Giant melanoacanthoma mimicking malignant melanoma

Area of Science:

• Dermatology
• Pathology
• Oncology

Background:

• Melanoacanthoma is a rare pigmented variant of seborrheic keratosis.
• Distinguishing it from malignant melanoma is crucial for appropriate patient management.

Purpose of the Study:

• To report a unique case of massive melanoacanthoma.
• To highlight diagnostic challenges and confirm findings through dermoscopy and histopathology.

Main Methods:

• Clinical examination of a large, pigmented, verrucous plaque.
• Dermoscopic evaluation to assess for malignant melanoma features.
• Histopathological analysis of skin biopsy for definitive diagnosis.
• Surgical excision and skin grafting for treatment.

Main Results:

• A 65-year-old male presented with a 10 cm x 5 cm, painful, progressively growing lesion on his lower back.
• Dermoscopy revealed features consistent with benign pathology, excluding malignant melanoma.
• Histopathology confirmed melanoacanthoma with basaloid cells and dendritic melanocytes.

Conclusions:

• Massive melanoacanthoma can clinically mimic malignant melanoma.
• Dermoscopy and histopathology are essential for accurate diagnosis.
• Surgical excision is an effective treatment modality for large lesions.