Intra-Infundibular Epidermoid Cysts: A Distinct and Rare Entity

Epidermoid cysts located completely within the pituitary infundibulum are a rare entity with only 7 reported cases. In this study, we have described our experience with the resection of intra-infundibular epidermoid cysts (IECs) and reviewed the existing literature highlighting its distinguishing features and operative nuances.

Three consecutive cases of IEC operated at our institute were retrospectively studied. PubMed and EMBASE databases were searched, and 7 case reports of IEC were found. Relevant clinical, radiological, and operative data of 10 cases were analyzed.

The median age at diagnosis was 53.5 years, and 6 cases were males. Preoperatively, although the average tumor size was only 1.62 cm³, 80% of patients had visual disturbance, and 78% of patients had a deficiency in pituitary hormones. Five patients had preoperative diabetes insipidus. Mild diffusion restriction was noted in 4 out of 5 cases that mentioned it. The most common differential diagnosis considered was Rathke's cleft cyst and craniopharyngioma. Adhesion of the cyst wall to the stalk and/or the hypothalamus was a common occurrence resulting in residual wall being left behind in 50% of cases. An expanded endoscopic endonasal approach was utilized in 9 cases, and 1 case underwent frontotemporal craniotomy with resection via pretemporal approach. Postoperative chemical meningitis was demonstrated in 2 cases, and a sterile abscess was noted in another case.

IECs are rare tumors that are often misdiagnosed preoperatively. They have different postoperative morbidity profiles compared to other cystic lesions in the infundibulum. This makes it important to recognize this distinct entity.