Acanthosis means ?
**Core Concept**
Acanthosis refers to the thickening of the stratum spinosum layer of the epidermis, resulting in an increased number of skin papillae. This condition is often associated with skin diseases such as psoriasis and eczema.
**Why the Correct Answer is Right**
Acanthosis is characterized by the hyperplasia of the epidermal cells, particularly in the stratum spinosum layer. This leads to an increased number of skin papillae, which are small projections of the dermal layer into the epidermis. The thickening of the epidermis is often accompanied by an increase in the number of dermal papillae, leading to the characteristic appearance of acanthosis under microscopic examination.
**Why Each Wrong Option is Incorrect**
**Option A:** Hyperkeratosis refers to the thickening of the stratum corneum layer of the epidermis, which is different from acanthosis.
**Option B:** Eczema is a skin condition that can lead to acanthosis, but it is not a synonym for acanthosis.
**Option C:** Psoriasis is a skin condition that can cause acanthosis, but it is not a definition of acanthosis.
**Clinical Pearl / High-Yield Fact**
Acanthosis is often seen in conjunction with other skin changes, such as parakeratosis (retention of nuclei in the stratum corneum) and hypergranulosis (thickening of the granular layer).
**Correct Answer:** C. Thickening of the stratum spinosum layer of the epidermis.