Idiopathic hypertrophic cranial polyneuropathy: a rare cause of orbital pain

Hypertrophic cranial polyneuropathy (HCP) is sporadically encountered in clinical practice. Aetiologies of HCP have been classified as autoimmune, infectious and demyelinating. However, an accurate diagnosis remains elusive in some cases despite rigorous investigations. These cases represent idiopathic HCP. Given the high clinical variance in presenting symptoms, HCP often leaves medical practitioners in a diagnostic quandary. Here, we seek to expand current knowledge by reporting the first documented case of idiopathic HCP presenting atypically with unilateral orbital pain and exclusively involving the bilateral trigeminal nerves.