Acantholysis

Introduction

• The term acantholysis  is derived from the Greek words akantha, meaning a thorn or prickle, and lysis, i.e. loosening.
• Acantholysis is the term used to describe loss of cohesion between  keratinocytes, due to breakdown of intercellular bridges (eg- Desmosomes). This makes the normally polygonal keratinocytes  circular (Circular keratinocytes= Acantholytic cells). It results in the formation of intraepidermal clefts, vesicles and bullae.

Although acantholysis may occur at any level of the epidermis, the location of the blister is often used as a clue to the underlying disorder; for example, superficial (subcorneal) acantholysis favors pemphigus foliaceus, while acantholysis in the deeper aspects of the epidermis is more characteristic of pemphigus vulgaris

Acantholytic cell in pemphigus- Yellow arrow
(Ref: IJDVL. Seshadri et al.)

Primary Acantholysis

Acantholysis is either due to direct injury to desmosomes (eg: Pemphigus, bullous impetigo, staphylococcal scalded skin syndrome SSSS) or due to hereditary defects in their construction (eg: Darier's disease and Hailey-Hailey disease). Thus, in these diseases, acantholysis is the primary event leading to the formation of intra-epidermal cavities and hence the manifestations of the disease.  Eg: pemphigus, Darier’s disease etc 

Secondary Acantholysis

The acantholysis is secondary to alteration or damage to keratinocytes by various factors. In other words, keratinocytes are injured first followed by subsequent disintegration of desmosomes. Eg: In herpes, intraepidermal vesicle is secondary to ballooning degeneration of keratinocytes causing circular keratinocytes. Tzanck cells are multinucleated giant cells seen after fusion of individual acantholytic cells and is characteristically seen in herpes.

MCQs

1) A middle aged female presents with flaccid bullae in skin and oral erosions. Histopathology shows intra-epidermal acantholytic blisters. The most likely diagnosis is (PGI 05)

a) Pemphigus vulgaris

b) Bullous pemphigoid

c) Dermatitis herpetiformis

d) Epidermolysis bullosa

e) Pemphigus foliaceous

Ans: a

2) A female presents with persistent painful oral erosions with acantholytic cells. Most likely diagnosis (AI 08)

a) Dermatitis herpetiformis

b) Bullous pemphigoid

c) Pemphigus vulgaris

d) Epidermolysis bullosa

Ans: c

3) Acantholysis is seen in (PGI 99)

a) Bullous pemphigoid

b) Dermatitis herpetiformis

c) Hailey-Hailey disease

d) Darier’s disease

e) Pemphigus vulgaris

Ans: c.d.e

4) Acantholysis is seen in (AI 95)

a) Epidermis

b) Dermis

c) Dermoepidermal junction

d) Subcutaneous tissue

Ans: a

5) Acantholysis is due to destruction of (AIIMS 97)

a) Epidermis

b) Dermis

c) Basement membrane

d) Intercellular susbstance

Ans: d

6) Acantholytic cells are (SGPGI 01)

a) Epidermis cells

b) Plasma cells

c) Keratinocytes

d) Giant cells

Ans: c

7) Acantholytic cells are (PGI 96)

a) Cells with hyperchromatic nuclei and perinuclear halo

b) Cells with hypochromatic nuclei and perinuclear halo

c) Multinucleate cells

d) None

Ans: a

8) A 50 year old man with flaccid bullae and oral ulcers. Smear from skin lesions would show (AI 96)

a) Tzanck cells

b) Acantholytic cells

c) Necrosis

d) Koilocytes

Ans:b