In orofacial granulomatosis, sections show oral mucosa with a sparse inflammatoryinfiltrate and mild oedema (figure 1). Higher power examination shows ectasia of lymphatics next to rare loose granulomas (figures 2-4, arrows indicate granulomas). Sometimes the granulomas may be difficult to find and extensive serial sectioning of the biopsy is recommended.
Figure 1
Figure 2
Figure 3
Figure 4
Special studies of orofacial granulomatosis
Special stains for microorganisms may be performed to rule out an infection, given the granulomatous nature of the infiltrate.
Differential diagnosis of orofacial granulomatosis
Melkersson-Rosenthal syndrome: Shows the exact same pathology but clinically also shows facial nerve palsy and a “scrotal” tongue.
Crohn disease: Oral involvement with Crohn disease will be histologically identical. Clinical correlation is needed.
Sarcoid: Sarcoidal granulomas tend to be more overt and larger but some cases can be difficult/impossible to distinguish from orofacial granulomatosis.
References
Pathology of the Skin (Fourth edition, 2012). McKee PH, J. Calonje JE, Granter SR