[Cutaneous endometriosis--clinical case report]

CASE REPORT: A 26-year-old woman presented with a history of a dark red, asymptomatic, firm, dome-shaped tumor, approximately 2.5 cm in diameter. The nodule had been developing for one year near a scar in the lower abdominal wall. Her past medical history was significant for a caesarean section five years prior to presentation. Histopathological examination revealed numerous glands of various sizes exhibiting small to large lumina, surrounded by a cellular, edematous stroma composed of spindle-shaped cells or round large cells admixed with lymphocytes, plasma cells, and few eosinophils. COMMENT: Cutaneous endometriosis is a well recognized but uncommon entity, representing approximately 1 percent of all cases of ectopic endometrial tissue. It may arise spontaneously within the umbilicus or inguinal region, but the majority of lesions develop on surgical excisions of the abdominal and genital regions (cesarean sections, hysterectomy, laparotomy, laparoscopy, and episiotomy) in women of reproductive age. The pathogenesis of cutaneous endometriosis is still not clear and several theories have been put forward to explain its development. Despite its clinical rarity, cutaneous endometriosis is a well-known condition to dermatopathologists. Nevertheless, they should be aware of those unusual metaplastic changes that may represent a diagnostic pitfall.