Acantholysis involves (is seen in):
**Core Concept**
Acantholysis is a process in which there is loss of intercellular connections between keratinocytes, leading to the separation of these cells from each other. This phenomenon is a hallmark of pemphigus, a group of autoimmune skin diseases.
**Why the Correct Answer is Right**
Acantholysis occurs due to the breakdown of desmosomal connections between keratinocytes. Desmosomes are specialized adhesion complexes that hold these cells together, and their disruption leads to the characteristic blistering seen in pemphigus. This process is mediated by autoantibodies against desmoglein 1 and 3, proteins that are crucial components of desmosomes.
**Why Each Wrong Option is Incorrect**
**Option A:** Acantholysis is not seen in psoriasis, which is characterized by parakeratosis and the accumulation of neutrophils in the epidermis.
**Option B:** Acanthosis is a process of hyperplasia of the epidermis, not the loss of intercellular connections between keratinocytes.
**Option C:** Spongiosis is a condition characterized by the accumulation of water in the epidermis, leading to a spongy appearance, but it is not associated with acantholysis.
**Clinical Pearl / High-Yield Fact**
Acantholysis is a key histopathological feature of pemphigus, and its presence can help differentiate this condition from other blistering skin diseases.
**Correct Answer: D. Pemphigus**