Indian Journal of Dermatology
: 2022  |  Volume : 67  |  Issue : 3  |  Page : 316-

Porokeratosis and lichen planus: Co-localisation or isotopic response or koebner's phenomenon?

Jayanti Datta1, Sk Shahriar Ahmed2, Sudipta Roy1, Arghyaprasun Ghosh1, Anupam Das3,  
1 Department of Dermatology, Bankura Sammilani Medical College, Bankura, West Bengal, India
2 Department of Dermatology, Calcutta National Medical College, Kolkata, West Bengal, India
3 Department of Dermatology, KPC Medical College and Hospital, Kolkata, West Bengal, India

Correspondence Address:
Anupam Das
Department of Dermatology, KPC Medical College and Hospital, Kolkata, West Bengal

How to cite this article:
Datta J, Ahmed SS, Roy S, Ghosh A, Das A. Porokeratosis and lichen planus: Co-localisation or isotopic response or koebner's phenomenon?.Indian J Dermatol 2022;67:316-316

How to cite this URL:
Datta J, Ahmed SS, Roy S, Ghosh A, Das A. Porokeratosis and lichen planus: Co-localisation or isotopic response or koebner's phenomenon?. Indian J Dermatol [serial online] 2022 [cited 2022 Dec 5 ];67:316-316
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Full Text


Co-localisation of diseases in dermatology has always remained deceptive and a difficult to crack puzzle. Co-existence of lichen planus (LP) with a number of dermatological diseases is well documented.[1] We hereby report a case of LP co-localising with porokeratosis of Mibelli near the angle of the lip in a middle-aged woman. The case is being reported for the unusual site and association.

A 30-year-old woman presented with a plaque surmounted by erosion, crusting and haemorrhage, 5 cm in longest diameter at the left angle of the mouth, present for the preceding 10 days [Figure 1]a. It was a small vesicle to start with, gradually progressing to form a bulla in 2–3 days, which ruptured the next day to attain the present status. On close cutaneous examination, the margin of the lesion was found to be serpiginous, raised, keratotic, ridge-like with a central groove. Mucosal examination showed reticulate violaceous patches over buccal mucosa and tongue. On further enquiry, the woman gave a history of this lesion being present for the last one year, but it was ignored till the erosion appeared on its surface. There were no similar lesions elsewhere.{Figure 1}

All the routine blood parameters were within normal limits. She was non-reactive for HIV. Chest X-Ray and mantoux test were normal. Biopsy from the elevated borders of the lesion showed orthokeratotic hyperkeratosis, acanthosis, prominent granular cell layer, saw-toothing of rete ridges, band-like lymphoplasmacytic infiltrate at the dermo-epidermal junction, focal basal cell degeneration and pigment incontinence [Figure 1]b. A column of parakeratotic cell invaginating into the epidermis (cornoid lamellae) with the absence of granular layer beneath was noted on one side of the specimen [Figure 1]c. LP was treated with prednisolone 40 mg for 2 weeks and symptoms improved within 2–3 weeks, the serpiginous rim persisted and became more obvious [Figure 1]d.

Co-localisation of LP has been described with sebaceous cyst,[1] generalised morphea and lichen sclerosus,[2] Riehl's melanosis,[3] vitiligo[4] and others. In our patient, typical margin of porokeratosis was clinically evident, but the central area of the plaque was intriguing. We thought of localised pemphigus vulgaris as oral ulceration was also present initially which later developed as a reticular violaceous patch suggesting oral lichen planus. Orificial tuberculosis was another differential. Histopathological examination confirmed the presence of both LP and PK. The chronology of porokeratosis developing over the lesion of lichen planus in its centre points towards isotopic response. The occurrence of LP over a pre-existing lesion of porokeratosis might be explained by Koebner's phenomenon due to constant trauma occurring at the angle of mouth. A case of co-localisation of porokeratosis and lichen planus has been reported over the lower limbs.[5] Our case is unique because of the unusual location, and the probability of Koebner's phenomenon behind the development of the association.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

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