Acantholytic

Acantholytic is an adjective used in pathology to describe tissue in which acantholysis has occurred, a process in which epidermal keratinocytes lose their intercellular connections, particularly desmosomal junctions, leading to impaired cell cohesion and the formation of clefts or vesicles within the epidermis.

Acantholysis most commonly affects the epidermis of the skin and mucous membranes and is a hallmark of several diseases, especially within the pemphigus group. It results from disruption of desmosomes, often due to autoantibodies targeting desmogleins or other adhesion proteins. In pemphigus vulgaris, antibodies to desmoglein 3 (and sometimes desmoglein 1) cause suprabasal acantholysis; pemphigus foliaceus involves desmoglein 1 and typically shows more superficial separation. Other conditions with acantholysis include Darier disease, where genetic defects in calcium homeostasis lead to both acantholysis and dyskeratosis, and transient acantholytic dermatosis (Grover disease).

Histopathologically, acantholysis yields intraepidermal or suprabasal clefts with dissociated keratinocytes. The basal layer often remains attached to the basement membrane, producing a characteristic “tombstone” appearance of basal cells. The overlying roof of the cleft may contain rounded, discohesive keratinocytes (acantholytic cells). The pattern and level of acantholysis help distinguish among associated diseases and guide diagnostic testing, such as immunofluorescence in pemphigus.

See also: acantholysis, desmosomes, pemphigus, Darier disease.