Cystic Teratoma with Neuroectodermal Cyst and Choroid Plexus Like Epithelium, A Rare Entity in the Head and Neck: Case Report with Literature Review

<b>Background:</b> Cystic teratoma with neuroectodermal cyst and choroid plexus epithelium in the cheek has never been documented in the literature to date. We report the first example of a cystic teratoma with abundant neuroectodermal derivatives, like glial cells and papillary choroid plexus-like epithelium, within the masseteric space and with no intracranial involvement. <b>Patient presentation:</b> A two-year-old male child presented with a complaint of a slowly growing swelling on the left side of the face since birth with no history of fever, fatigue or weight loss or other similar swellings elsewhere. No relevant family history was noted. Subsequent investigations revealed a single large nontender well-marginated swelling of size 4.6 ×3.6 ×3.7 cm within the left masseteric space. Additionally, unilateral renal agenesis on the right side was identified on ultrasound scan. Surgical removal and subsequent histopathological examination revealed cystic cavities lined by flat cells, which at places showed choroid plexus-like papillary proliferations. The connective tissue capsule was predominantly of glial fibrillary material, lacking any presence of dermoid or epidermoid structures, bone, cartilage or any hard tissues. The immunohistochemical examination with glial fibrillary acidic protein, keratin, vimentin and S100 confirmed the neuroectodermal components. A final diagnosis of cystic teratoma with neuroectodermal cyst was made, arguing against dermoid or epidermoid teratomas. <b>Conclusion:</b> Cystic teratoma with neuroectodermal cyst features are common in the gonads, ovaries, or the midline, but is rare in the cheek region and never reported in the literature to date. The location is famous for dermoid/epidermoid cyst subtypes of cystic teratomas; however, a neuroectodermal cyst is an unusual presentation.