Unusual finding of endocervical-like mucinous epithelium in continuity with urothelium in endocervicosis of the urinary bladder

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2840395525426177 webcite.Endocervicosis in the urinary bladder is a rare benign condition, first recognised by Steele and Byrne in 1982 in their report of endocervical-like glands deep in the urinary bladder wall [1]. This lesion was identified as a distinct entity by Clement and Young in 1992 [2] and the glands subsequently noted to be similar to endocervical glands in their immunohistochemical expressions [3-5]. To the best of our knowledge, there are to date less than 40 cases reported in the world literature in the two decades since this entity was first described. Usually occurring in women of reproductive age and located in the posterior bladder wall, endocervicosis is generally thought to be an embryological disorder of the secondary mullerian system [6,7] and the mucinous analogue of mullerianosis; "mullerianosis" being a term first used by Young and Clement to encompass endocervicosis, endometriosis and endosalpingiosis in the bladder [6]. Implant following pelvic surgery has also been considered an aetiological possibility as some cases were associated with earlier pelvic surgery [4,8] while others [8-10] put forth metaplasia as another possible cause of this condition. Nonetheless, the aetiogenesis of this interesting lesion still remains an enigma and largely based on circumstantial evidence. We present a case where mucinous epithelium, morphologically similar to endocervical epithelium, was detected in continuity with urothelium in addition to the characteristic endocervicosis glands, a finding that has hitherto not been reported, although Young and Clement had noted tubal epithelium replacing urothelium in mullerianosis [6]. The surface mucinous epithelium, its adjacent urothelium and the endocervicosis glands were compared for their immunohistochemical expressions of cytokeratins (AE1/AE3, CK19, CK7, CK5/6, CK20), HBME-1, estrogen receptor (ER) and p