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focal acantholytic dyskeratosis

Friday 12 October 2012

Although the term ‘focal acantholytic dyskeratosis’ is often used both for clinically inapparent incidental foci and for clinically apparent solitary lesions with the histological pattern of acantholytic dyskeratosis, some authors restrict its use to its incidental finding in histological sections. This is not an uncommon event.

Ko and colleagues have recently coined the term ‘acantholytic dyskeratotic acanthoma’ for this lesion, apparently on the basis that it is more than an incidental finding, and it often presents clinically as a basal cell carcinoma of the trunk.

The author sees at least one case each week of this phenomenon, whether it be incidental or otherwise.

The term ‘papular acantholytic dyskeratoma’ has been applied to the clinically apparent solitary lesions, and ‘papular acantholytic dyskeratosis’ to the exceedingly rare cases in which multiple lesions have developed on the vulva, perianal area, or penis.

A clinically apparent lesion has also been reported on the lip.

A case reported as ‘congenital acantholytic dyskeratotic dermatosis’ appears to be a variant of papular acantholytic dyskeratosis. There were multiple erosive papules and plaques located on the left thigh, left ankle, and right neck that were present at birth. There was no family history of Darier’s disease and no genetic studies were performed.

Incidental focal acantholytic dyskeratosis is statistically increased in atypical melanocytic lesions.

Microscopy

There is acantholytic dyskeratosis.

Hyperkeratosis is less prominent in incidental lesions than in Darier’s disease.

The "warty dyskeratoma" differ from "focal acantholytic dyskeratoma" by having more prominent villi, clefting, and corps ronds.

Some of the genital and crural cases have a histological resemblance to Hailey–Hailey disease, with marked acantholysis and little dyskeratosis. They belong to the recently recognized acantholytic subset of acantholytic dyskeratosis; another subset features dyskeratosis alone.

In one case of "papular acantholytic dyskeratosis of the anogenital region" immunofluorescence showed intercellular IgG and C3 within the epidermis.

Acantholytic subset

Acantholysis, with little or no dyskeratosis, can be seen as an incidental phenomenon or as a solitary tumor of the skin – acantholytic acanthoma.

This pattern has also been found in multiple papules and as a variant of epidermal nevus with horn-like processes. This latter case was reported as ‘nevus corniculatus’.

A high proportion of the rare genital, crural, and perineal cases referred to as "papular acantholytic dyskeratosis" have had a histological resemblance to Hailey–Hailey disease, with prominent acantholysis and little or no dyskeratosis.

Other cases have resembled acantholytic dyskeratosis.

An appropriate designation for these cases would seem to be ‘acantholytic dermatosis of the genitocrural/perineal region’.

The exact classification of the vulval case with histological resemblance to pemphigus vegetans remains to be determined.

Another case of this entity was reported as warty dyskeratoma. Incidentally, it responded to tazarotenic acid.

Generalized acantholysis is seen in Hailey–Hailey disease. A peculiar form of acantholysis, localized to the acrosyringium, has been reported in several febrile patients. The clinical picture resembled Grover’s disease. The authors proposed the name ‘sudoriferous acrosyringeal acantholytic disease’.

Finally, acantholysis with minimal dyskeratosis can be seen, as an incidental phenomenon, in other disease processes such as pityriasis rubra pilaris and seborrheic keratoses.

Dyskeratotic subset

Although regarded as a variant of epidermolytic acanthoma, the isolated lesion reported as ‘isolated dyskeratotic acanthoma’ is best classified here.

It combined dyskeratotic cells throughout the epidermis with a parakeratotic horn containing large rounded cells at all levels.

The term ‘acquired dyskeratotic acanthosis’ has recently been applied to a case in which multiple maculopapules, 3–8 mm in diameter, developed in sun-exposed areas. There were clusters of parakeratotic cells which appeared eosinophilic to ‘ghostlike’. The epidermis was papillomatous and acanthotic with foci of dyskeratotic keratinocytes.

The proliferation of terms for solitary cases showing acantholysis, dyskeratosis or both, and in variable proportions, is bordering on the ridiculous.

Perhaps prospective authors should attempt consolidation rather than further ‘splitting’.