Ocular adnexal pseudo-cyst formation as a characteristic feature of perineural spread in squamous cell carcinoma

To report the clinical features in a series of patients with perineural spread of squamous cell carcinoma involving periorbital nerves that presented with clinical and/or imaging evidence of pseudo-cystic transformation along the involved nerves.

A noncomparative, retrospective chart review of the clinical and imaging findings of patients attending a regional orbital surgery department between 1998 and 2005, presenting with a pseudo-cystic orbital mass on clinical examination and/or imaging, which proved to be due to perineural squamous cell carcinoma on histopathology.

The study included 8 male patients with a mean age at referral of 66 +/- 11 years. All cases had associated cutaneous squamous cell carcinoma involving the face or scalp, and, in 4 cases, the primary tumor could be identified in the vicinity of the affected orbit. The duration of the symptoms varied from 5 weeks to 9 years (24 +/- 36 months). Altered sensation, including formication and hypo-esthesia in the V1 and V2 trigeminal division, motor nerve palsies, and ptosis in conjunction with a palpable periorbital mass, were the most common presentations. The cystic tumor deposits were assessed histologically with both hematoxylin and eosin and immunoperoxidase stains (S100 protein for neural structures identification and MNF116 as a keratin marker). This demonstrated malignant squamous epithelium both within and around the wall of the tumor deposit and, in continuity, within the nerve running through the lesion. Some nerves showed substantial areas of fibrosis, representing obliteration of the nerve structure caused by involvement by tumor. Treatment modalities included surgical debulking, exenteration, radiotherapy, and combined chemo-radiotherapy. Mean follow-up was 29 +/- 23 months. Eight patients (87.5%) remain alive, and five of them show no evidence of disease. One patient died after progression of the malignancy.

The presence of a cystic lesion in association with sensory or motor deficit in the periorbital region should suggest a diagnosis of perineural spread from a cutaneous squamous cell carcinoma. Because these patients may present to the ophthalmologist first, an awareness of this entity is of critical importance to avoid the delayed diagnosis seen in half of our cases.