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Thymoma

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Thymoma By L.Jamal 5 & 10 year survival Type A - 100% and 95%, respectively Type AB - 93% and 90%, respectively Type B1 - 89% and 85%, respectively Type ... – PowerPoint PPT presentation

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Title: Thymoma


1
Thymoma By L.Jamal
2
The Thymus
  • The thymus is a specialized organ of the immune
    system .
  • It is located in the ant. mediastinum .
  • Production of T- Lymphocytes .

3
The Thymus
  • A pyramid shaped organ , pinkish grey in colour
    with a soft and lobulated surface .
  • 5 cm in length , 4 cm in breadth and 6mm in
    thickness.
  • Wieghs 20-35 grams during puberty and regresses
    to 6 gr in adulthood .

4
Structure
  • 2 lobes , each lobe is composed of multiple
    lobules and sorrounded in a capsule .
  • Each lobule consists of multiple follicle.
  • Each follicle is divided into a capsule and
    medulla .

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  • Cortex contains thymocytes ? T- lymphocytes.
  • Medulla contains corpuscles (area of
    maturation) .

10
Vasculature
  • Internal mammary , superior and inferior thyroid
    arteries .
  • The veins end in the left brachiocephalic vein
    (innominate vein), and in the thyroid veins .

11
Mediastinal Masses
  • Thymoma .
  • Lymphoma .
  • Germ cell tumor .
  • Thyroid an Parathyroid tumors .

12
Thymoma
  • A neoplasm of the Thymic epithelial cells .
  • Results from dysregualtion of the proliferation
    and maturation of T- lymphocytes .
  • This process results in either Autoimmunity or
    Immune defeciency .

13
  • As a result , thymomas are associated with
    autoimmune diseases in 70 of the patients
    during diagnosis .
  • Thymomas are ussually encapsulated and spread by
    local extension .

14
Epidemiology
  • Primary tumors of the mediastinum represent 3 of
    all chest tumors .
  • Primary anterior mediastinal masses account for
    50 .
  • 45 are thymomas .

15
  • FM ? 1 1 .
  • Thymomas in the pediatric age group tend to run
    an aggressive course .

16
Clinical Presentation
  • 30 local symptoms .
  • 30 abnormal chest radiographs .
  • 30 Myasthenia Gravis (paraneoplastic syndrome).

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  • Local symptoms
  • Dyspnea .
  • Dyspahgea .
  • Cough .
  • SVC obstruction .
  • Thymomas tend to be highly vascular ? bleeding
    and necrosis .

19
  • Paraneoplastic
  • MG.
  • Hypogammaglobulenemia .
  • Good syndrome .
  • Oppurtunistic infections .

20
Work up
  • Blood
  • CBC Anaemia , thrombocytopenia ,
    agranulocytosis .
  • Quantitative Ig studies ? Panhypogammaobulinenmia
    .
  • CD4 T-cell count .
  • Pre an post vaccination antibody levels .

21
  • Radiology
  • Chest x ray .
  • CT or MRI .
  • Nuclear imaging ( octreotide scan )

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  • Tissue sampling
  • Core biopsies .
  • FNA .
  • Limited sternotomy
  • Mediastinoscopy .

26
Histologic Findings
  • Mixed epithelial and lymphoid cells .
  • 4 categories
  • Spindle cell predominant .
  • Lymphocyte predominant .
  • Mixed .
  • Epithelial predominant .

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  • WHO classification
  • A Spindle or Oval cells .
  • B dendredtic or epitheloid .
  • AB mixed .
  • C resembles other organs .
  • Types A , AB ? benign .
  • Type B , C ? malignant .

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Staging
  • Masaoka Staging system .
  • I Macrospcopically encapsulate , no capsular
    invasion .
  • II Macroscopic invasion to surrounding tissue or
    microscopic capsular invasion .
  • III Macroscopic invasion into neighboring
    organs.
  • IVa Pleural or pericardial dissemination.
  • IVb Lymphogenous or hematogenous metastases

30
TTT
  • Surgical and medical .
  • Thymectomy is curative in the early stages .
  • It can be challenging .
  • Thymectomy releaves obstructive symptoms and
    improves paraneoplastic symptoms .

31
  • Hypogammaglobulinemia shows no improvement after
    thymectomy and requires monthly Ig infusions .
  • MG patients show a 25 improvement in mw after
    thymectomy .

32
  • Radiotherapy unresectable tumors post sugical
    resection .
  • Primary radiotherapy for stages III IVa
    improved the 5y survival 40-50 .
  • Chemotherapy for stages IV a , b using
    Cisplatin , Vincristine Doxyrubicin .

33
Prognosis
  • Adverse predictive factors
  • Invasive tumor .
  • Tracheal compression .
  • Young age .
  • Tumor more than 8 cm .

34
5 10 year survival
  • Type A - 100 and 95, respectively
  • Type AB - 93 and 90, respectively
  • Type B1 - 89 and 85, respectively
  • Type B2 - 82 and 71, respectively
  • Type B3 - 71 and 40, respectively
  • Type C - 23 (5-year survival rate)

35
Thymic Hyperplasia
  • Increase in the size of the gland with normal
    microscopic arrangement .
  • Rare intety .
  • Presentation is similar to a thymoma .

36
  • 3 subtypes
  • Massive thymic hyperplasia .
  • Common in infancy presents with compressive
    symptoms .
  • Thymic hyperplasia assocaited with endocrine
    abnormalities .

37
  • Rebound thymic hyperplasia
  • The thymus gland regresses in size during times
    of severe stress then enlargres beyond normal .
  • Seen following , severe burns , pneumonia ,
    tuberculosis and malignancies .

38
  • Management
  • Close monitoring for 2 years .
  • If thymic hyperplasia doesn't regress by 2 years
    , biopsies and resection are warranted .

rs
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Thymic rebound hyperplasia in an 11-year-old girl
with Hodgkin lymphoma.
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