Large-cell acanthoma is a solar lentigo.

Area of Science:

• Dermatopathology
• Cutaneous Oncology

Background:

• Distinguishing between various benign keratinocytic proliferations can be challenging.
• Solar lentigo, reticulated seborrheic keratosis, and lichen planus-like keratosis are common skin conditions.
• Large-cell acanthoma is a less common entity with overlapping features.

Purpose of the Study:

• To clarify the relationship between large-cell acanthoma, solar lentigo, reticulated seborrheic keratosis, and lichen planus-like keratosis.
• To determine if large-cell acanthoma represents a distinct entity or a variant of another condition.
• To establish the potential evolutionary pathway of these keratinocytic lesions.

Main Methods:

• Histopathological examination of 54 specimens each of large-cell acanthoma, solar lentigo, reticulated seborrheic keratosis, and lichen planus-like keratosis.
• Clinical and biological assessments were performed.
• Comparative analysis of morphological and cellular features.

Main Results:

• Large-cell acanthoma shares significant clinical, histopathological, and biological characteristics with solar lentigo.
• Solar lentigo, including its large-cell variant, demonstrates features consistent with an earlier stage of development.
• Reticulated seborrheic keratosis and lichen planus-like keratosis appear to represent later stages in the evolution from solar lentigo.

Conclusions:

• Large-cell acanthoma is histopathologically and biologically a variant of solar lentigo.
• Solar lentigo is identified as a precursor or intermediate stage in the development of reticulated seborrheic keratosis and lichen planus-like keratosis.
• This finding refines the understanding of the spectrum of keratinocytic skin lesions.