A Case of Mediastinal Mass

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A Case of Mediastinal Mass

  1. 1. PHYSICIANS’ MEET An interesting case of Thoracic mass Prof.S.SUNDAR’s unit, Dr.N. Arun Kumar, PG
  2. 2. Case scenario Indra 42/F, farmer, thiruvallur, c/o chest pain- 6 months c/o breathlessness- 1 month c/o hoarseness of voice- 1 month c/o double vision - 1 month
  3. 3. HOPI• c/o chest pain- 6 months - intermittent - left sided - pricking - not radiating - not ass.with sweating/palpitation - no aggravating/relieving factors • c/o breathlessness- 1 month - insidious - gradually progressing -not ass.with orthopnoea/PND • c/o double vision - 1 month - intermittent - appears as the day advances • h/o drooping of eyelids- past 1 month - occasionally; after severe exertion or prolonged exposure to sun light • h/o LOA &LOW- lost 3 kgs over 2 months
  4. 4. No h/o • Cough/hemoptysis • Syncope • Leg swelling • Abdomial distension • ↓ed urine output • Dysphagia • Headache/vomiting • Difficulty in appreciating colours • No other h/s/o cranial N abnormalities • No h/s/o weakness/sensory abnormalities/cerebellar involvement
  5. 5. Past history • Not a k/c of HTN/DM/BA/PT/CAD • No h/o sugeries/RT • No h/o chronic drug intake
  6. 6. Personal history • Married • 2 children • Normal regular menstrual cycles • Taking mixed diet • Non-smoker • Non-alcoholic
  7. 7. General examination • Conscious, dyspnoeic, oriented, afebrile • No pallor/cyanosis/clubbing/icterus/pedal edema/SLA • VITALS: • BP- 130/90 mmHg • PR- 90/min, regular, normal volume, no spl.characters • RR- 22/min • JVP- not raised • Temp- 99F
  8. 8. Systemic examination- RS • INSPECTION: • Trachea app.to be in midline • Apical impulse –not visible • Chest movements- bilaterally equal • No chest wall deformity • No scars/sinuses • No distended veins
  9. 9. • PALPATION: • Trachea- midline • Apical impulse- left 5th ICS at MCL • Chest movements –bilaterally equal • Chest measurements- WNL • No TF • VF- ↓ed in left infraclavicular & mammary regions • No Intercostal tenderness
  10. 10. • PERCUSSION: • Dullnote + in left infraclavicular & mammary regions • No percussion tenderness • Traube’s space- normal tympanitic note +
  11. 11. • AUSCULTATION: • Breath sounds ↓ed in left infraclavicular & mammary regions • VR ↓ed in the same regions • Rhonchi + in the same regions • No BBS
  12. 12. Other systems • CVS- S1,S2 +, no murmurs • P/A- soft, no organomegaly, no FF clinically
  13. 13. • CNS- • HMFs- normal; MMSE- 26/30 • Cranial nerves- clinically normal • Spinomotor system: Bulk- normal Tone- normal DTRs- brisk Power- 4/5 in shoulder, elbow, hip, knee 5/5 in wrist, ankle sup reflexes- normal plantar - ↓ ↓ • Sensory, cerebellar, autonomic- normal • Spinum & cranium- normal
  14. 14. PROVISIONAL DIAGNOSIS ? Myasthenia gravis ? Mediastinal mass ? Lung mass
  15. 15. Rx • Nasal O2 • Back rest • Antibiotics • Bronchodilators • Analgesics
  16. 16. Investigations CBC VALUES Hb 11.6 gm% TC 7,600 cells/cu.mm DC P60, L37, E3 ESR 4/10 PLATELETS 1.6 lakhs RBCs 4.1 million/cu.mm PCV 34 MCV 86.2 MCH 30.1 MCHC 34.2
  17. 17. • RBS- 160 mg% • Blood urea- 20mg% • Serum creatinine- 0.8mg% • Peripheral smear study- normal • ECG- NSR/WNL • Echo- normal study
  18. 18. CXR PA
  19. 19. CXR PA • A homogenous semi-rounded opacity of 8×3.5 cm, with well-defined border, in left midzone • Silhoutted with most of the left cardiac border • Trachea in midline • Mediastinal widening
  20. 20. Chest Physician’s opinion • CXR- left hilar mass lesion- • ? Mediastinal mass- Anteriorly located • Adv: • CECT Chest
  21. 21. Scanogram
  22. 22. CT Chest
  23. 23. CT Chest
  24. 24. CT chest
  25. 25. Chest CT • Thymic cyst • Suggested -HPE
  26. 26. Cardiothoracic surgeon’s opinion • Mediastinal mass • ? Thymoma • ? Thymic cyst • Plan : excision & Bx
  27. 27. • Huge cyst noted in left lobe of thymus • Left lobe excised • Sent for Bx
  28. 28. Histopathological diagnosis • Multilocular thymic cyst, with • Thymic hyperplasia
  29. 29. Anti AChR antibody
  30. 30. Repititive Nerve Stimulation test • Nerve tested: Facial nerve • Result: Decremental response noted in orbicularis oculi
  31. 31. Final diagnosis Multilocular Thymic Cyst with Thymic Hyperplasia Myasthenia Gravis
  32. 32. Rx added • Tab. Pyridostigmine 30 mg TID • Tab. Prednisolone 25 mg OD & stepping up the dose • Tab. Azathioprine 50 mg BD
  33. 33. Indra 42/f
  34. 34. Approach to mediastinal masses
  35. 35. Contents of mediastina Anterior mediastinum Middle mediastinum Posterior mediastinum Thymus Anterior group of mediastinal lymph nodes Internal mammary vessels Heart Ascending & transverse aortic arches Vena cavae Brachio-cephalic vessels Pulmonary vessels Phrenic nerve Trachea & main bronchus Descending aorta Esophagus Thoracic duct Azygous & hemi azygous veins Posterior group of mediastinal lymph nodes
  36. 36. TUMORS IN MEDIASTINA DIVISION OF MEDIASTINUM TUMORS Anterior mediastinum Thymoma, lymphoma, teratoma & thyroid masses Middle mediastinum Vascular masses, lymph node enlargements from metastases and granulomatous diseases & pleuropericardial and bronchogenic cysts Posterior mediastinum Neurogenic tumors, meningoceles, meningomyeloceles, gastro-enteric cysts & esophageal diverticula
  37. 37. THYMOMA Thymoma is a neoplasm of thymic epithelial cells & excludes other tumors affecting the thymus such as lymphoma & GCTs. Most common tumor of anterior superior mediastinum
  38. 38. Sex distribution in thymoma
  39. 39. Age • Most patients >40 years • Rare in children & adolescents; but aggressive
  40. 40. •Myasthenia gravis •Pure red cell aplasia • Neutrophil hypoplasia • Pancytopenia • Cushing’s syndrome • Carcinoid syndrome • DiGeorge syndrome • Lambert-Eaton Syndrome • Nephrotic syndrome •SIADH • Whipple’s disease • Lupus erythematosis • Pemphigus • Scleroderma • Polymyositis • Polyneuritis • Polyarthropathy • Addison’s disease • Hypogammaglobulinemia
  41. 41. Thymoma –Physician’s role commonly encountered paraneoplastic syndromes Myasthenia gravis Pure red cell aplasia Immunodeficiency Lamber-Eaton myasthenic syndrome
  42. 42. Mechanism of paraneoplastic syndromes in thymoma Epithelial cells & other stromal tissues of thymus influence the selection & maturation of T lymphocytes dysregulation of this system in thymoma Dysregulation of the lymphocytes’ positive & negative selection Abnormal proliferation, autoimmunity & immunodeficiency Paraneoplastic syndromes
  43. 43. Presentation in thymoma
  44. 44. Lab studies • CBC- anemia, thrombocytopenia, granulocytopenia (in pure red cell aplasia) • Peripheral smear study • Quantitative immunoglobulin assay to r/o immunodeficiency • Anti ACh receptor antibodies/repititive nerve stimulation tests/Edraphonium ameliorative tests to r/o myasthenia gravis • Bone marrow aspiration to r/o pure red cell aplasia
  45. 45. Imaging studies • CXR- mediastinal widening in PA views, retrosternal opacification in lateral view • CT Chest- to exclude or to characterize thymoma; to detect morphology of the mass, fat invasion, cysts, necrosis • Oncotropic tracers- thallium, Tc99m
  46. 46. Procedures • Imaging guided FNAC/Biopsy of the mass lesion
  47. 47. Pure red cell aplasia • Occurrence in thymoma -5% • Thrombocytopenia, granulocytopenia, autoantibody formation • 30% of patients resume normal hematopoiesis after thymectomy
  48. 48. Immunodeficiency • Hypo/agammaglobulinemia • Thymoma – in 10% of hypo- gammaglobulinemia cases • Combined humoral & cell-mediated immunodeficiency • May occurs several years after thymoma resection
  49. 49. Thymoma & Myasthenis Gravis
  50. 50. Myasthenia gravis • Neuromuscular disorder characterized by weakness & fatigability of skeletal muscles • Underlying defect- ↓ in the no. of ACh receptors at neuromuscular junction
  51. 51. Normal physiology at NMJ ACh synthesized & stored in presynaptic vesicles Released into synaptic cleft (in calcium dependent manner) Combines with binding sites on the AChR In the post synaptic membrane
  52. 52. Channel in the AChR opens Rapid entry of cation, chiefly Na+ Depolarization at the end-plate Initiation of APs that is propagated along the Muscle fiber Muscle contraction
  53. 53. Pathophysiology
  54. 54. Anti- muscle specific kinase (Anti-MuSK) antibodies Interfering with AChR clustering Myasthenia Gravis
  55. 55. Prevalence of MG • 1-7/10,000
  56. 56. Age • Women – 20s & 30s • Men – 50s & 60s
  57. 57. Sex distribution (F:M=3:2)
  58. 58. Clinical features • Cardinal features are weakness & fatigability of muscles • Cranial muscles- lid & extra ocular muscles- involved early • Diplopia & ptosis – common initial symptoms • Difficulty in chewing • Slurred sppech • Difficulty in swallowing with nasal regurgitation & aspiration • Proximal & asymmetric weakness • Preserved DTRs
  59. 59. Lab testing
  60. 60. Anti AChR & MuSK antibodies • Anti AChR Ab- Detected in 85% of generalized MG patients & 50% of ocular MG patients • Levels don’t correlate with severity • Anti MuSK Ab -40% of Anti AChR Ab negative patients with generalized MG patients • Anti MuSK Ab – rarely present in AChR Ab +ve patients & in ocular MG patients
  61. 61. Electrodiagnostic testing • Anti AChE medication –stopped 24 hour before • Electric shocks delivered at a rate of 2-3/sec to the appropriate nerves • APs recorded from the muscles • Decremental response- Rapid reduction of >10% in the amplitude of evoked responses
  62. 62. Edraphonium (Tensilon) test inj.atropine 0.6 mg iv (sos) to treat cholinergic crisis 2 mg iv Improvement in strength of muscle Test is positive (test terminated) 8 mg iv If no change in strength of muscle Test is terminated (independent of the result)
  63. 63. Differential Diagnoses of MG • Congenital myasthenic syndromes (CMS) • Drug induced myasthenia • Lambert-Eaton myasthenic syndrome (LEMS) • Neurasthenia • Hyperthyroidism • Botulism • Intracranial mass lesion • Progressive external ophthalmoplegia
  64. 64. Myasthenia gravis LEMS Postsynaptic disorder Presynaptic disorder Auto antibodies directed against AChR in post synaptic membrane Auto antibodies directed against P/Q calcium channels in presynaptic membrane Normal release of ACh from presynaptic nerve terminals Impaired release of ACh from presynaptic terminals Preserved DTRs Depressed or absent reflexes No autonomic changes Autonomic changes + Decremental response in repetitive nerve stimulation test Incremental response Most commonly associated with thymoma Most commonly associated with Small cell lung cancer
  65. 65. Treatment
  66. 66. Anti cholineEsterase • Pyridostigmine is most widely used drug • Starting dose: 30-60 mg TID/QID • Maximal dose: 120 mg QID • Over doasage may cause increased weakness or muscarinic effects • Atropine
  67. 67. Glucocorticoides • Starting dose: 15-25 mg/day • Stepwise increase in dose: 5mg/day by 2-3 days interval • Maximal dose: 60 mg/day • Improvement within few weeks • Maximal dose maintained for 3 months • Changed to alternate day regimen for next 3 months • Gradually tapered over months
  68. 68. Immunosuppressives • Azathioprine is most widely used drug • Dose range: 2-3 mg/kg • Given in divided doses • Synergistic therapeutic effect with glucocorticoides & may decrease the need of high dose of glucocorticoides • Beneficial effects in 3-6 months • Adverse effects:flu-like symptoms, BM depression & Liver function abnormalities
  69. 69. Plasmapheresis • 5 exchanges over a period of 2 weeks • 3-4 L/exchange • myasthenic crisis • improving patients condition prior to surgery (thymectomy) Indications
  70. 70. IVIGs • 2 gm/kg administered over 5 days • 400 mg/kg/day • myasthenic crisis • improving patients condition prior to surgery (thymectomy) Indications
  71. 71. Thymectomy • Surgical removal of thymoma- to prevent local tumor spread • Even in the absence of tumor, 85% of patients with MG, improves after thymectomy; • Of these, 35% achieve drug-free remission • MG patients with Anti-MuSK antibody, may not respond to thymectomy
  72. 72. Carry home messages… • Abnormal thymus in MG may be thymoma or thymic hyperplasia • Medical disorders associated with abnormal thymus may precede/with/succeed the onset of thymoma- follow up must after thymectomy; immunodeficiency may occur many years after thymus resection • Even MG patients with normal thymus, 85% of patients improve after thymectomy, of that 35% will achieve drug-free remission • Lone ocular myasthenia also associated with thymic abnormality • Anti MuSK Ab positive in 40% of Anti-AChR Ab negative MG patients.

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