A description of role of surgery for thymic diseases and myasthenia gravis within the frame of multimodality therapy. Categorical description of evolution of different techniques and classification of various types of thymic surgeries with an emphasis on thymoma.

1. Thymic Disorders- Clinical
Implications & Management
Considerations
Dr ROHAN REDDY C
Dept of Thoracic Surgery
MSMC, Narayana Health City

2. TOPICS OF DISCUSSION
• Thymus – the basics
• Spectrum of Thymic disorders & Clinical Implications
• Thymoma – Presentation, Classification, Clinical spectrum
• Surgery for Non-Thymomatous MG
• Surgery for Thymoma
• Adjuvant Modalities
• Rx for advanced cases

3. INTRODUCTION
• First being described as such by Galen of Pergamum (130 –200 AD)
• Etymology –
• Thymus from the Latin derivation “warty excrescence”
• Originally from Greek word - thymos,
• Meaning “soul” or “spirit,” as it was misrepresented as the seat of the soul by
the ancient Greeks
Thymus has remained an “organ of mystery” throughout the 2000-year
history of medicine

4. ANATOMY
• One of the primary lymphoid organs.
• Encapsulated, soft, bilobed organ
• Two lobes joined in midline by connective
• Merges with the capsule of each lobe.
• Max size early part of life
• Particularly around puberty
• Persists actively into old age
• Considerable fibrofatty degeneration
• Hides existence of thymic tissue.

5. EMBRYOLOGY
• Arises bilaterally from the 3rd & 4th
branchial pouches
• Elements from all 3 germinal layers
• Development - begins in 6th gest week.
• Migration - 8th week; leading to a fusion
of the bilateral lobes
• Final position in the antero-superior
mediastinum.

6. EMBRYOLOGY
• 9th gest week - purely epithelial.
• 10th wk - small lymphoid cells (fetal liver & BM;
lobulation of gland.
• 14-16 wks – Diff into Cortex & Medulla
• Rapid growth thereafter
• Greatest weight before birth (≈15 g)
• Ectopic thymic tissue/ ectopic thymoma
anywhere along this pathway.

7. ANATOMY
• Thymic lobes - loose fibrous connective tissue
capsule
• Septa penetrate to the junction of the cortex &
medulla
• Partially separate the irregular lobules
• Connective tissue septa - route of entry & exit for
blood vessels and nerves
• Carry efferent lymphatics.
• Most migrant cells enter or leave the thymus by
this route.

8. CORTEX
• Mainly - Lymphocytes, supported by network of
finely-branched epithelial reticular cells.
• Rich Capillary plexus
• Superficial subcapsular cortex & Main cortex
MEDULLA
• Network of reticular cells - coarser than in
the cortex
• Lymphoid cells - relatively fewer
• Fewer cells
• Central medulla of both thymic lobes -
continuous from one lobule to the next.
• Hassall’s corpuscles

9. HASSALL’S CORPUSCLES
• Characteristic finding in Thymus
• Central mass - consists one or more granular
cells
• Capsule - concentrically arranged
eosinophilic reticular epithelioid cells.
• Size - 20 - 100μm; tend to grow larger with
age.
• Function – not clear; autoimmune regulator
function

10. EPITHELIAL FRAMEWORK
• Thymus – network of interconnected epithelial cells.
• Intercellular desmosomal attachments
• Appropriate microenvironment of cell–cell contact
• Release of paracrine factors
• Thymic lymphocytes (T cells) develop and mature.
• Vary in size & shape as per positions in the thymus.
• Subcapsular cells: Blood- Thymus Barrier
• Medullary epithelial cells tend to form more solid cords
as well as thymic or Hassall’s corpuscles.
• Myoid cells – responsible for Autoimmunity in MG
• Several other cellular elements – connected to
autoimmune process elaboration.

11. ASSOCIATED
MEDICAL
CONDITIONS
MG affects – 1/3rd – 1/2 of all thymoma patients,
10%–20% of myasthenia gravis patients have thymoma

12. ASSOCIATED
MEDICAL
CONDITIONS
• Response to stress: Atrophy; return to normal size; ‘Rebound
Hyperplasia’
• Lymphoid Hyperplasia – Increase in lymphoid follicles; 65%
association with MG

13. IMAGING
• Radiological differentiation thymic hyperplasia vs neoplasm – Important
• Diffuse symmetric enlargement of the gland ≈ hyperplasia,
• focal mass ≈ Neoplasm (thymoma)
• However, differentiation may be difficult on the basis of morphologic features alone.
• Several new imaging approaches - Chemical shift MR imaging
• Normal thymus vs Thymic hyperplasia - Latter demonstrates homogeneously
decreased signal intensity on opposed-phase images
• May differentiate normal and hyperplastic thymus vs neoplastic involvement

14. THYMIC NEOPLASMS
• Thymic Epithelial Tumors:
• Thymoma
• Thymic Carcinoma
• Uncommon Thymic Neoplasms:
• Thymolipoma
• Thymic Carcinoid
• Lymphoma

15. CLASSIFICATION OF THYMIC
EPITHELIAL TUMORS
The WHO classification scheme correlates with invasiveness:
 Types A and AB are usually clinically benign and encapsulated (stage I)
 Type B has a greater likelihood of invasiveness (especially type B3)
 Type C is almost always invasive.

16. THYMIC NEOPLASMS
• Thymic Epithelial Tumors:
• Thymoma
• Thymic Carcinoma
• Uncommon Thymic Neoplasms:
• Thymolipoma
• Thymic Carcinoid
• Lymphoma

17. DIAGNOSTIC EVALUATION
• CT or MRI – most common modalities.
• Features assessed:
• Well-circumscribed or infiltration
• Signs of aggressiveness
• Infiltration into surrounding structure
• Atypical features – cystic areas, calcifications
• Important differentials:
• Retrosternal thyroid
• Lymphoma
• Germ cell tumor Several retrospective studies – Positive correlation of Invasive CT
features with more aggressive histotypes

19. Size Lobulated
Contour
Infiltration Pulmonary Nodules

20. MRI in THYMOMA
• T1-weighted images:
• Signal intensity similar to muscle or normal thymic
tissue
• T2-weighted images:
• heterogeneous

21. MRI in THYMOMA
• Useful in differentiating:
• Thymoma vs thymic cysts
• Latter demonstrates increased CT attenuation due to
hemorrhage or high mucinous content.
• T2-weighted & contrast-enhanced MR:
• detects solid components of cystic lesions
• a finding that raises the possibility of cystic thymoma

22. PET SCAN
• Value of PET scan to predict
• Histology
• Hyperplasia vs tumour
• Thymoma vs thymic carcinoma,
• Thymoma subtype, or
• Invasiveness
Debatable at best
(Kaira K et al. Ann Nucl Med 2011; 25: 247–253)
• PET – for subsequent follow-up of patients;
• to detect recurrences after first-line treatment
(El-Bawab HY et al. Interact Cardiovasc Thorac Surg 2010; 11: 395–399)

23. DIAGNOSTIC EVALUATION
• Histopathological diagnosis - through - small biopsy – PARAMOUNT
• Generally, Anterior mediastinal Tumors-
• Percutaneous core needle biopsy
• Mediastinotomy
• Mini-thoracotomy [30].
• FNA – Not recommended (cytological specimens of thymic tumours -
hard to interpret)
• Pleural spaces should not be punctured to avoid tumour cell seeding.
• D/ ∆s
• thymic hyperplasia,
• other primary mediastinal malignancies - lymphoma or germ-cell tumours.
• lung cancer
• How to handle small biopsy specimens

24. MASAOKA - KOGA
STAGING

25. MASAOKA - KOGA
STAGING

26. MASAOKA - KOGA
STAGING

28. PRESENTATION
CLINICAL EVALUATION
There are 2 main scenarios that the surgeon may find himself to deal with:
• Patient referred to the surgeon for a mediastinal lesion
• Patient referred to the surgeon for MG

29. SCENARIO – 1: Pt presents with a mediastinal mass on routine imaging
• In the first case, a thorough evaluation of the patient’s medical
history must be performed
• Assess Fluctuating muscle weakness
• Latent MG – protracted muscle weakness on NDMB (relaxants)
• Positive preop AChR level – risk of post-thymectomy MG – 1-3%;
warrants thorough neurological assessment
PRESENTATION

30. SCENARIO 2: Pt presents with a ∆s of MG
• Thorough clinical evaluation, serum Abs
• Chest imaging (CECT Chest) – to differentiate b/w thymic hyperplasia vs Early Thymoma
• Thymoma – definitive surgery; (Age < 60yrs)
• Thymic hyperplasia – Debatable options; based on the neurological disease
• Features on CT scan:
• Round/ oval shaped mass; moderately enhancing
• Size & extent of the disease
• Local invasiveness & distant spread (including pleural/ pericardial implants)
• Presence of foci of calcification or necrosis
PRESENTATION

32. SURGERY IN NON-THYMOMATOUS MG
Thymectomy Trial in Non- thymomatous Myasthenia Gravis Patients
Receiving Prednisone Therapy (MGTX)

33. PREOPERATIVE EVALUATION
• Combined Neurological & Anesthesiological assessment – myasthenic symptoms and
respiratory muscle strength.
• Coexisting disease should be investigated carefully, particularly those that could affect
MG, such as thyroid diseases.
• Details to pay attention:
• surgical approach
• prolonged operative time
• possible resection of the surrounding structures (in case of thymoma)

34. Factors predicting Postoperative Myasthenic Crisis (Leuzzi et al):
Lung function assessment (FEV1, FVC) - most important
parameters;
• in terms of pulmonary resection
• As a marker of disease control & postoperative crisis
PREOPERATIVE
EVALUATION

35. PRINCIPLES OF
SURGERY
• The primary therapy depends on staging
• Thorough preoperative staging required

36. STRATEGIES IN THYMIC EPITH TUMORS
• Primary strategy:
Upfront Surgery
Vs
Multimodality therapy
Complete resection represents the most significant and consistent prognostic
factor on disease-free and overall survival
• Unfortunately, no clinical staging system reliably predicts resectability

37. STRATEGIES IN THYMIC EPITH TUMORS

38. SURGICAL PRINCIPLES
• Median sternotomy - Wide opening of the mediastinum and both pleural cavities
• First step - Careful examination of the mediastinum and pleural cavities
• Evaluation of macroscopic capsular invasion, infiltration of peri-thymic and mediastinal
fat, peritumoral and pleural adherences, and involvement of surrounding tissues.
• Complete thymectomy - including the tumour, the residual thymus and perithymic fat,
invaded structures.
• Beware of Local recurrences (after partial thymectomy).
• Basis of staging – Intraop findings, subsequent pathological examination of the surgical
specimen.

39. SURGICAL PRINCIPLES
• Invasive tumour - en bloc removal of all affected structures; including - lung
parenchyma (usually through limited resection), great vessels, phrenic nerves and
pleural implants.
• Thoracotomy may be necessary.
• Areas of uncertain margins - marked with clips; allows precise delivery of post-
operative radiotherapy.
• Phrenic preservation vs resection (for R0) – should be balanced in patients with
severe myasthenia gravis.
• Frozen sections to assess tumour involvement of resection margins are not
recommended, given the high risk of false negative results.

40. SURGICAL ANATOMY
• Despite wide variability, the thymus is usually formed by 2
longitudinal spindles of capsulated tissue
• Fused in the middle - an asymmetric “H”
• 4 projecting extremities named “poles or horns”, similar to a
butterfly,
• Lengths and sizes of the poles are variable (commonly Inf Rt
horn-larger, Inf Lt – longer)
• Upper poles - thinner and reach the cervical area; lying deep to
sternothyroid muscle

41. SURGICAL ANATOMY
• In tight proximity to the recurrent laryngeal nerves
• Anatomic limits:
• Anteriorly – sternum
• Posteriorly - pericardium, left innominate vein, trachea
• Laterally - Mediastinal pleura up to the phrenic nerves
• Cranially - cervical region up to the thyroid.
• Many anatomic variants are described
• The most frequent - Innominate vein running anteriorly
along the left superior horn.

42. CONDUCT OF SURGERY - SURGICAL ANATOMY
Arterial supply:
• Tiny and inconstant
• Originate from the Internal mammary &
Inferior thyroid arteries.
Venous drainage:
• Much more evident
• Takes place through 1 or 3 wide collectors
• Drain into inferior aspect of Innominate vein.

43. ECTOPIC SITES

44. CONDUCT OF SURGERY
CLASSIFICATION
• Myasthenia Gravis Foundation of America (MGFA)
classification
• All resections are not equal in extent
• How much gross and microscopic thymus each
technique is capable of removing
• Comparison of outcomes b/w different techniques
• Surgeon-dependant – experience, technique,
patience, conviction & commitment
• Whether or not particular approach allows for total
thymectomy when properly performed.

45. TYPES OF SURGERY
Combined Transcervical and Transsternal Thymectomy (T-4)
Extended Cervico-mediastinal thymectomy
“Maximal” thymectomy
Jaretzki
• Benchmark operation against which other resectional procedures should
be measured
• These resections are basically exenteration.
• “Performed as if it were an en bloc dissection for a malignant tumor”
• Ensures no islands of thymus are left behind
• Guards against potential of seeding of thymus in the wound

46. TYPES OF SURGERY
Combined Transcervical and Transsternal Thymectomy (T-4)

47. CONDUCT OF SURGERY
• Separate Cervical and thoracic incisions.
• Wide exposure of neck and mediastinum is
obtained.
• A ‘T incision’ for
• large or malignant thymomas,
• reoperations,
• Obese with short neck pts.
• Mediastinal pleura incised bilaterally
retrosternally (arrows)
• From the level of the thoracic inlet to the
diaphragm

48. CONDUCT OF SURGERY
• Second mediastinal pleural incision (bilateral)
• Anterior to phrenic nerves.
• The posterior mediastinal pleura with adherent
phrenic nerve (arrow) are elevated
• Teased off bilaterally underlying fatty thymic
tissue.

49. CONDUCT OF SURGERY
• Sharp dissection on pericardium.
• En bloc resection from diaphragm to innominate vein
• From hilum to hilum,
• Including fatty thymic tissue in
• anterior pericardiophrenic fat
• "aortopulmonary window" (the left phrenic and vagus
nerves are especially at risk here)
• aortocaval groove
• lappets of pericardium extending into the thymus
• both sheets of mediastinal pleura
• The innominate vein identified & thymus separated from
it by dividing the thymic veins

50. CONDUCT OF SURGERY
• Cephalad to the innominate vein, the en bloc dissection is
continued
• posterior to the strap muscles
• medial to the recurrent nerves
• anterior to the trachea
• terminated at the level of the thyroid isthmus
• Fibrous cords traced to their cephalad termination or into
additional thymic lobes.
• Thyroid lobes mobilized; thymic tissue is searched for behind and
superior to the thyroid gland.
• On anatomical basis – any procedure less comprehensive - likely
to be incomplete.

51. TYPES OF SURGERY
Standard Transsternal Thymectomy (T-3a)
Standard transsternal thymectomy used by the pioneers
Blalock
(Followed by Keynes, Clagett)
• Originally limited to - Removal of the well-defined cervical-
mediastinal lobes
• Thought to be the entire gland
• Falls short of total thymectomy; residual thymus found in
neck & mediastinum at reoperation
• Considered Incomplete; no longer in use for Rx of MG
Alfred Blalock
Smoking did Kill him!

52. TYPES OF SURGERY
Extended Transsternal Thymectomy (T-3b)
Aggressive transsternal thymectomy
Transsternal Radical thymectomy
(Championed by Masaoka, Mulder etc)
• Similar to the Maximal-T4 technique; extent of resection varies
• Cervical thymic extensions are removed from below +/- some
additional cervical tissue
• NO formal neck dissection.
• Disadvantages - removes less tissue in the neck (30% ectopic)
• Mulder - risk RLN injury while extensive neck dissection of
maximal-T4 approach not “justified by the small potential gain”
Akira Masaoka (1930-2014)

53. TYPES OF SURGERY
Transcervical Thymectomies (T-1)
Basic Transcervical Thymectomy (T-1a)
Extended Transcervical Thymectomy (T-1b)
Extended Transcervical Thymectomy Variations (T-1c-d)

54. CONDUCT OF SURGERY
Transcervical route - can be considered the very first real minimally invasive approach.

55. TYPES OF SURGERY
Transcervical Thymectomies (T-1)
Basic Transcervical Thymectomy (T-1a):
• Employs intracapsular extraction of the mediastinal thymus
• Small cervical incision
• Limited to removal of intracapsular portion of the central cervical-mediastinal lobes.
• No other tissue is removed in neck or mediastinum
• Although considered “total”, unequivocally an incomplete resection
• In both the neck and the mediastinum
• Evidenced by findings of residual thymus during reoperations

56. TYPES OF SURGERY
Transcervical Thymectomies (T-1)
Extended Transcervical Thymectomy (T-1b): (Cooper technique)
• Employs special manubrial retractor - Improved exposure via cervical incision
• Mediastinal dissection is extracapsular; includes resection of visible mediastinal thymus
& fat
• Sharp dissection on pericardium +/- ; Inclusion of mediastinal pleural sheets +/- (less
often)
• Dissections vary in extent; exploration and removal may exceed limits of cervical-
mediastinal extensions
• Cooper – “when performed by others may be less extensive than the procedure
performed by us!”

57. TYPES OF SURGERY
Transcervical Thymectomies (T-1)
Extended Transcervical Thymectomy Variations (T-1c-d):
• Partial median sternotomy (T-1c)
• Use of Videoscopic technology (T-1d)
• Aids in visualization and dissection of the mediastinum.
• Video-assisted variations include addition of
• transcervical thoracoscopy or
• subxiphoid videoscopic inferior approach

58. TYPES OF SURGERY
Videoscopic-Assisted Thymectomies (T-2)
Classic VATS (Unilateral) (T-2a)
Video-Assisted Thoracoscopic Extended Thymectomy (Bilateral with
Cervical Incision) (T-2b)
Bilateral VATS (No Cervical Incision) (T-2c)

59. TYPES OF SURGERY
Videoscopic-Assisted Thymectomies (T-2)
Classic VATS (Unilateral) (T-2a):
• Complete removal of
• grossly identifiable thymus
• variable amounts of anterior mediastinal fat
• diaphragmatic fat, including,
• Cervical extensions
• Since unilateral - contralateral side of mediastinum is not well visualized

60. TYPES OF SURGERY
Videoscopic-Assisted Thymectomies (T-2)
Video-Assisted Thoracoscopic Extended Thymectomy (Bilateral with Cervical Incision)
(T-2b):
• The video-assisted thoracoscopic extended thymectomy (VATET)
• Bilateral thoracoscopic exposure - improved visualization of both sides
• A possible cervical incision - exposure of RLN & removal of cervical thymic lobes +
pretracheal fat under direct vision
• Extensive removal of the mediastinal thymus and perithymic fat is described
• Modifications to VATET include - addition of an anterior chest wall-lifting method
• Conceptually more complete than the unilateral VATS - Offers excellent visualization of
both sides & includes a neck dissection as well

61. TYPES OF SURGERY
Videoscopic-Assisted Thymectomies (T-2)
Bilateral VATS (No Cervical Incision) (T-2c):
• Similar resection capability to extended transsternal thymectomies (T-3b)
• Studies – 2-3% of thymic tissue may be left in the absence of additional
cervical approach
• Some authors prefer to refer it as VATET

62. CONDUCT OF SURGERY - VATS
• The thymus gland – approx. located in midline of anterosuperior mediastinum; lobulated,
including fat and glandular tissue.
• ‘Grey-ink’ colour (variable); within the diffuse yellow of mediastinal fat.
Initial view from the Left port. Initial view from the Right port.

63. CONDUCT OF SURGERY – VATS
Classic VATS (Unilateral) (T-2a)
• The thymus gland – approx. located in midline
of the anterosuperior mediastinum.
• Adults - appears as a lobulated structure,
including fat and glandular tissue.
• The ‘grey-ink’ colour (variable) identifies the
thymus in the diffuse yellow of mediastinal fat.
Initial view from the Left port.

64. CONDUCT OF SURGERY - VATS
Goal of a successful thymectomy for MG – “Remove as much thymic tissue as possible”
Must know all the sites of thymic distribution within the mediastinum
View from the Left port. View from the Right port.

65. Rückert JC et al , The Annals of Thoracic Surgery,
2000, Vol.70,Iss.5:1656-61
Thorascopic thymectomy (tThx)
> Transternal thymectomy
(sThx):
• Vital capacity
• Forced Vital capacity
• Forced Expratory Volume in 1st
sec
• Peak Expiratory Flow
TYPES OF SURGERY
Videoscopic with Robotic Technology (U/L
or B/L) (T-2d)

66. Evidence for MIT • Skepticism towards MIT w.r.t oncologocal results in early
years
• Debunked by several workers

67. TYPES OF SURGERY
Videoscopic with Robotic Technology (U/L or B/L) (T-2d)
• Introduction in the early 2000s
• Becoming increasingly common since then
• Advantages: The instrumentation offers
• Enhanced optics with three-dimensional visualization
• 12x magnification
• Surgical arms allows precise tissue dissection.
• Extensive, yet, safe resection of the thymus + anterior mediastinal fat + neck
exploration
• Disadvantages:
• significant cost and time to the procedure.

68. CONDUCT OF
SURGERY
A. Patient placed to the left
edge of the table with
the left arm placed
parallel to the table.
B. The prepped, sterilized
and draped operative
field.
C. Skin marks for three
trocars.
D. Port placements.

69. CONDUCT OF SURGERY
Resection starts in the middle of the pericardium and moves cranially along the nerve.

70. CONDUCT OF SURGERY
The incision proceeds to the right side until the right lung is visible,
but the right pleural cavity is still closed

71. CONDUCT OF SURGERY
Management of the upper poles and thymic veins.

72. CONDUCT OF SURGERY
The incision proceeds to the right side – at times right pleural cavity needs to be
opened.

73. TYPES OF SURGERY
Videoscopic with Robotic Technology (U/L or B/L) (T-2d)
Technical Tips:
• Patient positioning.
• To get enough space for movement of the instruments,
• Patient should be placed supine
• With the body moved to the left edge of the operating table
• Lowering the left arm to be parallel to the table
• Placing the right one naturally along the body
• Trocar placement.
• Some surgeons prefer the right-sided approach - Due to concerns of pericardial injury/
heart, while inserting the trocars through the left side
• Following 12-mm camera trocar, insufflation with CO2 to a pressure of 8 mmHg - Enlarges
the retrosternal space, facilitates insertion of the other trocars under vision.
• For the inexperienced, spatula used to push the heart aside, or lightly lifting the camera -
effective to acquire adequate space and ensure the safe placement of the trocars.

74. TYPES OF SURGERY
Videoscopic with Robotic Technology (U/L or B/L) (T-2d)
Technical Tips:
• Thymic upper pole resection.
• Bringing them down by constant retraction before resection - effective way to manage the
upper poles
• Thymic vein management.
• Usually, 2-3 thymic veins running about 2 cm before draining into the left innominate vein
• Therefore, special attention should be paid to identify the left innominate vein
• Avoid injury to thymic veins and the innominate vein
• The left innominate/superior vena cava angle is a common site for a thymic vein
• Also, common anatomic variations occur at the upper left horn and run behind the
innominate vein,
• Easy to handle through the left-sided approach.

75. TYPES OF SURGERY
Videoscopic with Robotic Technology (U/L or B/L) (T-2d)
Major Disadvantages:
• Increased procedural (docking) time
• High cost
• Emergencies - such as major bleeding, requiring open conversion,
• The undocking of the robotic system and sterilization of the operator
• Consume much valuable time
• Possibly resulting in the situation being more difficult to manage

76. TYPES OF SURGERY
Infrasternal Thymectomies (T-5)
• Subxiphoid incision, reportedly
• improved visualization and dissection of bilateral mediastinal spaces
• otherwise, difficult from a unilateral thoracoscopic approach
• Aesthetically more appealing results,
• Modifications:
• Bilateral thoracoscopic ports
• Cervical incision - to facilitate neck dissection;
• combined transcervical- subxiphoid thymectomy (T-5a)
• utilizes both an open cervical dissection and subxiphoid video- assisted inferior approach
• comparable resection to the “maximal” T-4 approach [64].
• Disadvantages:
• decreased manoeuvrability - increases operative time or hamper adequate dissection
• Robotic technology - overcomes these limitations in dexterity

77. TYPES OF SURGERY
Infrasternal
Thymectomies (T-5)
Subxiphoid Robotic-assisted
Thymectomy
(Takashi Suda)

78. LYMPH NODE METASTASES
• Incidence of LN Mets - largely undetermined in thymic epithelial tumours
• Literature unclear - how often nodes are biopsied or examined
• Landmark Japanese series (1320 resected thymic tumours) :
• lymph node invasion - mostly located in the anterior mediastinum and
• found in 2% of thymomas,
• 1% of stage I cases,
• 6% of stage III cases
• Nodal invasion higher in thymic carcinomas - anterior mediastinum (70%),
other intrathoracic locations (35%), and extrathoracic sites (30%)

79. lymph node metastases
• Unfavourable prognostic value – only for carcinomas
• Any suspicious nodes (enlarged, firm or hypermetabolic at PET- scan)
should be removed and separately labelled and submitted.
• Routine removal of anterior mediastinal nodes – for stage III–IV thymomas
• For thymic carcinoma - even more extensive nodal dissection (anterior
mediastinal, intrathoracic, supraclavicular and lower cervical areas)
LYMPH NODE METASTASES

80. ADJACENT STRUCTURE INVASION
II. Intraop detection of Phrenic N. involvement:
• Special concern in Myasthenoc pt
• PN-spearing Sx (when involved with tumor):
• No differenve in DFS or OS
• Recurrence rates were higher
• 5% of permanent postop diaphragmatic palsy
• 15% of resected PN – didn’t show tumor infiltration
III. Bilateral PN involvement:
• Mandatory to spare one of them – address with definitive RT
IV. Concomitant Pulmonary resections:
• Increased risk of BPF (in pts on steroids)

81. SURGICAL PRINCIPLES
Appropriate selection of patients for a MIT:
• location - in the anterior mediastinum
• tumor encapsulation
• distinct fat plane between tumor & vital organs
• existence of residual (normal) appearing thymic tissue
• no mass/compression effect
• unilateral tumor predominance
• tumor dimension - lesions <3 cm (tumors from 5-10 cm have also been resected)
• Most important of all - oncological & technical safety & completeness

82. SURGICAL PRINCIPLES
• The choice for MIT should not alter principles of complete resection:
• resection of the tumour.
• the thymus and the mediastinal fat.
• Dissection, visualisation & preservation - innominate vein, both phrenic nerves.
• sufficiently large access incision to prevent specimen disruption.
• use of a retrieval bag.
• exploration of the pleura.
• Conversion to open surgery is mandatory if required to achieve complete resection
• Should NOT be considered a complication/ failure of the minimal approach.

83. SURGICAL PATHOLOGY RECOMMENDATIONS
• Communication between surgeons and pathologists is crucial while sending the
specimen
• Responsibility of the operating surgeon
• Proper orientation of the specimen
• Designation of involved structures, organs or areas of concern
• Mediastinal board:
• consisting of a line diagram of the mediastinum
• placed on a simple cork or wax board.

84. SURGICAL PATHOLOGY RECOMMENDATIONS

85. SURGICAL PATHOLOGY RECOMMENDATIONS
• The operative note should mention the following elements:
• Characteristics of the tumor & invasiveness.
• Extent of resection performed.
• Presence and location of any adhesions that were simply divided (not suspicious for
involvement).
• Whether gross tumour was left behind and, if so, its location.
• Any additional structures or organs removed.
• Any sites of intra-operative concern.
• How these were marked on the specimen and in the patient.
• Which nodal areas were explored and the extent of assessment.
• The presence or absence of pleural and pericardial lesion.
SURGICAL PATHOLOGY RECOMMENDATIONS

86. MULTIMODALITY Rx PRINCIPLES

91. ADVANCED TUMORS

95. UNRESECTABLE TUMORS

99. SUMMARY

100. THANK YOU