BACKGROUND: Pyostomatitis-pyodermatitis vegetans is an uncommon condition 
associated with chronic inflammatory bowel disease in 75% of the cases, usually 
hemorrhagic rectocolitis.
CASE REPORT: A 48-year-old man was referred for recent development of pustulous 
lesions of the lips and buccal mucosa and weight loss. He complained of 
abdominal pain and intermittent diarrhea which had persisted for more than one 
year. During the last three months, a pseudotumoral plaque with a pustulous rim 
had developed over the two distal phalanxes of the right middle finger in 
association with ungueal lysis and nodular, vegetating and crusted lesions on 
the lateral aspect of the left arm. Small pustules covered the entire buccal 
mucosa excepting the tongue and the glans forming a typical snail trace aspect. 
Bacterial and mycological samples were negative. The histology reports for skin 
and mucosa were similar: epithelial hyperplasia, intra- and subepithelial 
granulocyte micro-abscesses and polymorphous infiltration of the superficial 
derma with numerous neutrophils and eosinophils. There was a discrete 
interkeratinocytic fluorescence at direct immunofluorescence but indirect 
immunofluorescence was negative. Anti-desmogleine 1 immunolabeling showed 
typical normal skin uptake and immunotransfer was negative. Digestive tract 
endoscopy and histopathology examination of the bowel specimens confirmed the 
diagnosis of Crohn's disease. Clinical manifestations improved dramatically with 
prednisone.
DISCUSSION: This case of pyostomatitis-pyodermatitis vegetans involved several 
aspects rarely reported in the literature: a) the cutaneomucosal signs were 
inaugural; b) the association with Crohn's disease; c) the presence of lesions 
to the genital mucosa; d) the unusual localization of the inaugural skin 
manifestations. This clinical entity has now been clearly distinguished from 
pemphigus vegetans. There was however a long debate on the similar clinical, 
histological and even immunological expressions. We suggest that 
pyostomatitis-pyodermatitis vegetans belongs to the spectrum of neutrophilic 
dermatoses and other authors even propose it is a clinical form of pyoderma 
gangrenosum.