56 Epidermoid cyst mimicking appendiceal mucocoele

Abstract

Abstract Background Congenital epidermoid cysts found in internal organs are thought to arise from displaced or implanted ectoderm during embryonic development. Their histogenesis differs from that of acquired cysts which are associated with trauma or iatrogenic implantation. Epidermoid cysts related to caecum or appendix are rare. The present case describes the largest caecal epidermoid cyst reported in the English literature so far in a patient with no previous history of surgery or trauma. Case report A man in his late thirties presented with a three-week history of dull right-sided abdominal pain. Physical examination revealed right flank fullness and subsequent CT scan showed a large right-sided cystic mass adjacent to caecum. The appendix could not be visualised separately and the mass was thought to be either an appendiceal mucocoele or an inclusion cyst. Cryptorchidism was excluded. Due to concerns of possible mucocoele that could lead to pseudomyxoma peritonei, laparotomy was performed and the cyst was excised intact with an ileocaecectomy. The specimen weighed 1.8kg and was 120 x 105 x 95mm in size. Histological findings were consistent with an epidermoid cyst inseparable from caecum and appendix, visibly distinct from the appendiceal wall stretching over it. Conclusion Epidermoid cysts related to caecum or appendix are rare benign lesions. In the present case, the cyst was safely excised via an open ileocaecetomy, based on its location and concern for an appendiceal mucocoele. Ileocaecectomy or segmental colectomy with primary anastomosis can be safe surgical management options for caecal cysts in an otherwise healthy patient.