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

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%)