What causes a umbilical (belly button) mole to have hypopigmented (little pigment) dots and appear to be bleeding into the surrounding skin on one side?

From the Guidelines

A belly button mole with little pigment dots and bleeding into the skin on one side should be evaluated by a dermatologist promptly, as these features can be warning signs of potential skin cancer, particularly melanoma. These characteristics align with the "ABCD" warning signs: Asymmetry (uneven bleeding on one side), Border irregularity (bleeding into surrounding skin), Color variation (pigment dots), and Dynamics (evolving appearance) 1. The presence of these features warrants professional examination, as they can be indicative of melanoma, a type of skin cancer that can be life-threatening if not detected and treated early.

The belly button area can be difficult to self-monitor, and moles in this location can change due to friction from clothing or body movements. It is essential to schedule a dermatology appointment for proper evaluation, which may include dermoscopy (specialized skin examination) and possibly a biopsy if concerning features are present 1. Dermoscopy by an experienced physician enhances the diagnostic accuracy, and an automated video-dermoscopy system can provide improved diagnostic accuracy for patients with multiple atypical naevi in the follow-up.

Some key points to consider when evaluating a suspicious mole include:

• Asymmetry: uneven shape or uneven bleeding on one side
• Border irregularity: bleeding into surrounding skin or irregular edges
• Color variation: multiple colors or pigment dots
• Dynamics: evolving appearance or changes in size, shape, or color
• The "ugly duckling" concept: melanomas often do not fit the individual's naevus pattern

Diagnosis should be based on a full-thickness excisional biopsy with a minimal side margin, and processing by an experienced pathology institute is mandatory 1. The histology report should follow the American Joint Committee on Cancer (AJCC) classification and include information on the maximum thickness, mitotic rate, presence of ulceration, and clearance of the surgical margins. Early detection and treatment of problematic moles significantly improve outcomes, and mutation testing for treatable mutations is mandatory in patients with advanced disease 1.

From the Research

Belly Button Mole Characteristics

• The appearance of a belly button mole with little pigment dots and a bleeding-like effect into the skin on one side can be concerning, but the provided studies do not directly address this specific issue.
• The studies focus on cutaneous melanoma, its diagnosis, treatment, and management, rather than the characteristics of moles in general 2, 3, 4, 5, 6.

Cutaneous Melanoma Diagnosis and Treatment

• The diagnosis of cutaneous melanoma typically involves a biopsy, with excisional biopsy being the recommended method 2, 3, 4.
• Partial biopsies, such as shave and punch biopsies, can be used, but they may have higher upstaging rates compared to excisional biopsies 3, 6.
• The treatment of cutaneous melanoma usually involves surgical excision, with the width of the excision margin being a topic of debate 4, 5.

Excision Margins and Outcomes

• Studies have investigated the optimal excision margins for cutaneous melanoma, with some finding no significant difference in outcomes between narrow and wide margins 5.
• However, other studies suggest that narrow margins may be associated with a reduced need for complex surgical reconstruction 5.
• The impact of shave biopsy on diagnosis and management of cutaneous melanoma has also been studied, with findings suggesting that it can be a useful diagnostic tool, but may not always provide accurate staging information 6.