BRANCHIAL CLEFT CYST AS THE INITIAL IMPRESSION OF A METASTATIC THYROID PAPILLARY CARCINOMA: TWO CASE REPORTS

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1 RCHIL CLEFT CYST S THE IITIL IMPRESSIO OF METSTTIC THYROID PPILLRY CRCIOM: TWO CSE REPORTS Hung-Sheng Chi, 1 Ling-Feng Wang, 1 Feng-Yu Chiang, 1,2 Wen-Rei Kuo, 1,2 and Ka-Wo Lee 1,2 1 Department of Otolaryngology, Kaohsiung Medical University Hospital, and 2 Department of Otolaryngology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. ranchial cleft cysts are the most common lesions in lateral neck cysts, predominantly occurring in the fourth decade of life and without sexual propensity. Rare branchial cleft cysts are associated with malignant tumors metastatic from the oral cavity, nasal cavity, pharynx or thyroid gland. Occult thyroid papillary carcinomas often present as a solid mass in the lateral neck, with only a few cases revealing a branchial cleft cyst as the initial manifestation. Herein, we report two cases of metastatic thyroid papillary carcinoma that presented as lateral neck cysts, with preoperative diagnosis of branchial cleft cyst. Finally, after complete surgical resection and histopathologic examination, one case was diagnosed as cystic change of metastatic lymph node from thyroid papillary carcinoma, and the other was determined to be a branchial cleft cyst with concurrent lymph node metastasis from thyroid papillary carcinoma. When a branchial cleft cyst is diagnosed by clinical or histopathologic examination, a metastatic thyroid papillary carcinoma should be considered as part of the differential diagnosis. Key Words: branchial cleft cyst, thyroid papillary carcinoma (Kaohsiung J Med Sci 2007;23:634 8) First presented at the 81 st Conference of the Taiwan Otolaryngological Society, Taipei, Taiwan, Papillary carcinoma of the thyroid is the most common thyroid malignancy accounting for 80% of all thyroid cancers, and predominantly occurs in the third and fourth decades of life [1,2]. Papillary carcinomas have a propensity for lymphatic metastasis, and often, metastatic lymph nodes are palpable without the primary tumor being evident [3]. lthough rare, cystic metastasis in the neck lymph node can occur, and papillary thyroid carcinoma may present as a lateral neck cyst mimicking a branchial cyst [4]. In differentiating a solitary cystic nodal metastasis from a branchial cleft Received: February 16, 2007 ccepted: pril 18, 2007 ddress correspondence and reprint requests to: Dr Ka-Wo Lee, Department of Otolaryngology, Kaohsiung Medical University Hospital, 100 Tzyou 1 st Road, Kaohsiung 807, Taiwan. kawolee@kmu.edu.tw 634 cyst, radiographic evaluation by ultrasound or computed tomography (CT) may raise the suspicion of malignancy, but biopsy is the only way to confirm the diagnosis. Fine needle aspiration cytology (FC) is quick and easy to perform without any obvious complications, and thus should be arranged in such patients. lthough most lateral cervical cysts in young adult patients are found to be benign, lymphatic cystic metastasis of an occult thyroid papillary carcinoma should be considered, and, even if a true branchial cleft cyst has been diagnosed histopathologically, there may be concurrent metastatic thyroid papillary carcinoma. Our objective is to draw the reader s attention to the possibility of metastasis from an unsuspected thyroid carcinoma in young patients presenting with cystic neck mass mimicking branchial cleft cyst. Kaohsiung J Med Sci December 2007 Vol 23 o Elsevier. ll rights reserved.

2 ranchial cyst as first impression of thyroid papillary carcinoma Figure 1. () Computed tomography of Case 1 shows intracystic enhanced elements in the cyst (arrow). () eck ultrasound of Case 2 shows a mm cyst with thin and smooth outlines. Figure 2. () Case 1: cystic change of the metastatic lymph node. () Case 2: branchial cyst and two cystic metastatic lymph nodes from papillary thyroid carcinoma. CSE PRESETTIOS Case 1 38-year-old man presented with a 1-month history of a painless right-sided neck mass. Clinical examination revealed a cm smooth, round, non-tender, mobile mass at the anterior border of the middle third of the right sternocleidomastoid muscle. CT scans of the neck mass revealed a well-defined cystic lesion (Figure 1). He was admitted for further treatment under the impression of branchial cleft cyst. t resection, no tract was discovered connecting the cyst to the pharynx or hyoid bone and it was removed intact. Grossly, the excised specimen revealed a thin-walled cyst with chocolate-brown fluid content suggestive of previous hemorrhage (Figure 2). Pathologic examination showed the specimen to be a papillary carcinoma with a prominent cystic change in an enlarged lymph node (Figure 3). Postoperative thyroid ultrasound demonstrated nodules in both thyroid lobes. FC of the thyroid nodules showed colloid stain and was negative for malignancy. On retrospective examination of the CT scans, a nodular mass was noted at the posterior aspect of the right lobe, next to the esophagus, which can be difficult to access. Total thyroidectomy with bilateral selective nodal dissection was performed. Pathologic examination confirmed a unifocal papillary thyroid carcinoma, 1 1 cm in size, in the right thyroid lobe, without vascular and capsular invasion. ilateral lymph nodes showed metastatic papillary carcinomas. The patient was put on thyroid replacement therapy and remains well after 16 months. Case 2 24-year-old man presented with a 3-month history of a painless right-sided neck mass. Clinical examination Kaohsiung J Med Sci December 2007 Vol 23 o

3 H.S. Chi, L.F. Wang, F.Y. Chiang, et al Figure 3. () Case 1: a cystic lesion with complicated papillary projections within a lymph node is shown (original magnification, 20 ). Inset: lining cells with a typical ground-glass nucleus (original magnification, 400 ). () Case 2: another cystic lesion with underlying lymphoid stroma is shown (original magnification, 20 ). Inset: ciliated columnar cells of the cystic epithelium, indicating branchial cleft cyst (original magnification, 400 ). revealed a 4 6 cm non-tender, oval, movable mass with a smooth surface at the posterior border of the inferior third of the right sternocleidomastoid muscle. fter the experience of treating Case 1, thyroid ultrasound was arranged, which revealed the neck mass (Figure 1); a single nodule in the right thyroid lobe was also noted. Cytologic examination by fine needle aspiration of the cyst revealed chocolate-brown fluid grossly, and foamy macrophages without malignant cells. t extirpation of the cystic mass, no tract was found connecting the cyst to the pharynx or hyoid bone. In addition, two adjacent enlarged lymph nodes, both measuring 1 1 cm with cystic change, were also found and were excised at the same time (Figure 2). The gross appearance of the removed specimen showed a thin-walled cyst with chocolatebrown fluid, similar to that of Case 1. Histopathologic examination revealed a branchial cleft cyst lined with ciliated cuboidal epithelium with lymphoid stroma (Figure 3). The two lymph nodes were found to contain metastatic papillary carcinomas. eck CT identified a hypodense nodule in the right thyroid lobe, comparable with the findings of thyroid ultrasound. Total thyroidectomy was performed and no other pathologic lymph nodes were found. Pathologic examination confirmed a papillary carcinoma, 0.5 cm in largest diameter, in the left lobe, without extension beyond the thyroid gland, and a nodular goiter in the right lobe. The patient was put on thyroid replacement therapy and remains well 5 months later. 636 DISCUSSIO ranchial cysts most often appear in the second or third decades of life. In one review of 33 proven branchial cysts, it was noted that FC and CT or magnetic resonance imaging are useful for diagnosis [5]. In our two patients, the clinical pictures were those of typical branchial cysts without other palpable masses in the thyroid and neck during physical examination. efore extirpation of the cysts, CT of Case 1 showed a well-defined cystic mass; the final diagnosis was cystic change of a metastatic lymph node. FC was performed in Case 2 and revealed no malignant cells in the cyst; the pathologic diagnosis was branchial cleft cyst. Cervical metastasis in patients with occult thyroid carcinoma has been stated to occur in 30% of all cases of thyroid carcinoma [6], and these metastatic lymph nodes usually present as palpable solid masses in the anterior and lateral aspects of the neck. Rarely, as in Case 1, metastatic lymph node liquefaction of papillary thyroid carcinoma may present as a solitary neck cyst, and there have been little more than 35 such cases reported in the literature [4,7]. In patients with lateral neck cysts, an incidence of occult thyroid malignancy of approximately 11%, with a mean age of 29 years, was reported in one setting [7]. In patients initially presenting with lateral neck cysts, it might be difficult to make a clinical differentiation between a cystic lymph node metastatic from Kaohsiung J Med Sci December 2007 Vol 23 o 12

4 ranchial cyst as first impression of thyroid papillary carcinoma an impalpable occult thyroid papillary carcinoma and a benign cervical cyst. ecause treatment in such cases is very different from those for benign cervical cysts, it is of crucial importance that early detection of thyroid cancer in patients with a cervical cyst leads to improved mortality rate. In one analysis of patients with thyroid carcinoma, the mortality rate increased two- to three-fold with a 1 year delay in diagnosis [8]. In such a context, metastasis from papillary thyroid carcinoma should be considered in young patients who present with a branchial cyst. Ectopic thyroid papillary carcinoma may occur within a branchial cleft cyst, with several such cases having been reported [2,9 11]. The initial assessment of a patient who presents with a neck mass should include a thorough evaluation of the head and neck, a survey of the risk factors for malignancy, an FC analysis, and imaging with ultrasound or CT. ecause of the cystic structure of the lesion, FC may not be diagnostic, as in Case 2. The accuracy of FC in the diagnosis of cystic neck masses varies, with a false-negative rate ranging from 50% to 67% [12]. Ultrasound or CT may be used to evaluate such a cystic mass, providing important structural information. Low-density, well-defined unilocular masses with thin uniform enhancing rims are typically seen on CT scans of branchial cleft cysts. However, one previous report suggested that cystic metastasis of occult thyroid papillary carcinoma must be considered when enhanced elements on CT images are demonstrated within a cervical cystic lesion [13], like that for Case 1. Similarly, on ultrasound images, some authors report that an irregularly thick wall, internal debris and the presence of solid echogenic components adherent to the wall were specific for cystic metastasis of occult thyroid papillary carcinoma [14]. On the other hand, FC, ultrasound and CT cannot take the place of a tissue diagnosis, and an excisional biopsy should be performed for both diagnostic and therapeutic purposes. ccording to Sidhu et al [2], the cystic lesion in Case 2, which was lined with a ciliated cuboidal epithelium with lymphoid stroma, is a typical branchial cleft cyst. o evidence of intracystic malignancy was found, with the exclusion of ectopic thyroid papillary carcinoma. Thus, our second patient is a case of concurrent branchial cleft cyst and thyroid papillary carcinoma with metastatic lymph nodes. This is a very rare condition with only one previous case ever having been reported [13]. In summary, the presentation of a thyroid papillary carcinoma as a branchial cleft cyst has been reported in three situations: cystic lymph node metastasis of thyroid papillary carcinoma; ectopic thyroid papillary carcinoma within a branchial cleft cyst; and, most rarely, a true branchial cleft cyst with concurrent lymph node metastasis of thyroid papillary carcinoma. REFERECES 1. l-rahim, sa SL. Papillary thyroid carcinoma: an overview. rch Pathol Lab Med 2006;130: Sidhu S, Lioe TF, Clements. Thyroid papillary carcinoma in lateral neck cyst: missed primary tumour or ectopic thyroid carcinoma within a branchial cyst? J Laryngol Otol 2000;114: McDermott ID, Watters GW. Metastatic papillary thyroid carcinoma presenting as a typical branchial cyst. J Laryngol Otol 1996;110: Verge J, Guixa J, lejo M, et al. Cervical cystic lymph node metastasis as first manifestation of occult papillary thyroid carcinoma: report of seven cases. Head eck 1999; 21: Daoud FS. ranchial cyst: an often forgotten diagnosis. sian J Surg 2005;28: Hwang CF, Wu CM, Su CY, et al. long-standing cystic lymph node metastasis from occult thyroid carcinoma report of a case. J Laryngol Otol 1992;106: Seven H, Gurkan, Cinar U, et al. Incidence of occult thyroid carcinoma metastases in lateral cervical cysts. m J Otolaryngol 2004;25: Mazzaferri EL, Jhiang SM. Long-term impact of initial surgical and medical therapy on papillary and follicular thyroid cancer. m J Med 1994;97: Lanzafame S, Caltabiano R, Puzzo L, et al. Thyroid transcription factor 1 (TTF-1) and p63 expression in two primary thyroid papillary carcinomas of branchial cleft cysts. Virchows rch 2006;449: Fumarola, Trimboli P, Cavaliere R, et al. Thyroid papillary carcinoma arising in ectopic thyroid tissue within a neck branchial cyst. World J Surg Oncol 2006; 4: Matsumoto K, Watanabe Y, sano G. Thyroid papillary carcinoma arising in ectopic thyroid tissue within a branchial cleft cyst. Pathol Int 1999;49: Gourin CG, Johnson JT. Incidence of unsuspected metastases in lateral cervical cysts. Laryngoscope 2000; 110: akagawa T, Takashima T, Tomiyama K. Differential diagnosis of a lateral cervical cyst and solitary cystic lymph node metastasis of occult thyroid papillary carcinoma. J Laryngol Otol 2001;115: huja, g CF, King W, et al. Solitary cystic nodal metastasis from occult papillary carcinoma of the thyroid mimicking a branchial cyst: a potential pitfall. Clin Radiol 1998;53:61 3. Kaohsiung J Med Sci December 2007 Vol 23 o

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