Physical examination revealed a dark-brown, ovoid shaped mass, tender, smooth, firm too hard, measures 4*2 cm in dimension, with well-defined margins. It is entirely extra-peritoneal. Other parts of abdominal and pelvic examination were insignificant. An abdominal USS with a 5MHz probe indicated an umbilical soft tissue mass with benign features with no visceral or nodal enlargements. A pelvic scan showed a grossly normal endometrial plate, absence of leiomyomata and normal adnexa. An excisional biopsy was done and the histopathological analysis revealed an extra-uterine endometrial tissue with no malignant changes (Figure 1).

DISCUSSION

Any organ or tissue may be involved in extra-pelvic endometriosis. Endometriotic tissue has been found in the Colon and Rectum causing cyclical per rectal bleed, in the bladder, the Lungs and the Brain, resulting in catamenial hematuria, hemoptysis and seizure [12]. Primary cutaneous endometriosis, otherwise called spontaneous, is the one that developed denovo. A secondary endometriosis is said to follow iatrogenic or traumatic scar [13] a result of direct, iatrogenic, lymphatic or hematogenous spread from pelvic endometriosis [14] or a result of metaplasia [15]. Primary umbilical endometriosis is a rarity as noted earlier [1]. There is no consensus on its pathogenesis, as various theories are put forward to explain this bizarre phenomenon [12]. The Umbilicus is considered to be a physiologic scar, therefore, has tropism for endometriosis like other scar tissues [14]. This may be the case in our patient, because, no preceding history of pelvic surgery was obtained. The differentials for an umbilical nodule are numerous, the cyclical pain, variation in color or size that coincides with menstruation is often the only hint for a clinical diagnosis [16]. The index patient also presented with the monthly cyclical pain and the color and size variation. A constant pain in an umbilical Endometrioma has also been reported [16]. In the absence of pain, during pregnancy and menopause, establishing a clinical diagnosis may be difficult. It is therefore pertinent to keep in view other differentials such as: pyogenic granuloma, umbilical polyp, melanocytic nevus, seborrheic keratosis, epithelial inclusion cyst, desmoid tumor, hemangioma and granular cell tumor [17]. An incarcerated umbilical hernia, omphalitis, keloid and foreign body granuloma may also present as umbilical nodule [16]. As noted earlier, malignant lesions of the umbilical skin such as melanoma, squamous and basal cell carcinoma, and metastatic Mary Joseph’s nodules from the gastrointestinal tract may also be found [5,17].

Although majority is diagnosed based on clinical suspicion, radiological assessment could improve the chance of making the right diagnosis. An ultrasound evidence of an umbilical hypoechoic mass with foci of hyperechoic regions and evidence of increased vascular flow on Doppler interrogation is very helpful [18]. An ultrasound scan can also help the surgeon to estimate the size of the nodule, involvement of the parietum, pelvic organs and other viscera like the colon [18]. In difficult cases an MRI may be done, especially if a pelvic endometriosis is suspected and to rule out transcoelomic spread of metastatic nodules from the gastrointestinal tract. The MRI features of an umbilical endometriosis reported are the presence of a homogeneous hypointense lesion on T1-weighted sequence with low signals on T2 weighting [19,20].

The rarity of umbilical endometriosis has made its treatment to be mainly dependent on the experience of the surgeon. Medical treatment has been tried in some patients, but no randomized controlled trial has been done to assess its efficacy [14,16]. The drugs commonly used include progesterone, nor-ethysterone, androgens like Danazol and Gonadotrophin Releasing Hormone analogue, such as Goserelin and Boserelin. The most consistent effect reported is the symptomatic relief of pain and reduction in the size of the nodule after medical treatment [17]. Surgery has so far remained the most promising treatment for umbilical endometriosis [21]. The goal should be a complete resection with no recurrence, but, this is an uphill task in a disease with tropism for scar tissue like endometriosis. Surgical umbilical resection with or without repair of underlying fascia and peritoneum, or enucleation of the endometrial nodule with preservation of the umbilicus are mostly done. Total resection of umbilicus is however, preferred, as it carries low risk of recurrence [17].

CONCLUSION

A spontaneous umbilical Endometrioma is rare, high index of suspicion is required regarding any umbilical nodule with cyclical symptoms, and the possibility of sinister differentials like metastatic adenocarcinomatous nodules should always be entertained.

CONFLICT OF INTEREST

None