12.5 y/o neutered, male terrier cross, presented with what was diagnosed as a nasty pyoderma on his chin 3 years ago - and which has never completely resolved with repeated long courses of antibiotics. Unfortunately never been involved directly with the case in order to report in house cytology findings, but biopsy results as follows (from july this year on chin). Also now has lesions on eye and nail bed as you can see in the pictures - and the Vet is wondering if they could be related. Any suggestions?

CLINICAL HISTORY

Lesion from the lower right caudal lip from S***e.

HISTOLOGY

One section from a single biopsy is examined. This corresponds to a portion of haired skin. There is an area of ulceration with intense confluent mixed inflammation formed by neutrophils, histiocytes, lymphocytes and plasma cells. Beneath the ulceration the apocrine glands are dilated. There are some areas of interstitial fibroplasia. The inflammation is around some of the follicular adnexal units. Within the ulceration there are a few apoptotic keratinocytes surrounded by lymphocytes.

COMMENT
There is moderate intense superficial inflammatory process with ulceration. The cause of the ulcer is not apparent. Morphologically there are some features compatible with erythema multiforme, but the amount of necrosis present is limited. Sometimes localised erythema multiforme-like lesions are a consequence of topical medications or superficial adverse reaction. Generalized lesions of erythema multiforme may affect other mucosal sites and the skin.