Splenic Neoplasms

Introduction

Splenic Neoplasms and benign hyperplasia are consideration once splenomegaly has been detected clinically by palpation or following radiography - some splenic neoplasias are surgically curable.

Hyperplastic Nodules or Benign Lymphoma

These are a very common incidental findings in older dogs that can occasionally be mistakenly for malignant masses. They consist of nodules of hyperplastic white and red pulp

- usually 1-2 cms in size, but occasionally may be larger

- spherical

- protrude hemispherically from the surface as yellow and red mottled nodules

Rarely these nodules may rupture and give rise to haemorrhage.

Haemangiosarcoma

Haemangiosarcomas are a highly malignant tumour of vascular endothelial origin (cf Haemangiomas which are more benign and generally affect other vascular tissue such as cutaneous vascular tissues). They commonly affect dogs and the most frequently affected areas are the spleen, pericardium, right atrium, liver and muscle. Cats are less frequently affected; the most common sites for feline haemangiosarcomas are the liver, spleen and mesentry. Metastasis occurs via the haematogenous route or via splenic capsule rupture and transabdominal spread. Metastatic sites include, lungs, liver, omentum and diaphragm. Surgery is the treatment of choice but even with this survival time remains very short.

Haematopoietic Neoplasms

Myeloid (Granulocytic) Leukaemia

• rare
• all species
• extreme form with spleen approaching liver size

Systemic Mastocytosis

• cat
• extreme form with spleen approaching liver size