5 x 6 cm nodule of the left posterior neck, waxing/waning in size, assess depth or if adherent to adjacent structures A subcutaneous T2 hyperintense cystic lesion is seen in the left posterior neck under a vitamin E capsule marker measuring 4.1 x 2.5 cm (image 33, series 901). This measures up to 3 cm in craniocaudal dimension (image 29, series 601). This has minimal mass effect on the underlying left trapezius muscle, however the fat plane between the cyst and muscle is preserved and there is no evidence of muscular invasion. Very thin peripheral enhancement is seen on the postcontrast images, however no internal enhancement is seen. Given its proximity to the skin surface, this may represent a sebaceous cyst. No other masses are identified.No cervical lymphadenopathy is seen. The airway appears patent. The visualized intracranial structures which include the posterior fossa are intact. The paranasal sinuses and mastoid air cells are clear.The parotid, submandibular, and thyroid glands appear intact. The carotid and vertebral vascular flow voids are intact.Degenerative changes are present on the seen in the lower cervical spine with scattered areas of neural foraminal narrowing, however no significant central canal stenosis.
Simple cyst involving the left posterior neck subcutaneous soft tissues. While this is nonspecific, given its proximity to the skin surface, this may represent a sebaceous cyst. No invasion of the underlying musculature.