Spleen - Pathology

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()Map\Tab LYMPHORETICULAR & HAEMATOPOIETIC SYSTEM (Map/Tab)
SECONDARY LYMPHOID SYSTEM



NB:Be aware of age-related changes regarding the spleen

Anatomy & Physiology

See here

Splenic Lesions

  • splenomegaly is the main clinical finding associated with the spleen in disease

Splenitis

Anthrax

Torsion

Haemolytic Anaemia

Chronic Venous Congestion

  • this may be seen along with chronic venous congestion of the liver in cases of chronic cardiac failure

Barbituates

  • administration of barbituates can produce a degree of splenomegaly due to splenic engorgement by erythrocytes

Splenic Tumours

  • these are important surgically since splenomegaly can be diagnoses clinically by palpation or X-ray and some are surgically curable

Hyperplastic Nodules or Benign Lymphoma

  • very common incidental findings in older dogs
  • should not be mistakenly identified as pathognomic lesions
  • 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
  • infrequently, may rupture and give rise to haemorrhage

Haemangioma

  • benign tumour of dogs
  • may grow to considerable size
- the size of the lesion giving rise to clinical signs is compounded by haemorrhage from and into the tumour
- thus, a large mass of apple size may be found protruding from the spleen and adherent to the omentum
  • on section, it is largely blood clot
  • responds well to surgery
- therefore it must be distinguished from haemangiosarcoma

Haemangiosarcoma

  • highly malignant tumour of dogs
  • distinguished from the superficially similar haemangioma by the presence of much more formed, solid tumour tissue
  • accurate prognosis demands histological examination
  • secondaries are common locally in the omentum and in the liver
- course is usually short, often only a month or two
- metastases may occur in almost every organ

Haematopoietic Neoplasms

lymphosarcoma
  • splenomegaly occurs in multicentric lymphosarcoma
  • splenic enlargement may be marked if any form of lymphosarcoma is in leukaemic phase
myeloid (granulocytic) leukaemia
  • rare
  • all species
  • extreme form with spleen approaching liver size
systemic mastocytosis
  • cat
  • extreme form with spleen approaching liver size

Infarction

Rupture