三軍總醫院 外科部 一般外科1, 核子醫學部2,甲狀腺 腫瘤治療團隊3 鰓裂囊腫發現原發性微小甲狀腺乳突癌 Primary micropapillary thyroid carcinoma arising from branchial cleft cyst ：Case report and literature review 梁家銘1  諶鴻遠2 詹德全1 陳登偉1 俞志誠1 施銘朗1 Chia-Ming Liang 1, Hueng-Yuan Shen2,3, De-Chuan Chan 1, Teng-Wei Chen 1 Jyh-Cherng Yu 1, Ming-Lang Shih1,3 三軍總醫院 外科部 一般外科1, 核子醫學部2,甲狀腺 腫瘤治療團隊3 Division of General Surgery 1, Department of nuclear medicine2, Tumor Board of Thyroid Cancer3 Tri-Service General Hospital

Case presentation A 37-year-old woman, palpable mass in the left neck for 6 months PE: a 3 cm palpable mass in the L’t lateral neck ( level III) TSH:0.9 uIU/ml T3: 0.78ng/dl fT4:0.9 ng/dl CT scans:

Case presentation 2.7 cm cystic lesion FNA: suspected papillary thyroid carcinoma at other H , mets or primary ? No lesion in both thyroid 17.9X9.8 mm cystic lesion, L’t neck

Operation: Wide excision of branchial cleft cyst and lateral neck LN dissection Operative findings: A 3x1x1 cm cyst ( wall) with multiple enlarged LNs in level V, L’t neck Neck dissection in the level V, posterior triangle Frozen section showed PTC and only reactive nodes

Pathology 0.5X0.4 cm papillary carcinoma of branchial cleft cyst, Microscopically, one papillary microcarcinoma measuring 0.5 x 0.4 cm in dimension arising from branchial cleft cyst characterized by tumor cells with ground-glass nuclei and grooving infiltrating in the fibrotic stroma as well as psammoma bodies formation. No normal thyroid tissue present. The surgical margins are not assessable due to specimens not orientated. Please correlate with clinical presentation. Histologic examination demonstrated a single layer of cuboidal epithelium lining the cyst, as well as dense subepithelial lymphoid aggregates, cholesterol clefts, and cyst macrophages, all of which are typical of a branchial cys thyroid hormone replacement therapy, and she was well at 2 years of follow-up. 0.5X0.4 cm papillary carcinoma of branchial cleft cyst, LN level V (0/21) Immunohistochemical stains: TTF-1(+), Tg (+), HMCK (+) Post-OP Tg: 2.71 TSH: 0.08, free T4: 1.12 ATA (-) ( On T4)

Discussion The human thyroid gland derives mainly from one median anlage, which develops from invagination in the floor of the primitive pharynx at the base of the tongue. During its maturation, the anlage migrates downward along the transient thyroglossal duct, which undergoes atrophy prior to definitive thyroid formation. At the same time, lateral anlages of the two fourth branchial pouches participate in the development of the gland, from which two superior parathyroid glands and the lateral thyroid are derived. The ultimobranchial bodies originate in the fifth branchial pouches, and they migrate downward on each side of the neck. From these develop the parafollicular cells (C cells), which make calcitonin. The thyroglossal duct atrophies, and thus it is usually absent in a newborn. A faulty downward migration of the thyroid leads to ectopic thyroid tissue in the neck, and a failure of the duct to atrophy can give rise to thyroglossal duct cysts and cervical fistulae The development of branchial cysts is not completely understood. According to some older theories, branchial cysts are congenital abnormalities that occur as a result of an incomplete obliteration of pharyngeal pouches 2 to 4. From Seidel HM, et al: Mosby’s guide to physical examination, ed 7, St. Louis, 2011, Mosby.

Discussion Primary PTC in branchial cyst: extremely rare, (only 10 cases reported; 1% thyroglossal cysts carcinomas are PTC ) Neck node metastases are found in 20% BMJ Case Rep. 2012 Jul 9;2012. Ear Nose Throat J. 2006 Oct;85(10):675-6. Pubmed search paper, 針對primary PTC from BCC不多，相關有15篇大多是case report Sidhu’s criteria for the papillary carcinoma in branchial cleft cyst9 was suggested as (1) an epithelial lining layer, subepithelial lymphoid tissue collection, (2) normal thyroid tissue adjacent to the focus of papillary carcinoma within the wall (3) and no evidence of papillary carcinoma in the thyroid or other area.

No Age (yrs), Sex Si ze (cm) Tumor size (cm) FNA Pathology Si ze (cm) Tumor size (cm) FNA Treatment Author 1 20,M Primary Papillary carcinoma 6.0, L’t 1.0 Cystectomy+Total thyroidectomy and neck dissection Ruhl DS, et al, 2013 2 41, F Benign Cyst excision only Sagit M,et al, 2013 3 75, F Primary papillary microcarcinoma 15.0, R’t 0.5 PTC Xu JJ, et al, 2013 recurrent 4 35, F 3.1, L’t PTC  Cystectomy+Total thyroidectomy Karras S,et al, 2013 5 45,F 4.0, L’t Gollahalli PK, et al, 2013 LN(+) 6 34, F 3.4, R’t Cystectomy+R’t thyroidectomy and neck dissection Kushwaha JK, et al, 2012 7 3.0, R’t Cho JS,et al, 2011 8 49, M 4.5, R’t Park J, et al, 2010 9 46, F 2.0, L’t 1.8 Matsumoto K, et al, 1999 很多tumor大顆怕microcarcinoma missed不知

Take home message FNAC is usually not useful because predominant cystic lesion CT and sonography might be helpful for differential diagnosis: Primary or LN metastatic PTC Pathological exam is crucial