Background

Malignant melanoma is an aggressive malignancy in which prognosis is strongly determined by tumour thickness, ulceration, and other histopathologic prognostic indicators. In African populations, melanoma commonly presents at acral sites and is frequently diagnosed at advanced stages. Contemporary Nigerian data incorporating standardized microstaging variables remain limited. This study evaluated the clinicopathologic characteristics and prognostic histopathologic features of malignant melanoma diagnosed at a tertiary hospital in Southeast Nigeria.

Methods

A retrospective clinicopathologic review was conducted in the Department of Histopathology, Nnamdi Azikiwe University Teaching Hospital (NAUTH), Nnewi, Nigeria. All histologically confirmed melanoma cases diagnosed between January 2021 and December 2025 were reviewed. Demographic, clinical, and histopathologic variables including anatomic site, histologic subtype, Breslow thickness, Clark level, ulceration, mitotic rate, lymphovascular invasion, tumour necrosis, and margin status were analysed descriptively using SPSS version 25.

Results

Twelve patients contributed thirteen melanoma specimens during the study period. Patients ranged from 34 to 78 years, with a mean age of 54.3 ± 14.9 years. There was equal sex distribution. Acral sites predominated, accounting for 58.3% of cases, while acral lentiginous melanoma was the most common histologic subtype (53.8%). All cutaneous melanomas demonstrated advanced tumour thickness within the pT4 category, with Breslow thickness ranging from 5 mm to 11 mm. Clark level V predominated (69.2%), and ulceration was present in 53.8% of cases. Mitotic activity ranged from 2 to 5 mitoses/mm², with 3 mitoses/mm² being most frequent. Additional adverse features included lymphovascular invasion (15.4%), microsatellites (7.7%), tumour necrosis (30.8%), and amelanotic morphology (30.8%). Most tumours were staged as T4b (53.8%).

Conclusion

Melanoma in this Southeast Nigerian cohort was characterized by acral predominance, advanced tumour thickness, and frequent ulceration, reflecting persistent late presentation and high-risk pathology. Strengthening clinical awareness of acral melanoma, promoting early biopsy of suspicious lesions, and standardizing pathology reporting practices may improve melanoma diagnosis and prognostic assessment in Nigerian settings.

Malignant melanoma, acral lentiginous melanoma, Breslow thickness, ulceration, histopathology, Nigeria, prognostic factors, skin cancer, melanoma staging, sub-Saharan Africa

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