endometriosis is a common gynaecological condition characterised by the presence of endometrial glands and stroma at extrauterine sites .
ectopic endometrial implants have been reported in nearly every tissue or organ , including the skin . of the reported cases of cutaneous endometriosis , over 70%
the case of primary cutaneous endometriosis described here remains a rare entity with a reported incidence of 0.51% of all extragenital endometrial ectopia .
in december 2012 , a 31-year - old caucasian woman presented to the dermatology outpatient clinic with a 1-month history of a persistent , raised lesion in the umbilicus .
the patient had noted swelling and one episode of spontaneous frank bleeding from the lesion .
there was no associated cyclical pain at the lesion site . at the time of examination ,
a single firm 0.5-cm black - coloured papule was seen within the umbilicus at the 3 o'clock position .
no discharge or underlying umbilical hernia was noted . the patient had a history of 2 previous melanomas : the first in 2003 on the left abdomen and the second on the right buttock in 2006 .
given the anatomical location , a skin punch biopsy of the umbilical lesion was performed . during dermatology review , 1 month later , it was noted that 3 distinct skin - coloured papules had appeared next to the initial lesion ( fig .
histological examination of the punch biopsy revealed a lesion in the superficial dermis comprising a single dilated glandular structure , surrounded by cellular endometrial - type stroma ( fig .
the gland was lined by a single layer of columnar cells , a few of which had apical cilia .
subsequent gynaecological evaluation revealed a 3-year history of dysmenorrhoea . a provisional diagnosis of coexistent pelvic endometriosis was made .
a diagnostic and therapeutic laparoscopic examination was advised if the patient remained unable to conceive over the following 6 months .
less than 30% of cutaneous endometriosis appears in the absence of a prior surgical history and is termed spontaneous ( primary ) cutaneous endometriosis . of these cases ,
umbilical endometriosis characteristically occurs in women of reproductive age , who present with an umbilical nodule at the site of a prior surgical incision associated with cyclical pain at the lesion site .
however , the inconsistent appearance and rarity of this phenomenon means it is often clinically misdiagnosed .
endometriomas under the skin have been described as red , blue , black or flesh - coloured .
classic associated symptoms include cyclical pain , discharge , bleeding or swelling of the lesion correlated with the menstrual cycle .
the most widely accepted pathogenesis of secondary endometriosis is the iatrogenic implantation of endometrial cells as a result of surgery , commonly laparoscopic procedures . however , the pathogenesis of primary endometriosis remains uncertain .
theories suggested include the implantation of cells through sanguineous or lymphatic spread , or differentiation from coelomic pluripotent cells in the skin .
the heterogeneity in the clinical presentation of cutaneous umbilical endometriosis reflects the breadth of differential diagnoses that may mimic the condition ( table 1 ) .
malignancies , in particular melanoma and umbilical metastasis of visceral carcinoma ( sister mary joseph nodule ) , must be considered .
distinctive dermatoscopic , ultrasonographic and magnetic resonance imaging findings   have been described ; however , histopathological examination remains the gold standard .
hormonal therapy in the form of gonadotropin - releasing hormone agonists , oral contraceptives and danazol may be given preoperatively to reduce the size of lesions and ameliorate symptoms consistent with pelvic endometriosis .
subsequent gynaecological evaluation for pelvic endometriosis is recommended for all patients . around 15% of patients
diagnosis of the umbilical skin lesion facilitated the provisional diagnosis and management of underlying symptomatic pelvic endometriosis .
of note , the patient in this case study has a strong history of melanoma .
recent data have reported a statistically significant association between endometriosis and the occurrence of melanoma .
further studies are required to examine the possible association of cutaneous endometriosis and the development of melanoma . in summary ,
nevertheless , it should be considered in the differential diagnosis when examining any umbilical lesion , even in absence of pathognomonic cyclical symptoms .
 cutaneous endometriosis that arises de novo , without a prior history of surgery , is a rare phenomenon . 
 the clinical diagnosis of cutaneous endometriosis remains challenging due to the variable clinical appearance and symptoms of the condition , and therefore must be considered in the differential diagnosis of any umbilical lesion . 
 we report a 31-year - old woman who presented with spontaneous cutaneous endometriosis of the umbilicus . 
Introduction
Case Report
Discussion
Disclosure Statement