Faecal Occult Blood Test

Case of the Month (Emma Scurrell February 2011)

A tonsillar squamous cell carcinoma in a 6 year old male Cocker Spaniel

The following are H&E sections from a tonsillar mass and an enlarged ipsilateral retropharyngeal lymph node.


 Fig 1. An H&E section from the tonsil: the tonsil is infiltrated and effaced by nests and interconnecting islands of neoplastic squamous epithelial cells which display occasional keratin pearl formation (arrow).


Fig 2. An H&E section of the retropharyngeal lymph node: the subcapsular cortex and sinuses are extensively infiltrated by a similar neoplastic infiltrate as to that present in the tonsil.

 

Fig 3. A higher magnification of the neoplastic infiltrate in the lymph node confirming metastatic squamous cell carcinoma.






Final Diagnosis

Tonsillar squamous cell carcinoma with metastasis to the retropharyngeal lymph node

Discussion

Squamous cell carcinomas affecting the tonsil typically arise from the tonsillar fossa epithelium.  The majority of tonsillar squamous cell carcinomas metastasise early with spread to the regional lymph nodes and distant sites including lungs, liver, kidneys, spleen and bone. The retropharyngeal lymph nodes are typically first affected, followed by parotid, submandibular and prescapular lymph nodes in the later stages. Because of their large size, metastatic lesions are often mistaken for the primary tumour and therefore it is important to check the oral cavity (paying particular attention to the tonsils) when a squamous cell carcinoma is diagnosed in the neck region of a dog for example.

Previous Monthly Cases

Hypertensive Retinopathy January 2010
FIP in a cat - uncommon presentation February 2010
Phaeohyphomycosis    March 2010 
Scleral Rupture April 2010
Canine and feline epulides May 2010
Erythema multiforme in a labrador retreiver June 2010
Keloidal fibrosarcoma in a labrador retreiver July 2010
Cutaneous epitheliotropic lymphoma  August 2010 
Benign cutaneous histiocytoma  September 2010 
Iridociliary adenoma October 2010
Proliferative thrombovascular necrosis of the pinnae November 2010
Signet-ring cell carcinoma in the stomach of a dog December 2010
Cutaneous infiltrative lipoma in a labrador January 2011






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Faecal Occult Blood Test