Acantholytic cells are :
**Core Concept**
Acantholytic cells refer to the characteristic pathological finding in autoimmune bullous diseases, specifically pemphigus vulgaris, where there is a loss of intercellular connections between keratinocytes in the epidermis. This disruption is due to the autoantibody-mediated destruction of desmogleins, a family of adhesion molecules crucial for cell-to-cell adhesion.
**Why the Correct Answer is Right**
In pemphigus vulgaris, the autoantibodies target desmoglein 3, a specific type of desmoglein that is predominantly expressed on the surface of keratinocytes. The binding of these autoantibodies to desmoglein 3 triggers the activation of the complement system and the subsequent release of proteolytic enzymes, leading to the breakdown of the intercellular connections between keratinocytes. As a result, the cells separate from each other, forming acantholytic cells, which are characteristic of this disease.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because acantholytic cells are not a feature of psoriasis, which is characterized by parakeratosis, thickening of the epidermis, and an inflammatory infiltrate.
**Option B:** This option is incorrect because acantholytic cells are not a hallmark of lichen planus, which is characterized by basal cell degeneration, a band-like inflammatory infiltrate, and the presence of colloid bodies.
**Option C:** This option is incorrect because acantholytic cells are not a characteristic finding in seborrheic dermatitis, which is characterized by a superficial perivascular infiltrate and a distinctive scaly appearance.
**Clinical Pearl / High-Yield Fact**
Acantholytic cells can be identified under the microscope as rounded, isolated keratinocytes that have lost their intercellular connections, often with a pyknotic nucleus and a clear cytoplasm.
**Correct Answer:** D.