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| Year : 2015 | Volume
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| Issue : 1 | Page : 118-119 |
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| IMAGES: Ectopic thymic cyst: A rare case report |
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Kalpana A Bothale, Sadhana D Mahore, Pragati Karmarkar, Trupti Dongre
Department of Pathology, N.K.P. Salve Institute of Medical Sciences and Research Center, Nagpur, Maharashtra, India
Click here for correspondence address and email
| Date of Web Publication | 11-Feb-2015 |
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 Abstract | | |
Ectopic thymic tissue in the neck is rarely reported in medical literature. Being uncommon, they are rarely included in the clinical diagnosis of cervical cystic masses and are misdiagnosed by surgeons as branchial cysts, lymphatic malformations, epidermoid cysts, dermoid cysts or thyroglossal cysts, lymphadenitis or neoplastic masses. Although it is rare, cervical thymic cyst should be considered in the differential diagnosis of a lateral cystic neck mass. Here we report a rare case of thymic cyst in a young 15-year-old male child on the left side of the neck. Histopathology of the excised cyst revealed thymic tissue composed of prominent Hassall's corpuscles, cholesterol clefts, lymphoid aggregates and cyst lined by cuboidal and squamous cells. Keywords: Ectopic thymic tissue, Ectopic thymic cyst, Cervical thymic tissue
How to cite this article:
Bothale KA, Mahore SD, Karmarkar P, Dongre T. IMAGES: Ectopic thymic cyst: A rare case report. Indian J Pathol Microbiol 2015;58:118-9 |
| Introduction | |  |
Cervical thymic cysts are rare lesions often misdiagnosed clinically as branchial cyst. [1] Here we report a rare case of thymic cyst in a young 15-year-old male child on the left side of the neck. He presented with a soft, cystic fluctuating mass in the left side of neck. Surgical excision was done. Histopathology revealed an ectopic thymic cyst. Ectopic thymic tissue may be an infrequent finding, but it should be included in the differential diagnosis of neck masses, especially in children.
| Case Report | | |
A 15-year-old boy presented to outpatient department of surgery with history of slowly growing mass over left side of the neck of 2 months duration. It had gradually increased in size with no associated pain. His general examination was normal. Local examination revealed a 3 × 2 × 0.5 cm, oval, non-tender, soft mass on the left side of the neck. Clinical diagnosis was kept as a branchial cyst. Hematological and biochemical investigations were within normal limits. Fine-needle aspiration cytology was done. Aspirate was gelatinous fluid. Cytology revealed proteinaceous fluid. Possibility of a branchial cyst was kept. Excision of the cyst was done under general anesthesia. Transverse incision was taken over the swelling. The cyst was anterior to the sternocleidomastoid muscle. The cystic lesion separated from muscle and carotid sheath. Excision was done. The specimen was sent for histopathology.
Gross examination revealed cyst wall in bits with adjacent solid tissue, total measuring 3 × 2 × 0.5 cm. The cyst wall was thin with irregular brown areas and grayish white areas on luminal aspect.
Sections taken from different areas revealed a multiloculated cystic lesion composed of fibrocollagenous tissue, lymphoid aggregates, cholesterol granulomas and Hassall's corpuscles and lined with cuboidal and squamous cells. Lumen contained proteinaceous material [Figure 1] and [Figure 2]. Presence of Hassall's corpuscle confirmed the thymic tissue in the cyst wall [Figure 3]. Final histopathological diagnosis of the ectopic thymic cyst was given. | Figure 1: Photomicrograph showing the cyst wall containing lymphoid tissue and lumen showing proteinaceous fluid. (H and E stain, ×100)
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 | Figure 2: Photomicrograph showing the cyst wall lined by stratified squamous epithelium and containing lymphoid aggregates and cholesterol clefts (arrow). (H and E, ×400)
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 | Figure 3: Photomicrograph showing thymic tissue composed of Hassall's corpuscle (arrow) and lymphoid tissue in the cyst wall.
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| Discussion | | |
Ectopic thymic tissue in the neck is rarely reported in the medical literature. Ectopic thymic tissue may be an infrequent finding, but it should be included in the differential diagnosis of neck masses, especially in children. [2] Ectopic cervical thymic cysts in adults are rare. Being uncommon, ectopic thymic masses are rarely included in the clinical diagnosis of cervical cystic masses and are misdiagnosed by surgeons as branchial cysts, lymphatic malformations, epidermoid cysts, dermoid cysts or thyroglossal cysts, lymphadenitis or neoplastic masses. [3]
Cervical thymic cysts are rare embryonic remnants that develop along the course of thymic migration in the neck. They usually occur during infancy and childhood, and they are extremely rare in adults. [4],[5]
Differential diagnosis for cystic masses in the neck is done. Cystic masses of the neck are thyroglossal duct cysts, branchial cleft cysts, cystic hygromas, dermoid cysts, epidermoid cysts, thymic cysts, bronchogenic cysts (visceral cysts), and laryngoceles. Thymic cysts are very rare representing only 1% of cystic cervical masses. [6]
Cigliano et al. carried out retrospective study in nine patients with thymic cysts. They concluded that cases of thymic cysts are usually asymptomatic, appearing mainly as masses resembling a branchial cyst or lymphatic malformation. Laboratory and imaging investigations are not useful for preoperative diagnosis. In some cases the mass extends into the mediastinum. The histological findings of thymic tissue and Hassall's corpuscles in the cystic wall are diagnostic. Surgery is successful and uneventful. Surgical excision is accomplished by dissection of the cystic masses from the jugular vein, carotid artery and vagus nerve and from the sternocleidomastoid muscle. The presence of a normal thymus in the mediastinum must be documented preoperatively in order to avoid the risk of total thymectomy. If a cervical thymic cyst extends into the normal thymus, attempts should be made to preserve the thymus, especially in younger patients. Thymic cysts should always be included in the differential diagnosis of lateral cervical masses, especially in children. [5]
| References | | |
| 1. | Prabhakar G, Santhosh AN, Manjunath SS, Santosh KV. Cervical thymic cyst: A case report. Indian J Otolaryngol Head Neck Surg 2013;65 Suppl 1:S171-3.  |
| 2. | Terzakis G, Louverdis D, Vlachou S, Anastasopoulos G, Dokianakis G, Tsikou-Papafragou AJ. Ectopic thymic cyst in the neck. J Laryngol Otol 2000;114:318-20. |
| 3. | Prasad KK, Gupta RK, Jain M, Kar DK, Agarwal G. Cervical thymic cyst: Report of a case and review of the literature. Indian J Pathol Microbiol 2001;44:483-5. [ PUBMED]  |
| 4. | Na W, Jang SH, Min KW, Cho SH, Paik SS. Cervical thymic cyst presenting as a possible cystic nodal metastasis of papillary carcinoma in a 53-year-old man. Ear Nose Throat J 2011;90:437-8. |
| 5. | Cigliano B, Baltogiannis N, De Marco M, Faviou E, Antoniou D, De Luca U, et al. Cervical thymic cysts. Pediatr Surg Int 2007;23:1219-25. |
| 6. | Shenoy V, Kamath MP, Hegde MC, Rao Aroor R, Maller VV. Cervical thymic cyst: A rare differential diagnosis in lateral neck swelling. Case Rep Otolaryngol 2013;2013:350502. |
Correspondence Address:
Dr. Kalpana A Bothale
28, Shastri layout Khamla, Nagpur - 440 025. Maharashtra
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/0377-4929.151207
[Figure 1], [Figure 2], [Figure 3] |
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Hassallęs corpuscles in the fine-needle aspiration cytology of pediatric ectopic thymic tissue |
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| Sara E. Monaco,Fernando Escobar,Jeffrey P. Simons | | Diagnostic Cytopathology. 2017; 45(8): 735 | | [Pubmed] | [DOI] | | | 3 |
A Rare Case of Multiloculated Cervical Thymic Cyst Masquerading as Tuberculous Adenitis |
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