An 81-years-old woman presented multiple mucosa ulcers with a chief complaint of pain during wearing the lower denture. She had been wearing upper and lower complete dentures for five months, and received multiple drugs for the treatment of angina pectoris, constipation, neurosis, hypertension and arthritis (calcium channel blockers, furosemide, captopril, nonsteroidal anti-inflammatory agents and penicillamine, respectively), but no history of immune-diseases and viral infection symptom. The present lesion was primarily diagnosed as traumatic ulcer, candidiasis and lichen planus in the clinical observation, thereby conservatively treated with denture relining, antifungal agent, and steroidal agent. However, the ulcer lesion was not healed for two months and rather increased in size. With the diagnosis of viral infection the immunohistochemical (IHC) staining of IL28 and E6, and polymerase chain reaction (PCR) using herpes simplex virus (HSV)-1 primer sets was done but entirely showed negative reaction. Therefore, with the patient’s medical history and IHC findings exhibiting strong positive reaction of CD3 and CD28, but rare/weak reaction of NFkB, CD20, IgK and p38, the ulcer lesion was finally diagnosed as drug-induced pemphigoid ulceration which was not an inflammatory granulomatous lesion but related to the retrogressive acantholytic degeneration of epithelial cells caused by multiple drug abuse.

53 years old female showed repeated ulceration of labial gingival mucosa at upper and lower anterior teeth, which was a partly desquamated and erythematous lesion. The lesion was slightly extended into vestibule and buccal mucosa in oral cavity, but the similar lesion was not found in other organs by medical inspection. The incisional biopsy including the border of the ulcerated mucosa and normal mucosa showed a severely inflamed mucosa, of which epithelium was gradually detached from the underlying conective tissue, so that it was diagnosed as a mucous membrane pemphigoid (MMP) pathologically. The epithelium was thinned, almost lost its rete pegs, and the basement membrane was completely distorted by the epithelial detachement. The inflammatory cell infiltration was mainly composed of small round cells and plasma cells. Immunohistochemistry was performed to know the expression of pathogenetic proteins using antisera of Igk, E-cadherin, laminin a5, elafin, and eIF5A. The basement membrane at the epithelial detachment was condensely positive for Igk, and the involved epithelium became atrophic but showed consistently positive reaction of matrix proteins and protein translation factor, i.e., E-cadherin, laminin a5, elafin, and eIF5A similar to the adjacent normal mucosa continuous to the MMP lesion. The Igk was also diffusely deposited on the basement membrane of nearby normal mucosa. Many plasma cells infiltrated around the lesion were strongly positive for Igk in their cytoplasms. Therefore, we suggest that the MMP be characterized by the deposition of Igk on the basement membrane of the detached epithelium in the absence of no other pathognomic changes of molecular events.