Case Number : Case 1943 - 09 Nov Posted By: Iskander H. Chaudhry

Cheilitis granulomatosa. There is dermal edema with mononuclear cell infiltrate. Obvious epithelioid cell granulomas may not be seen in all biopsies

I was thinking instead of a mucous membrane pemphigoid/cicatricial pemphigoid...

It is upper cutaneous lip. A lot depends on the clinical. Single lesion or rash, appearance, distribution, medical and medication history etc. If rash, it looks like subepidermal clefting with mixed dermal infiltrate including lymphocytes, plasma cells, neutrophils, and occasional eosinophils. Medication reactions such as bullous drug eruption and bullous fixed drug are more likely. Age is slightly younger for bullous pemphigoid, but BP is in the differential. Eos negate bullous SLE. Phototoxic, paraneoplastic, bullous bite reaction are all in the differential, so are other 100 things I can't think of or don't know about!

I agree with Vparekh. I feel like there is something else going on here that I don't know about. My differential would be large as well.

Many thanks for the comments. The Direct immunofluorescence (DIF) of peri-lesional mucosa showed linear deposition of IgG, C3, and IgA along the basement membrane zone in keeping with Mucous membrane pemphigoid (MMP). In light of the IMF result the histology does fit although on its own it is difficult to discern from this biopsy! 

Nice case!