An unusual combination of axillary extramammary Paget's disease and intradermal naevus.

Histochemical and immunohistochemical techniques were of exceptional importance for the accurate diagnosis of this case of axillary extramammary Paget’s disease combined with intradermal naevus. W. Broeckx, Edegemsestraat 106, B-2640 Mortsel (Belgium) Case Report A.B., born 1907, female, Caucasian. History An 84-year-old woman manifested for over a year a red, slowly expanding skin lesion in the left armpit. This lesion was discovered by chance and was asymptomatic. The patient was extraordinarily fit in view of her age. Clinical Findings The clinical examination showed a slightly elevated erythema-tous macula. The lesion was moderately infiltrated and measured 30×20 mm (fig. 1). There was no fixation with underlying structures in the armpit, and no deeper tumoral process could be observed. Further clinical examination revealed no other abnormalities. Histology A skin biopsy showed a tumoral cell population in the basal layers of the epidermis and a benign intradermal naevus in the underlying dermis (fig. 2). A mucin stain (PAS after amylase) showed the cell population only in the epidermis (fig. 3). The epithelial membrane antigen showed the same cell population (fig. 4). The cell population in the dermis was positively stained with protein S-100 but not the cell population in the epidermis (fig. 5). These findings excluded a melanoma in situ and confirmed the diagnosis of extramammary Paget’s disease in the armpit. The combination with an intradermal naevus seems to have been coincidental. Fig. 1. Slightly elevated and erythematous macula in the left armpit. Therapy A broad local excision of the lesion was conducted under sedation and local anaesthesia. The procedure and postoperative course were uneventful. Follow-Up After 2 years, the follow-up is still satisfactory. Laboratory Findings and Complementary Examinations A complete blood examination was normal. A dissemination examination consisting of a mammography, echography of the breasts, abdomen and pelvis, bone scintigraphy and thorax X-ray was also normal. It was concluded that it concerned a locally isolated focus of Paget’s disease in the armpit. Discussion Axillary extramammary Paget’s disease is a rare entity. It generally occurs in the genital regions [1]. In this case, it was a primary form of extramammary Paget’s disease since © 1995 S.KargerAG, Basel 1018-8665/95/1904-0341 $ 8.00/0