This presentation on the presentation, work up, management of thymoma focusing on latest guide lines. It enamurates the clinical suspicious, age of presentation, differential diagnosis and treatment.

1. Thymic Carcinoma
Dr Iqra Iftikhar
PGR RADIATION ONCOLOGY
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2. Presentation layout
o Introduction
o Inmol data
o Anatomy
o Presentation
o Types
o Workup
o Staging
o Treatment
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3. Introduction
o Adults aged 40 to 60.
o 20% of all mediastinal tumors but 50% anterior mediastinal
tumors.
o Thymic carcinomas represent less than 1% of thymic tumors.
o No known etiologic factors
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4. Inmol Data
2022 1 7210 0.013%
2021 5 7174 0.06%
2020 7 5743 0.12%
2019 1 7365 0.013%
2018 2 5877 0.03%
2017 1 5296 0.018%
2016 1 5481 0.018%
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5. Presentation layout
o Introduction
o Inmol data
o Anatomy
o Presentation
o Types
o Workup
o Staging
o Treatment
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6. ANATOMY
o Thymus is an anterior mediastinal structure
o Responsible for the maturation of T-cells.
o Lymphatic drainage is to the
o Lower cervical,
o Internal mammary,
o Hilar nodes.
o Thymus consists of
o Capsule
o Cortex,
o Medulla.
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7. o Histologically, it includes
o Epithelial cells,
o Epithelioreticular cells (form Hassall’s corpuscles),
o Myoid cells,
o Early T lymphocytes (“thymocytes”),
o B Lymphocytes
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9. • IHC Markers of Thymic carcinoma
• CD 20+ intratumoral B Lymphocyte
• CD57+
• CD5+
• Tdt+ T cells
• CK+
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10. Presentation layout
o Introduction
o Inmol data
o Anatomy
oPresentation
o Types
o Workup
o Staging
o Treatment
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11. Presentation
o Often incidental finding on imaging.
o Local symptoms due to mass effect
o Chest pain,
o Dyspnea,
o Cough,
o Phrenic nerve palsy,
o SVC syndrome.
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12. o Para neoplastic syndromes prior to or after diagnosis.
o Up to 50% of patients will present with Myasthenia Gravis;
o It is less common for MG patients to have associated thymoma.
o Other less common Para neoplastic syndromes
o Red cell aplasia,
o Immunodeficiency,
o Multiorgan autoimmunity.
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13. Differentials Mediastinal mass
Non-neoplastic conditions
• intrathoracic goiter,
• thymic cysts,
• lymphangiomas,
• lymphangiomas Masses in the anterior mediastinum can be Non-neoplastic conditions
• Non-neoplastic conditions
• ,
• lymphomas,
• Non-neoplastic conditions
• ,
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Non-neoplastic conditions Neoplastic conditions
intrathoracic goiter,
Non-neoplasticconditions Neoplastic conditions
Intrathoracic goiter Lymphomas
Thymic cysts Thymic carcinoids
Lymphangiomas Thymolipomas
Thymic carcinomas
Germ cell tumors
Lung mets

14. Thymoma Thymic carcinoma
Cells resemble non cancerous thymic cells
Myasthenia Gravis 10-80%
Cells different from normal thymic cells
No association with MG
Grows slowly
Rarely undergo metastasis
Grow rapidly
Significant metastasis
CD5, CD 70, CD117 Expression epithelial cells not seen CD5, CD 70, CD117 Expression epithelial cells 60%
Long survival due to indolent course
More common
Short survival progressive disease
Less common
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15. Thymic Carcinoma Subtypes
• • Squamous carcinomas
• Squamous cell carcinoma, NOS
• Basaloid carcinoma
• Lymphoepithelial carcinoma
• • Adenocarcinomas
• Adenocarcinoma, NOS
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Squamous carcinomas Adenocarcinomas Mucoepidermoid carcinoma
Squamous cell carcinoma, NOS Adenocarcinoma, NOS Clear cell carcinoma
Basaloid carcinoma Low grade papillary
adenocarcinoma
Sarcomatoid carcinoma
Lymphoepithelial carcinoma Thymic carcinoma with adenoid
cystic carcinoma-like features
Carcinosarcoma
Adenocarcinoma, enteric-type
Adenosquamous carcinoma

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21. Presentation layout
o Introduction
o Inmol data
o Anatomy
o Presentation
o Types
o Workup
o Staging
o Treatment
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22. WORK UP
o H&P.
o If thymoma suspected and considered resectable, biopsy may
be omitted and resection performed.
o If unresectable/inoperable, core needle biopsy to confirm
diagnosis
o (open biopsy also possible; biopsy should not violate pleural
space);
o Multidisciplinary evaluation indicated.
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23. o Serum b-hCG and AFP (rule out germ cell tumor),
o CBC, CMP, serum level of anti-Ach antibodies to assess for MG.
o Imaging:
o Chest CT with contrast,
o PET/CT (optional),
o PFTs.
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24. Presentation layout
o Introduction
o Inmol data
o Anatomy
o Presentation
o Types
o Workup
oStaging
o Treatment
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25. Modified Masaoka clinical staging Thymoma
o STAGE I
o Macro + microscopically completely encapsulated
o STAGE II
o II A Microscopic transcapsular invasion
o II B Macroscopic invasion fatty tissue
o Adherent to but not through mediastinal pleura or pericardium
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26. o STAGE III
o Macroscopic invasion adjacent organs ( pericardium , lung)
o III A Without invasion great vessel
o III B With invasion great vessel
o STAGE IV
o Pleural pericardial dissemination
o Lymphogenous or hemetogenous mets
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27. Thymic carcinomas TNM
o Tx
o Tumor cannot be assessed
o T0
o No tumor
o T1
o Tumor encapsulated
o Extend mediastinal fat
o T1a Mediastinal pleura not involved
o T1b Mediastinal pleura involved
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28. o T2
o Direct invasion pericardium
o T3
o Direct invasion lung , brachiocephalic , phrenic nerve , chest wall,
extra pericardial pulmonary artery and vein
o T4
o Invasion, aorta , arch vessel, trachea, oesophagus, myocardium ,
intrapericardial pul artery
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29. o N0
o No nodes
o N1
o Anterior Perithymic nodes +
o N2
o Deep intrathoracic and cervical nodes +
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30. o M0
o No mets
o M1
o Mets pleura, pericardium , distant mets
o M1a separate pleural pericardial nodes
o M1b pulmonary intrapericardial nodes or distant mets
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31. Presentation layout
o Introduction
o Inmol data
o Anatomy
o Presentation
o Types
o Workup
o Staging
oTreatment
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32. TREATMENT
oSurgery:
o Total thymectomy with negative
margins is mainstay of therapy in
resectable cases.
o This is typically performed with
median sternotomy.
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33. o Resection of both phrenic nerves should be avoided to prevent severe
respiratory compromise.
o Signs and symptoms of MG should be controlled medically with
anticholinesterase inhibitors prior to surgery.
o Thoracic surgeons with experience in managing thymomas and thymic
carcinomas.
o Stage ≥ II cases should be discussed and evaluated by a multidisciplinary
team.
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o Surgical biopsy should be avoided if a resectable thymoma
o Substantial potential of tumor seeding when the tumor capsule is
violated.
o Biopsy of a possible thymoma should avoid a transpleural
approach because of the substantial risk of converting a stage I
thymoma to a stage IV thymoma by spreading tumor within the
pleural space.
o Prior to surgery, patients should be evaluated for signs and
symptoms of myasthenia gravis and should be medically controlled
prior to undergoing surgical resection.

35. o Complete resection may require the resection of adjacent structures, including
the pericardium, phrenic nerve, pleura, lung, and even major vascular
structures.
o Surgical clips should be placed at the time of resection to areas of close margins,
residual disease, or tumor adhesion to unresected normal structures to help
guide accurate RT when indicated.
o During thymectomy, the pleural surfaces should be examined for pleural
metastases.
o If feasible, resection of pleural metastases to achieve complete gross resection.
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36. CHEMOTHERAPY
o Platinum-based CHT is indicated for thymic carcinoma,
o Unresectable disease, medically inoperable with gross disease.
o Downstaging and postoperatively based on degree of resection.
o For diffuse metastases, consider CHT alone.
o No randomized trials have identified superior regimen.
o Common regimens include
o cyclophosphamide/adriamycin/cisplatin (CAP),
o cisplatin/etoposide (PE), or
o carboplatin/paclitaxel.
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39. RADIATION
o Indications:
o PORT should be offered for positive surgical margins,
o stage III disease and considered for any thymic carcinoma.
o Dose:
o RT dosing is based on degree of resection with
o 45 to 54 Gy, for R0
o 55 to 60 Gy, for R1
o 60 to 70 Gy for R2,
o Definitive RT indicated for medically inoperable disease, with the addition of CHT and
its sequencing empiric.
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40. Radiation Dose
o Unresectable disease.
o 60 to 70 Gy
o • For adjuvant treatment,
o 45 to 50 Gy for clear/close margins
o 54 Gy for microscopically positive resection margins.
o 60–70 Gy gross residual disease (similar to patients with unresectable disease),when conventional
fractionation is applied.
o Palliative setting,
o 8 Gy in a single fraction,
o 20 Gy in 5 fractions,
o 30 GY in 10 fractions
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42. Radiation volume
o GTV
o Any grossly visible tumor. Surgical clips indicative of gross residual tumor should be included for
postoperative adjuvant RT.
o CTV for postoperative RT
o Entire thymus (for partial resection cases), surgical clips, and any potential sites with residual disease.
The CTV should be reviewed with the thoracic surgeon.
o Extensive elective nodal irradiation (ENI) (entire mediastinum and bilateral
Supraclavicular nodal regions) is not recommended, as thymomas do not commonly metastasize to
regional lymph nodes.
o PTV should consider the target motion and daily setup error.
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43. o The PTV margin should be based on the
o individual patient’s motion,
o simulation techniques used (with and without inclusion
motion),
o reproducibility of daily setup of each clinic
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44. OAR Tolerance Dose
Heart
Thyroid
Mean < 26 Gy
V45< 100%
Lung
Esophagus
V 20 < 30%
MEAN < 34%
V50 < 40%
Spinal Cord
TMJ
Parotid
Dmax < 50Gy
V60 < 60%
B/L MEAN < 25 Gy
U/L MEAN < 30-32 Gy
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45. Toxicity related to CHT
o Nephrotoxicity
o Haemorrhagic cystitis
o Cardiotoxicity
o Neuropathy
o Myalgia
o Secondary malignancy
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46. Toxicity related to RT
o Acute:
o Fatigue,
o Cough,
o Skin erythema.
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47. oLate:
o Hypothyroidism,
o Second malignancy
o Cardiac morbidity
o Radiation fibrosis
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48. Follow up
Thymoma Thymic Carcinoma
6 monthly H & P
CT CHEST with contrast for 2 years
than annually for 10 years
6 monthly H & P
CT CHEST with contrast for 2 years
than annually for 5 years
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49. Survival rates
Thymoma
10 year overall survival
Thymic carcinoma
5 year overall survival
Stage I 90% Stage I – II 91%
Stage II 70%
Stage III – IV 90% ( 5 Yr OS with complete
resection)
Stage III – IV 31%
( even with complete resection)
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50. Case Summary
o ABC 49y/F known MG patient since 2007, resident Lahore
presented with
o C/O
o Muscle weakness
o Slurred speech
o 2/9/21 CT CAP
o Large mediastinal mass 8.4 x 5.1 x 5.9cm
o Encasement left brachiocephalic vein with narrowing
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51. o Encasement left subclavian and carotid vessel
o No visceral mets
o T4 N0 M0
o Stage IIIB
o 16/4/21 Mediastinal mass biopsy
o THYMOMA
o Tdt+ Tcells
o CK+
o KI67 High PI
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52. o PLAN
o 3DCRT 60Gy/30fx to mediastinal mass
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