The occurrence of cutaneous metastases from malignant neoplasms occurs in from 1% to up to 9% of individuals, as determined at autopsy. Those metastases to the umbilicus are uncommon and represent only 10% of all secondary tumours which have spread to the skin 56. Epidemiological studies showed that this condition predominates in females 7.

From a review of the literature, umbilical neoplastic nodules can be due to a primary tumour in 38% of cases, due to endometriosis in 32% of individuals, and in 30% are actually secondary tumour deposits from a primary tumour elsewhere 8. If these nodules are secondary tumour deposits then the source of the primary tumour may be from the gastrointestinal (35–65%) and genitourinary (12–35%) tract. In addition, in 3–6% of cases it originates from haematological malignancies, or lung and breast cancers. In 15% to 30% of patients the source of the primary site of the tumour remains unknown 91011.

Sister Mary Joseph's nodules usually present as a painful lump on the anterior abdominal wall. It has irregular margins and a hard fibrous consistency. The surface may be ulcerated and necrotic, with either blood, serous, purulent, or mucous discharge from it. The size of the nodule usually ranges from 0.5 to 2 cm, although some nodules may reach up to 10 cm in size 8. High-resolution ultrasound (US) helps to clarify the clinical findings by detecting solid umbilical nodules, even if the diagnosis is difficult to make clinically. Moreover, careful examination and imaging of the abdominal contents may also point to the diagnosis 12.

A full understanding of the mechanisms whereby the tumour spreads to the umbilicus remains unclear. However, following anatomical criteria, and several hypothesis have been proposed.

The umbilical ring is a scar invaginated on the abdominal wall between the transversalis fascia and peritoneum. After birth, the foetal cord structures develop into ligaments or peritoneal folds: 1) median umbilical ligament secondary to the obliterating urachus, 2) medial umbilical ligaments (which are obliterated umbilical arteries); 3) ligamentum teres (obliterated left umbilical vein) that continues into 4) the falciform ligament. On the lateral umbilical folds the inferior epigastric vessels and, sometimes, a vestigial vitelline duct connecting the umbilicus to the ileum can be recognised. The umbilical region shows a rich arterial supply that includes the inferior epigastric and deep circumflex iliac branches of the external iliac artery, and the superior epigastric branch of the internal mammary artery.

The venous drainage includes several anastomotic branches, coming from cranially the axillary vein, through the internal mammary vein, and caudally, the femoral vein through the superficial epigastric vein. In addition, the umbilicus may be connected with the portal system, through small umbilical veins.

The lymphatic system connects the umbilical region to the axillary, inguinal, and para-aortic lymph nodes. The deep lymphatic system passes along the falciform ligament, pierces the diaphragm and enters the anterior mediastinum or courses to the nodes around the iliac arteries 12131415.

All these systems (arterial, venous and lymphatic) as described represent possible routes by which metastatic tumour cells could implant into the umbilical region.

It is reasonable to suggest that direct extension of tumour through the peritoneum is the preferred route for gastrointestinal tumours. Furthermore, the common association between hepatic and umbilical metastases might suggests that the hypothesis that the tumour spreads from the primary tumour to the liver through the portal system and then through the lymphatic and/or venous channels, they spread to the umbilicus. It is still unclear if the umbilical tumour spread precedes the hepatic spread or vice versa.

Renal cell carcinoma typically spreads via extra-renal extension, lymphatic dissemination or venous invasion by the tumour. Intraperitoneal spread may occur as a result of disruption of the renal capsule 16. The dissemination of neoplastic cell through the urachus is assumed to be the mechanism for the bladder cancers.

Haematogenous, lymphatic and venous spread all represent valid mechanisms of tumour spread from gynaecological cancers 714.

Usually the presence of an umbilical metastasis indicates a poor prognosis, is a sign of advanced neoplastic disease, and may not be amenable to surgery. The survival of these patients without treatment has been reported to range from 2 to 11 months from the time of initial diagnosis 171819.

However, recent studies have suggested that there are several factors which are able to influence the prognosis of such patients. Certain data has shown a better survival (mean 9.7 months) in patients who detect an umbilical metastasis before definitive treatment of the primary tumour. In contrast, when the lesion appears after the primary tumour has been treated then the survival for these patients does not exceed the 7.6 months 1617.

Moreover, the aetiology of the primary malignancy determines the prognosis. For example, a better survival rate for patients with primary ovarian carcinoma has been reported previously 14.

Finally, the type of treatment seems able to influence the patient's prognosis. Despite some authors proposing only palliative treatment because of these patients poor prognosis 101720, recent studies have demonstrated that there is a better survival (21 months) for patients if they are treated with a combination of surgery and adjuvant therapy instead of surgery alone (7.4 months) or chemotherapy alone (10.3 months) 9111418.

Obviously, the appropriateness of such an aggressive treatment approach is determined by the clinical state of the patient.