B21 Disorders that effect the spleen and thymus

Question 1

Sources of Massive Splenomegaly

Answer 1

Cause spleen to be more than 1 Kg.

1. Chronic myeloproliferative disorders:
   
   • CML
   • Chronic Myelofibrosis
   • Polycythemia Vera
   • Essential thrombocytemia
2. CLL
3. Hairy cell leukemia
4. Lymphoma
5. Malaria
6. Gaucher disease
7. Primary splenic tumors

Question 2

Sources of moderate/medium splenomegaly

Answer 2

Spleen is between 500gm and 1 kG

1. Acute leukemia, AML or ALL
2. Hereditary spherocytosis
3. Thalassemia major
4. Autoimmune hemolytic anemia
5. Chronic congesitve splenomegaly
6. Amyloidosis
7. Neimann-pick disease
8. Langerhans histiocytosis, multisystemic
9. Chronic splenitis
10. Miliary TB, sarcoidosis
11. Metastatic carcinoma or sarcoma

Question 3

Sources of mild splenomegaly

Answer 3

Spleen is above normal (150g) and less than 500g.

1. Acute splenitis
2. Scute splenic congestion
3. Infectious mononucleosis
4. Acute febrile disorders

Question 4

Disorders that affect the thymus

Answer 4

Thymic hyperplasia:

• Thymus will contain lymphoid follicles and germinal centers in the medulla
• Contains reactive B cells.
• Caused by autoimmune disorders: SLE, RA, Myasthenia Gravis.
• Thymectomy may be beneficial in autoimmune diseases

Thymoma:

• Tumor of neoplastic thymic epithelial cells, with non-neoplastic thymocytes, pre-T cells.
• Benign, encapsulated form
• Type 1 malignant: cytologically benign but locally invasive
• Type 2, malignant thymic carcinoma, cytologically malignant and metastatic.
• Thymus tumors are rare, occur in mid-aged adults, and often cause an associated myasthenia gravis, which will halt one the thymoma is removed.

Question 5

Other disorders of the spleen

Answer 5

Hypersplenism, due to an elarged or congested spleen, removing excessive blood cells.

Ruptured spleen - swollen spleen plus trauma, or due to extreme acute splenomegaly, a life threatening emergency due to bleeding.

Splenectomy - increases risk of infection by capsulated microbes.