Radiation Oncology/EMPD

Extramammary Paget's Disease

Overview

 * Intraepithelial neoplasm with glandular differentiation
 * Morphologically the same as Paget's disease of the breast, but unlike in the nipple, there is only rarely an underlying malignancy. It appears to be a primary epithelial malignancy
 * Areas of involvement: peno-scrotal area, perineum, perianal area, vulva, axillae, groin, umbilicus, eyelid
 * Tends to arise in sites where apocrine glands are present in high concentration
 * In cases with an underlying malignancy (~20% of cases), it is often a cutaneous adnexal carcinoma, usually of apocrine or eccrine glands
 * Presenting symptoms: pruritus, scaly eczematous lesion
 * Histology shows presence of Paget cells, which are large cells with abundant basophilic cytoplasm and a large hyperchromatic and pleomorphic nucleus. Staining positive for CEA, CK7, EMA, and CAM 5.2; may also show overexpression of Her2
 * Internal malignancies (e.g. colon, ovarian) may be associated in 10-20%
 * Primary treatment is surgery, but margin may be diffuse and difficult to clear. Suggested margins have been 3-5cm, Mohs should be considered
 * RT reasonable alternative if patient not a surgical candidate

Literature

 * Hong Kong; 2007 PMID 17665242 -- "Extramammary Paget's Disease in Chinese Males: A 21-year Experience." (Chiu TW, World J Surg. 2007 Oct;31(10):1941-6.)
 * Retrospective.
 * Outcome: recurrence rate 35% (simple WLE 60% vs. intraop frozen sections 25%)