IMAGES: Ectopic thymic cyst: A rare case report

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.

Hassall's corpuscles in the fine‐needle aspiration cytology of pediatric ectopic thymic tissue

“…On FNA, the typical findings in thymic tissue include small lymphocytes, with occasional scattered epithelioid cells, with only rare well‐defined Hassall's corpuscles described . In autopsy studies looking at fetuses, there has been a spectrum of morphology in the way Hassall's corpuscles appear, ranging from ill‐defined to oddly‐shaped .…”

“…On the cell block sections, rare spherical, concentric whorls of squamoid epithelioid cells were seen that stained negative for thymic T-lymphocyte markers, such as CD1a, and were compatible with On FNA, the typical findings in thymic tissue include small lymphocytes, with occasional scattered epithelioid cells, with only rare welldefined Hassall's corpuscles described. 6 In autopsy studies looking at fetuses, there has been a spectrum of morphology in the way Hassall's corpuscles appear, ranging from ill-defined to oddly-shaped. 7 Furthermore, over time, Hassall's corpuscles start to involute and the thymic tissue shows more adipose tissue with less lymphoid tissue.…”

Quiste tímico inusual de mediastino posterior en un paciente con neurofibromatosis

“…Incluso se han descrito con relativa mayor frecuencia a nivel cervical en relación con los primeros, tal como lo describe Bothale en su estudio. 8 En nuestro instituto es el primer caso en 15 años. Takeda 9 publicó en su serie que la prevalencia de quistes mediastinales es mayor en adultos que en niños.…”

A Rare Case of Multiloculated Cervical Thymic Cyst Masquerading as Tuberculous Adenitis

“…Being uncommon, they are rarely included in the clinical diagnosis of cervical masses and are commonly misdiagnosed as branchial cysts, lymphatic malformations, epidermoid cysts, dermoid cysts, thyroglossal cysts, lymphadenitis or neoplastic masses. [7].…”