1. Carcinoma Showing Thymus-like Differentiation of Thyroid--- Case Report
呈現胸腺樣分化的甲狀腺癌--- 案例報告
蘇炳睿, 洪健齡, 黃士銘, 洪崇傑
國立成功大學附設醫院外科部一般外科
呈現胸腺樣分化的甲狀腺癌--- 案例報告
蘇炳睿, 洪健齡, 黃世銘, 洪崇傑
國立成功大學附設醫院外科部一般外科
Carcinoma showing thymus-like differentiation of thyroid--- Case report
Su-Ping Jui, Chien-Ling Hung, Shih-Ming Huang, Chung-Jye Hung
Division of General surgery, Department of surgery, National Cheng Kung University Hospital, Tainan, Taiwan

2. Case 1 68 y/o female HTN 10+ years with medical control
Right neck mass with mild tender for 3-4 months
BWL 4kg/3 months, frequent cough
Sono : Bilateral thyroid tumors with neck LNs
FNA : Favor papillary carcinoma

3. thyroid cancer involving isthmus and bilateral lobes, with metastatic lymphadenopathy at right neck, bilateral supraclavicular, pretracheal and superior mediastinum.

4. Total thyroidectomy + pretracheal LN dissection + Bil modified radical neck dissection + mediastinal LN dissection (through sternotomy)
單號:812115K06574
Pathologists: 張孔昭醫師 病解專醫字第258號
Lymph nodes: 29/45;
Distribution: Level VI (pretracheal, paratracheal
and prelaryngeal/Delphian)(4/4);
level Ⅱ-Ⅴ (bilateral neck): (25/41)

5. Right & left thyroid : Carcinoma with thymus-like elements (CASTLE)
PATHO:
Right & left thyroid : Carcinoma with thymus-like elements (CASTLE)
Regional, bilateral neck and mediastinal lymph node : metastatic (46/64)
CD5 (+)
Right & left thyroid : Carcinoma with thymus-like elements (CASTLE)
Left thyroid : Carcinoma with thymus-like elements (CASTLE), intrathyroid dissemination.
Regional lymph node : metastatic (4/4)
Bilateral neck lymph node : metastatic (right: 14/22; left: 11/19)
Medaistinal lymph node : metastatic (17/19)
CD117 (+)

6. 2015.07 patient refused chemotherapy and radiation therapy
Neck LN meta, Lung meta 2016/02/08 CT)
– Salvage RT (7000 cGy/35 fx/49 days)
Liver metastasis
Pleural seeding

7. Case 2 39 y/o female patient No underlying disease before
Left neck mass gradually becoming larger in 1 month
Sono: Left thyroid irregular hypoechoic mass, about 4.8*2.9cm
FNA: Papillary carcinoma
There is an irregular hypoechoic mass, about 4.8*2.9cm, in the posterolateral aspect of left lobe thyroid with encasement of the Lt common carotid artery
Left thyroid ca with trachea, esophagus and CCA displaement

8. 2011.04.06 Radical total thyroidectomy
Patho: Carcinoma with thymus-like elements
~ Adjuvant radiotherapy
Thyroid tumor bed: cGy/ 34 fractions/ 48 elapsed days
Neck and superior mediastinal lymphatics : 4500 cGy/ 25 fractions/ 35 elapsed days
Regular follow up without recurrence
Patho
Left thyroid : Carcinoma with thymus-like elements (CASTLE).
Right thyroid : Nodular hyperplasia without tumor involvement
Pretrcheal lymph node : Atrophic thymic tissue.

9. Discussion-- CASTLE Rare tumor first reported by Miyauchi in 1995
Fewer than 100 cases reported to date
Probably arising from ectopic thymus or branchial pouch remnants
FNA : limited diagnostic value
Low grade thyroid carcinoma with overall survival rate about 71% at 10 years
Nodal metastasis and tumor extension predict a worse prognosis

10. Staining patterns of several malignant thyroid tumors to be differentiated from CASTLE
(1) lobulation on cut surfaces; (2) an expansive growth pattern; (3) thick fibrous bands dividing the tumor; (4) the presence of many lymphocytes in the tumor; (5) perivascular spaces with lymphocytes; (6) infrequent mitoses; (7) lack of foci of an anaplastic, papillary, or follicular tumor; (8) oval, vesicular nuclei, sharply defined nucleoli and pale cytoplasm; (9) Hassall’s corpuscle-like structures; (10) absent or limited coagulative necrosis; and (11) immunoreactivity for CD5
CD 5 positive

11. No gold standard treatment Surgery
Thyroidectomy with/ without modified LN dissection
Complete resection --> long term survival
Irradiation
Should be considered for patients with positive or unknown nodal status?
Curative surgery with postoperative radiotherapy to improve local control?
Chemotherapy
No evidence of benefit, need further clinical investigation
Even when the tumor is not completely resected, certain levels of local control can be obtained by irradiation;