Background: Pagetoid urothelial intraepithelial neoplasia (PUIN) is a form of secondary Extramammary Paget Disease (EMPD). It is a rare malignant condition seen on the female genitalia synchronous or metachronous with bladder cancer (BC).
Case presentation: A 66-year-old female presented with PUIN at the labia minora 2 years after an open anterior pelvic exenteration with ileal conduit urinary diversion for carcinoma in situ (CIS) of the bladder. PUIN of the vulva and vagina was confirmed by a punch biopsy and the patient underwent a radical vaginectomy with urethrectomy and inguinal sentinel node procedure. Immunohistochemically EMPD was identified by the expression tumor protein 63 (p63), cytokeratin 7, and cytokeratin 20 (CK20).
Conclusions: PUIN is a rare but distinct clinical entity as a form of secondary EMPD which can be differentiated from primary EMPD based on medical history, histology, and immunohistochemistry.
Keywords: Pagetoid urothelial intraepithelial neoplasia; bladder cancer; carcinoma in situ; extramammary Paget; urothelial cell carcinoma.