A highly malignant neoplasia that readily metastasizes to the medial iliac lymph nodes. May also lead to paraneoplastic hypercalcaemia due to parathyroid hormone-related peptide.
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A highly malignant neoplasia that readily metastasizes to the medial iliac lymph nodes. May also lead to paraneoplastic hypercalcaemia due to parathyroid hormone-related peptide. The tumours can be between 1 and 10cm in size and 50% of them will metastasize.
==Diagnosis==
==Diagnosis==
===History and Clinical Signs===
===History and Clinical Signs===
See [[Anal Sac Disease - General - WikiClinical|Anal Sac Disease - General]]
See [[Anal Sac Disease - General - WikiClinical|Anal Sac Disease - General]]
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Also:
Also:
*Flattened stools
*Flattened stools
*Pernieal swelling
*Pernieal swelling
*Hypercalcaemia signs including polydipsia and polyuria.
*Hypercalcaemia signs including polydipsia and polyuria.
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===Biochemistry===
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To assess:
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*Calcium
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*Phosphate
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*Renal function
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===Thoracic radiographs===
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At least two views to check for thoracic metastases.
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===Abdominal imaging===
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Caudal abdominal radiographs or abdominal ultrasound to assess the medial iliac lymph nodes for metastases.
==Treatment==
==Treatment==
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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.
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===Treatment of Hypercalcaemia===
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High fluid rates of 0.9% saline to diurese calcium. Furosemide should be administered (2mg/kg intravenously) once the patient in normocalcaemic.
==Prognosis==
==Prognosis==
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Potential postoperative complications include infection, wound dehiscence, faecal incontinence and in 25% of cases, local recurrence. Hypercalcaemia reoccurs in 35-50% of cases due to metastases. Serum calcium levels should therefore be reguarly along with evidence of mass regrowth. Post-op survival ranges between 2 and 39 months with the average being 8 months