Sex and self-reported race: Factors associated with anal mucosal melanoma and anal mucosal pigmentation?

Background and objectives

Anal canal melanoma (ACM) is a rare, aggressive malignancy with an ominous prognosis. However, its associated factors are largely unknown. Therefore, we investigated potential independent associations of sex and self-reported race with ACM and physiological anal canal pigmentation.

Methods

Two case-control cohorts from a single institution in Miami, Florida, were evaluated. The biopsy cohort comprised 117 sequential patients evaluated prospectively for melanocytic cells/pigment and anal intraepithelial neoplasia (AIN)/squamous intraepithelial lesion (SIL) in anal transitional zone biopsies between January 2021 and August 2022. The melanoma cohort consisted of 28 patients diagnosed with ACM between January 2003 and August 2021 and 116 of the patients in the pigmentation cohort. Multivariable logistic regression analysis was conducted to examine independent factor associations.

Results

In the biopsy cohort, anal transitional melanocytic cells/pigment were identified in 48% (26/54) of Black patients compared to 17% (10/59) of White patients. Multivariable analysis demonstrated that White race was inversely associated with mucosal pigmentation (odds ratio (OR) = 0.19, 95% confidence interval (CI): 0.08–0.48, P < 0.001). Conversely, White race was associated with ACM (OR = 6.25, 95% CI: 2.07–18.81, P = 0.001). Male sex was also inversely associated with ACM (OR = 0.18, 95% CI: 0.07–0.47, P < 0.001). No significant correlations were observed between mucosal pigmentation and AIN/SIL or human immunodeficiency virus status.

Conclusions

There is an increased presence of anal transitional zone melanocytic cells in patients who self-reported as Black compared with those who self-reported as White, without sex predominance. Our multivariable regression across two case-control cohorts shows that female sex and White race (versus Black race) are independently associated with ACM, while White race (versus Black race) is inversely associated with pigment in anal canal biopsies. ACM shares several characteristics with ALM, which is overrepresented in Black individuals. Pigmentation was unrelated to squamous cell carcinoma precursor lesions.

Full text

https://www.xiahepublishing.com/2771-165X/JCTP-2025-00041

The study was recently published in the Journal of Clinical and Translational Pathology.

Journal of Clinical and Translational Pathology (JCTP) is the official scientific journal of the Chinese American Pathologists Association (CAPA). It publishes high quality peer-reviewed original research, reviews, perspectives, commentaries, and letters that are pertinent to clinical and translational pathology, including but not limited to anatomic pathology and clinical pathology. Basic scientific research on pathogenesis of diseases as well as application of pathology-related diagnostic techniques or methodologies also fit the scope of the JCTP.

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