Case Number : Case 1067 - 25th July Posted By: Guest

Lichen planus-like keratosis.

LPLK

Lichen planus-like keratosis. Hemorrhage?

Agree with Lichenoid keratosis, if solitary lesion.

Agree with the above, but would do melanocytic markers.

[quote name='I. Abdul-kadir' timestamp='1406283705']
Agree with the above, but would do melanocytic markers.
[/quote]

At first glance, this lesion looks lichenoid keratosis, but away from the lichenoid infiltrate there are lentiginous epithelioid melanocytes, albeit non-confluent. Bearing in mind this lesion is located on the back of a middle-aged man and a Dr. Carr’s comment in a [url="https://dermpathpro.com/spot-diagnosis-1/_/2013-spot-diagnoses/april-2013/case-734-9-apr-r757?st=0#comment_2859"]past spot diagnosis[/url], I think the brown pigment within the lichenoid infiltrate might raise suspicion of melanoma.

All agreed. I reported this as a lichen planus-like keratosis (adjacent solar lentigo) and reproduce here the link for those of you who only have the free access. Many thanks to Dr Rocha for reminding me of these comments.

Posted 10Apr13 in Discussion to Case 734:
[color=#1C2837][font=arial, verdana, tahoma, sans-serif][size=4]In answer to Dr Rocha's question "LPLK" is not a diagnosis it is a reaction pattern.[/size][/font][/color]
[color=#1C2837][font=arial, verdana, tahoma, sans-serif][size=4]Solar lentigo is possibly the most common association but it is basically a lichenoid reaction to a superficial lesion the nature of which almost by definition is uncertain. It could be seen in reaction to pre-existing actinic keratosis, thin seborrhoeic keratosis, thin SCC and indeend thin melanoma. Some pathologists recommend examination of multiple levels in all cases and I have heard some experts stating that a MelanA should be done on all cases. I am very wary about making the "diagnosis" of LPLK in a partial specimen e.g. punch biopsy and I emphasise it is a non-diagnosis / reaction pattern. Obviously if there is any clinical concern about a lesion it should be excised with clear margins in such cases. My comments may be conservative but unfortunately I have myself missed a thin melanoma (on punch biopsy due to brisk inflammatory reaction) that had very sparse histiocyte-like dermal cells and unfortunately the same lesion was punch biopsied a year latter and reported by another pathologist as LPLK (when on review there was more obvious SSMM). The final diagnosis of melanoma was delayed for two years in that particular case. All that said I don't personally automatically do MelanA myself on all cases I am very selective but I do automatically examine multiple levels in an attempt to make a specific diagnosis.[/size][/font][/color]