carlos Serra Varela (1)
Paper:
RESUMEN CORTO - SHORT SUMMARY

INTRODUCTION The prevalence of cyst-like lymph nodes is low in veterinary medicine. While in human medicine, these are mainly seen in head and neck cancers, in dogs, these can be found in non-cancerous and cancerous conditions, including different types of mesenchymal and epithelial neoplasia. This is the first case report describing a cystic metastatic lymph node in a dog with a subcutaneous mast cell tumour.

MATHERIAL AND METHODS A 9 year-old male neutered Lhasa Apso was referred to the Hospital for Small Animal, University of Edinburgh for staging after cytological diagnosis of a poorly differentiated subcutaneous mast cell tumour (MCT) in area of the right flank.

RESULTS An abdominal ultrasound revealed cranial to the aortic trifurcation, a severely enlarged rounded well-defined (4 cm in diameter), hypoechoic lesion in the region of the right medial iliac lymph node associated with marked perinodal steatitis. A CT scan performed for radiotherapy planning confirmed a large well-defined, rounded, non-enhancing hypoattenuating cystic mass in the area of right medial iliac lymph node, (HU=18). 

Fine-needle aspirates taken from the mass yielded, numerous poorly granulated mast cells with moderate anisocytosis and anisokaryosis, and few binucleated cells. A heterogeneous population of lymphocytes and few eosinophils and haemosiderin laden macrophages were also present, consistent with a diagnosis of lymph node with MCT metastasis.

CONCLUSION   Cystic-like lymph nodes in dogs diagnosed with mast cell tumours may indicate metastatic infiltration and this should be included in the differential diagnosis when present.  

 



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