Acanthosis refers to a thickening of the skin's outer layer. More specifically, it's an increase in the thickness of the stratum spinosum, a layer of the epidermis, due to an overgrowth (hyperplasia) and sometimes an increase in cell size (hypertrophy) of its cells. This is often accompanied by hyperkeratosis, which is a thickening of the stratum corneum, the outermost layer of skin. While often benign, it can be a sign of underlying health conditions.
Understanding Acanthosis: A Deeper Look
Several sources define acanthosis in similar ways, emphasizing the increase in the thickness of the stratum spinosum and sometimes the stratum corneum. This thickening is caused by an increase in the number (hyperplasia) and sometimes the size (hypertrophy) of the cells within these layers.
- Hyperplasia: An increase in the number of cells.
- Hypertrophy: An increase in the size of cells.
- Hyperkeratosis: A thickening of the stratum corneum (the outermost layer of the skin).
Acanthosis is not always visible, and its appearance can vary depending on the underlying cause. It's important to note that many sources refer to acanthosis nigricans, a specific type of acanthosis that presents as dark, velvety patches of skin in body folds, often in the armpits, groin, and neck. This is a more visible manifestation.
Examples of Acanthosis:
- Acanthosis nigricans: A dark, velvety skin condition often associated with underlying health issues like insulin resistance or certain cancers. This is a common type of acanthosis.
- Acanthosis in psoriasis: Acanthosis is also seen in conditions like psoriasis, where the thickening of the skin is part of the disease process.
Important Considerations:
A diagnosis of acanthosis alone isn't sufficient for definitive medical treatment. The underlying cause must be determined. A biopsy may be necessary to distinguish acanthosis from other skin conditions. A "benign acanthotic lesion" on a biopsy report requires further clinical evaluation to determine the correct diagnosis and management strategy.
