Perineural spread in a case of pituitary adenoma

Perineural spread (PNS) is commonly observed with head-and-neck malignancies such as squamous cell carcinoma, adenoid cystic carcinoma, and nasopharyngeal carcinoma. Pituitary adenomas are not known to have PNS, and only a single case has been reported previously. We report a case of a 27-year-old woman who presented with the complaints of headache and visual disturbances. Magnetic resonance imaging of the pituitary showed a macroadenoma extending along the trigeminal nerve through the foramen ovale, the Meckel’s cave, the prepontine area, and the superior orbital fissure on the right. Histopathology of the postresection specimen revealed a pituitary adenoma. Imaging features of PNS include thickening with the diffuse enhancement of the nerve, nodularity, enlargement/erosion of the foraminae, effacement of the perineural fat pad, and denervation changes in the muscles. PNS in a tumor has to be actively searched for and reported, as it alters the prognosis and the management.