Changes

Tumours of the anal sac can be detected by digital rectal palpation of the anal sac and assosiated structures, this must be performed with care as frequently the tumours are small and unilateral. Best carried out under general anaesthetic with manual compression of the caudal abdomen towards the rectum.

Tumours of the anal sac can be detected by digital rectal palpation of the anal sac and assosiated structures, this must be performed with care as frequently the tumours are small and unilateral. Best carried out under general anaesthetic with manual compression of the caudal abdomen towards the rectum.

===Biochemistry===

===Laboratory Tests===

*Calcium

*Calcium

*Phosphate

*Phosphate

*Renal function

*Renal function

===Thoracic radiographs===

===Radiography===

==Thoracic Radiography==

At least two views to check for thoracic metastases.  

At least two views to check for thoracic metastases.  

===Abdominal imaging===

==Abdominal imaging==

Caudal lateral abdominal radiographs or abdominal ultrasound to assess the medial iliac lymph nodes for metastases. When enlarged they  displace the rectum ventrally.  

Caudal lateral abdominal radiographs or abdominal ultrasound to assess the medial iliac lymph nodes for metastases. When enlarged they  displace the rectum ventrally.  

Sites of metastasis include the liver, spleen, abdominal lymph nodes and the lungs.  

Sites of metastasis include the liver, spleen, abdominal lymph nodes and the lungs.  

===Needle biopsy and Histopathology===

===Biopsy===

Guided by ultrasound to aspirate the effected lymph nodes.

Ultrasound guided needle biopsy to aspirate the effected lymph nodes.

==Treatment==

==Treatment==

The treatment of choice is surgical excision if the patient is normocalcaemic without any metastases. The success will depend upon the size of the mass.  

The treatment of choice is surgical excision if the patient is normocalcaemic without any metastases. The success will depend upon the size of the mass.