1. Considerations regarding the role of 99m Tc-tetrofosmin thymic scintigraphy in thymomas
Lidia Ionescu, Cipriana Stefanescu, Carmen Vulpoi,
Doina Butcovan, D. Ferariu, C. Radulescu, C. Diaconu
University of Medicine and Pharmacy, Iasi

2. CT –mainstay of thymic investigation
Thoracic CT scan has a reliable sensitivity and specificity in detecting thymic lesions
Elective method of diagnosis
One major difficulty is to differentiate for certain between thymic lymphoid hyperplasia and thymoma.
But in equivocal cases, other investigations can add suplimentary informations.

3. MV, male, 46 years old, 6w. history of MG- Oss
MV, male, 46 years old, 6w. history of MG- Oss. III, CT suspicious for thymoma, Op. 2004, histology- thymic lymphoid hyperplasia + mediastinal ectopies, post.op.- complete remission

4. GE, 19 years old man, Hashimoto thyroiditis, hemolytic anemia, (Hb-4g/dl), CT- thymoma, op.dec 2005, histology- thymic lymphoid hypertrophy

5. PF, female, 21 years old, MG- OSS III, CT- thymic hyperplasia, op
PF, female, 21 years old, MG- OSS III, CT- thymic hyperplasia, op Histology- lymphocitic thymoma

6. Imaging investigations
But in equivocal cases, thymic scintigraphy can add suplimentary informations to CT aspects.
Equivocal cases:
Association of thyro-thymic lesions
Tumor recurrence
Type of thymic lesions
Ectopic thymomas

7. Scintigraphy with 99mTc-tetrofosmin
Frequently used in the assessment of myocardial perfusion, conducted to incidental extracardiac uptake and detection of a mediastinal mass as it showed in few reported cases in the literature (Kotsalou I, Hawkins M)
This investigation is not yet included in the algorithm of diagnosis for mediastinal mass
But it must be considered a valuable alternative when conventional investigations fail to confirm a clinical suspicion, resulting in adequate decision making.

8. Thymic scintigraphy
Pathological uptake of 99mTc tetrofosmin appears in benign and malignant tumors through an incomplete understood mechanism.
But the increased number of mitochodrias and the degree of perfusion of the lesion seem to play an important role.

9. Thymic scintigraphy
Thymic scintigraphy can asses after the degree of up-take of the radiotracer on the early and late images
Normal thymus,
Hyperplasia and
Thymoma
Tumor recurrence
Ectopic thymomas

10. The 99m-Tc Tetrofosmin scintigraphy
Performed with standard doses, according to the worldwide accepted protocol.
An informed consent for the investigation is obtained from all the patients.
An AXIS Gamma camera (Philips), Siemens double-head detection and SPECT was used and acquired data were analyzed with an IBM specialized software.

11. 99m Tc Tetrofosmin
Lipophile molecule that crosses the cellular membranes according to electrochemical gradient and fluidity of the membrane.
It accumulates mainly in the mitochondria, which explains the fixation in cells with intense metabolism.

12. Equivocal cases
The association hyperthyroidy-myasthenia gravis is present mainly in autoimmune thyropathies such as Hashimoto’s thyroiditis or Grave’s disease
Usually myasthenia gravis is secondary to hyperthyroidy due to thymus hyperplasia and an adequate antithyroid drug treatment or surgery result in remission of thymic hyperplasia.

13. Associated lesions
Murakami, Yasuhiro Hosoi demonstrated the presence of thymic hyperplasia in Grave’s disease patients, calculating on CT scan images the size and density of the thymus on untreated and treated Grave’s disease patients.
The conclusion was that thymic hyperplasia regresses in treated patients either with antithyroid drugs or total thyroidectomy

14. Thyro-thymic lesions
Yamanaka K, Nakayama H. reported a case of Grave's disease associated with a mediastinl mass in whom CT scan RMI were suggestive for a thymoma.
The patient underwent total thyroidectomy and thymectomy at the same stage. Pathology report showed a thymic hyperplasia.

15. AM, 46-year-old woman, 2007 multinodular goitre and myasthenia gravis Thyroid profile (TSH-0.1 µUI/ml, fT4-1.2ng/dl), Thyroid total volume of 65.9 ml. (Prof. dr. C. Vulpoi)
Compressive goiter
Retrosternal goiter

16. Total thyroidectomy for MNG-2007, Myasthenia gravis aggravated
Normal Chest
Normal thymus

17. Thymic scintigraphy Hypercaptation of 99mTc-tf
Thymic scintigraphy Hypercaptation of 99mTc-tf. consistent with a thymoma

18. Hyperthyroidism+ectopic thymoma
The thyroid lesion more obvious, was first treated and myasthenia gravis considered wrongly to be secondary and remitting after total thyroidectomy.
On thymic scintigrapy was evident the hypercaptation in lower anterior mediastinum with a high suspicion of a thymoma.
Pathology report of the specimen was mixt thymoma with capsular microscopic invasion-Masaoka II stage.

19. Repeat CT scan Antero- inferior mediastinal mass Thymectomy, 6 months following TT, june 2008
Paramedian low retrosternal mass
Well-encapsulated mass

20. Hyperthyroidism+ectopic thymoma
The thyroid lesion more obvious, was first treated and myasthenia gravis considered wrongly to be secondary and remitting after total thyroidectomy.
On thymic scintigrapy was evident the hypercaptation in lower anterior mediastinum with a high suspicion of a thymoma.
Pathology report of the specimen was mixt thymoma with capsular microscopic invasion-Masaoka II stage.

21. Myasthenia gravis, invasive thymoma Inflammatory pericarditis
C T, 64-year-old woman
8 year-history of MG, CT- evident tumour
op thymectomy+pleurectomy
Pathology report- Invasive thymoma-Masaoka III
Post-operative radiotherapy 44 Gy,
Chemotherapy 1 year- CPh+PDN
post-radiotherapy transient myxedema

22. CT, 60 years old, thymoma+MG, Oss. IV, op
CT, 60 years old, thymoma+MG, Oss.IV, op. 2002, Lymphocitic thymoma (type I malignant thymoma)-Masaoka II ( well encapsulated but microscopic capsular invasion), adhesions to left M. pleura which was resected

23. Radiotherapy 44 Gy, chemotherapy, 1 year CP+PDN Pericarditis at 1 year postRxT Remission of MG 5 years, AChE

26. POSTOPERATIVE THYMIC SCINTIGRAPHY LACK OF RADIOTRACER FIXATION IN THE ANTERIOR MEDIASTINUM

27. CT aspects-2009 The absence of the tumour recurrence, pericarditis

28. 2009 Inflammatory pericarditis