SAT-152 - Primary Umbilical Endometriosis in a Nulliparous Woman

Endometriosis is the presence of functional endometrial tissue outside the uterine cavity, most commonly involving pelvic organs. It affects up to 10% of reproductive-age women worldwide. Umbilical endometriosis is a rare manifestation, accounting for 0.5–1.0% of all cases. Extra-pelvic endometriosis is often underrecognized, and symptoms characteristically worsen with menses. We report a rare case of primary umbilical endometriosis in a nulliparous woman, highlighting the importance of recognizing cyclical symptoms in atypical presentations.

Case Presentation

A 32-year-old nulliparous woman presented with cyclical umbilical pain associated with menstruation. The pain was severe, localized to the umbilicus, and exacerbated by touch. She reported progressive changes including hyperpigmentation, skin thickening, and increased moisture. Examination revealed a thickened, hyperpigmented, malodorous 1.5×2 cm lesion, markedly tender and non-mobile. She was started on topical clindamycin and referred to gynecology. Pelvic ultrasound identified incidental leiomyomas. CT imaging revealed a soft tissue density at the umbilicus and a urachal remnant, raising concern for a solid mass or infected urachal cyst. Eight months after initial presentation, she underwent excisional biopsy with umbilicoplasty. Intraoperative frozen section suggested endometrioma; final pathology confirmed endometriosis.

Discussion

Umbilical endometriosis, or Villar's nodule, presents as a discolored nodule with cyclical pain, swelling, and bleeding. It may be primary, occurring without prior surgery, or secondary, resulting from iatrogenic seeding. Diagnosis is frequently delayed due to a broad differential, including hernias, granulomas, cysts, and malignancy. The catamenial nature of symptoms may go unrecognized by non-gynecological providers. Imaging has limitations: ultrasound is relatively insensitive, and CT cannot reliably distinguish endometrioma from other lesions. MRI offers superior soft tissue characterization, but histopathology remains the gold standard. Surgical excision with clear margins is the primary treatment. Hormonal therapy may reduce recurrence. The incidental fibroids underscore the need for full gynecologic evaluation, with implications for fertility counselling.

Conclusion

Primary umbilical endometriosis is rare and frequently misdiagnosed. A tender umbilical nodule with cyclical, menstrual-related pain should raise early suspicion even without prior surgery. Wide local excision with pathologic confirmation is definitive. Ongoing gynecologic follow-up and fertility counselling remains essential.

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