Brown Umbilical Nodule: A Case of Primary Cutaneous Endometriosis

Abstract

Background

Endometriosis is a common condition in which endometrial glands and stroma are implanted outside the uterine cavity. Rarely, the skin can be involved.

Case Presentation

We describe a case of a 41-year-old woman who presented to the dermatology clinic complaining of a brown umbilical nodule with slight erythema. It was occasionally painful and hemorrhagic. She denied a history of endometriosis and abdominal surgeries. A shave biopsy of the nodule was consistent with a diagnosis of cutaneous endometriosis. The patient was referred to her gynecologist for further evaluation and treatment.

Conclusion

This unique case demonstrates primary cutaneous endometriosis in the umbilicus of a female patient. Cutaneous endometriosis can be classified as primary or secondary. Primary cutaneous endometriosis is rarer and has an unclear etiology, developing seemingly spontaneously without history of surgical interventions. Secondary cutaneous endometriosis typically arises within surgical scars following abdominal operations, which is believed to be a result of iatrogenic implantation of endometrial cells. Definitive treatment involves surgery. This case highlights the importance of considering cutaneous endometriosis in the differential diagnosis of a female patient with painful and intermittently hemorrhagic skin nodules.

Introduction

Endometriosis is a condition in which ectopic endometrial glands and/or stroma are found outside the endometrium, most commonly in the surrounding pelvic organs. In less than 1% of cases, endometriosis can affect the skin, which is called cutaneous endometriosis.¹ This form of the disease can be classified as primary or secondary based on a patient’s history for inciting factors. Secondary endometriosis usually arises within surgical scars following abdominal operations, widely believed to be the result of iatrogenic implantation of endometrial cells stimulated by laparoscopic procedures or cesarean sections.¹ Primary endometriosis is rarer and has an unclear pathogenesis, believed to spontaneously arise in these affected individuals without any inciting abdominal or gynecological procedures, as with secondary endometriosis.¹

Case Presentation

A 41-year-old Asian woman with a past medical history of atopic dermatitis, verruca vulgaris, allergic rhinitis, alpha thalassemia, and retinal detachment presented to the dermatology clinic with a brown and slightly erythematous nodule near her umbilicus that was noted during examination. The lesion had been present for 1 or 2 years with occasional bleeding and localized pain (Figure 1).

Figure 1.

A brown umbilical nodule was noted on examination.

She believed the cause of hemorrhage was due to the lesion rubbing on clothing. She had tried treating the lesion with hydrogen peroxide and a topical antibiotic ointment at home. The pain was localized to the umbilicus and did not radiate.

A shave biopsy was performed. Histopathologic examination revealed an area of fibrous stroma with glandular structures lined by a ciliated columnar epithelium. Erythrocytes and hemosiderin deposition were present in the surrounding stroma (Figures 2 and 3). These histopathologic findings were consistent with primary cutaneous endometriosis given her medical history.

Figure 2.

Islands of dilated endometrial glands in dermis surrounded by fibrovascular myxoid stroma and extravasated red blood cells, (H&E, 4x).

Figure 3.

Columnar epithelium lining the endometrial glands with extravasated red blood cells, hemosiderin and surrounding fibrovascular myxoid stroma, (H&E, 40x).

An additional gynecologic review of systems revealed menarche at age 13 and regular menses usually lasting 5 to 7 days with menorrhagia. She delivered 2 children vaginally at the ages of 24 and 26, and she reported 1 termination of pregnancy. The patient used oral contraceptive pills intermittently from ages 15 to 39, and she experienced amenorrhea from ages 33 to 39 while on this medication. Since the lesion onset, the patient was sexually active with 1 male partner. She denied a history of endometriosis and abdominal surgeries. She was referred to her gynecologist for further evaluation and treatment.

Discussion

The umbilicus is the most common cutaneous site for ectopic endometrial tissue, involving 30%–40% of all cutaneous endometriosis cases.² For either primary or secondary forms, it presents as an approximately 2 cm, firm, subcutaneous, variably-colored nodule in women of reproductive age.³ Symptoms associated with the more common forms of endometriosis, such as cyclical pain, swelling, and bleeding that corresponds with the menstrual cycle, are also seen in patients with the cutaneous variant.⁴ Primary cutaneous endometriosis, as diagnosed in our patient, may have a pathogenesis related to the theories of lymphatic or vascular migration or seeding whereby the endometrial tissue is implanted at a cutaneous site, such as the umbilicus.^1,5

Skin biopsy or excision is the most definitive diagnostic option. However, other modalities, such as ultrasonography, computed tomography, and magnetic resonance imaging, can be considered to exclude other possible diagnoses prior to surgical intervention.³ Histology demonstrates islands of endometrial glands with columnar epithelium and stroma in the skin, both containing morphologically similar clear cells.⁶ The correlation to endometrial glands includes high levels of mitotic activity, signifying glandular proliferation, as well as evidence of cyclical variations of the epithelial and stromal components of the cutaneous endometrioma.⁶ A meta-analysis of endometriosis-associated malignant transformation in abdominal surgical scars found that 67% (32/48) of patients were diagnosed with clear-cell carcinoma.⁷ This meta-analysis also asserts that “routine imaging is not helpful in detecting malignancy, and there is no specific marker for the malignant transformation.”⁷

A review of the literature reveals no standardized specialty referral for surgery. According to Matei et al, medical management, which can attempt to decrease the size of the lesion prior to excision, consists of systemic therapy, including “gonadotropin releasing hormone agonists, danazol, [and] preoperative or postoperative progesterone.”³ Wide local excision with 1 cm margins in order to prevent recurrence is the first-line recommended treatment.^3,8 Those who are diagnosed with cutaneous endometriosis should be referred to a gynecologist for further evaluation and management if they also have noncutaneous symptoms of endometriosis, such as dysmenorrhea, dyspareunia, or infertility.²

Conclusion

Although it is a rare entity, cutaneous endometriosis should remain in the differential diagnosis for women who present with painful and hemorrhagic skin nodules.