case_images: PMC7093687_01
case_images: Clinical features. (A) Hemorrhagic crust more prominent in the lower lip. (B)
  Buccal mucosa with extensive vesicular lesions with erythematous
  borders.
case_images: 10.1177_2324709620914796-fig1.jpg
case_images: PMC7093687_01_10.1177_2324709620914796-fig1.jpg
case_images: fig1-2324709620914796
case_images: The physical examination revealed hemorrhagic crust more prominent in the lower lip, showing cracking and fissuring with blood encrustation (Figure 1A). Oral mucosa examination showed extensive vesicles with erythematous borders scattered in hard palate, mucosa, and gums (Figure 1B).
case_images: Histopathologic findings. (A) Ulcer bed composed of granulation tissue and
  covered by a fibrin clot. A diffuse acute and chronic inflammatory cell
  infiltrate is appreciated throughout the subjacent connective tissue stroma
  (hematoxylin and eosin [H&E]; 100x). (B) Mildly parakeratotic stratified
  squamous epithelium overlying fibrous connective tissue. A patchy
  predominately chronic inflammatory cell infiltrate is noticed, focally
  aligned along the epithelial-connective tissue interface (H&E;
  100x).
case_images: 10.1177_2324709620914796-fig2.jpg
case_images: PMC7093687_01_10.1177_2324709620914796-fig2.jpg
case_images: fig2-2324709620914796
case_images: The ulcer bed was covered by a fibrin clot composed of enmeshed erythrocytes, neutrophils, and lymphocytes (Figure 2A). Numerous ectatic endothelial-lined vascular channels were noticed throughout the subjacent connective tissue stroma, which exhibits a diffuse acute and chronic inflammatory cell infiltrate (Figure 2B).