Cervical Thymic Cyst: Rare Cystic Neck Swelling. Case report
Cervical thymic cysts are rarest cysts found in the neck. Nests of thymic tissue may be found anywhere along the descent of the thymic primordia from the angle of the mandible to the mediastinum. 50% of cervical thymic cysts extend into the mediastin
A 5-year-old boy presented to Niyati hospital, Ahmedabadwith complain of swelling over the right side of neck for1-year which had gradually increased in size over time with no associated pain,weight loss, or pressure symptoms. There was no significant family history. Hisgeneral physical examination appeared normal without any obvious deformities orabnormalities. Local examination revealed a 6x4 cm2 oval, nontender,and cystic swelling on the right side of neck at level II, III and IV. Historyof aspiration of fluid twice but no details available. All his other systemsseemed to be normal clinically.
MRI neck shows 8.5x4x2 cm well defined, smoothly outline,thin walled, cystic lesion is seen on right side of neck, extending from thelevel of angle of mandible up to supraclavicular region. (Figure 1) The cystwas posterior to the right sternocleidomastoid muscle and carotid sheathstructures. (Figure 2) Fine needleaspiration cytology was suggestive of infected developmental cyst. All otherhematological and biochemical investigations were within normal range.
The cyst was excised under general anesthesia with a 9-10 cmhorizontal incision two finger breadth below the body of the mandible. Surgicalexploration revealed that a single cystic swelling was found lying between theleft lobe of thyroid gland medially, internal jugular vein, and thesternocleidomastoid muscle anteriorly, extending form spinal process of secondvertebra to 1 cm above the clavicle. The mass was adherent to vagus nerve. Themass was completely excised in toto without any intraoperative complication. Postoperativeperiod was uneventful.
Histopathologically,the specimen consists of single large and multiple small grayish and brownishsoft tissues. Microscopic examination revealed multiple cystic spaces lined bycuboidal to squamous epithelium. The cyst contained numerous cholesterol cleftswith subepithelium showing fibrocartilagenous tissue, foreign body corpuscles,and Hassall’s corpuscles thereby diagnosed as a thymic cyst. The patient has beensymptom free for more than 12 months.