Purpose

Heterotopic neural tissue within the orbit is rare and most frequently reported in paediatric patients or in association with midline craniofacial anomalies. True cerebellar heterotopia in this location is exceptionally uncommon, with only a few cases described in the literature.We present a 36-year-old woman with a lifelong history of intermittent, painless, left-sided chemosis and subtle periorbital asymmetry. Examination revealed 2mm of proptosis with mild inferior scleral show and lower eyelid asymmetry. Computed tomography demonstrated a well-defined, largely extraconal superolateral left orbital mass, isodense to brain parenchyma, without calcification or intracranial communication. Magnetic resonance imaging showed iso- to hypointense signal on T1, heterogeneous T2 hyperintensity, and patchy enhancement without diffusion restriction, favouring a developmental choristoma.The mass was debulked via an upper lid skin-crease incision without complication. Histopathology revealed mature cerebellar cortex with a characteristic triphasic laminated architecture comprising molecular, Purkinje cell, and granular layers, without cytological atypia or immature elements. Immunohistochemistry confirmed GFAP and synaptophysin positivity, consistent with mature neuroglial differentiation.This case represents an unusual adult presentation of biopsy-proven orbital cerebellar heterotopia. The absence of a skull base defect favours aberrant neuroectodermal sequestration during embryogenesis over a regressed encephalocele mechanism. Awareness of this diagnosis is important to avoid misclassification as a vascular malformation or dermoid cyst, and to guide appropriate surgical management.

---

Methods

.

---

Results

.

---

Conclusion

.

---

Additional Authors

First name	Last name	Base Hospital / Institution
Adil	Khan	Moorfields Eye Hospital
Alan	Ramsey	Moorfields Eye Hospital
Kaveh	Vahdani	Moorfields Eye Hospital
David	Verity	Moorfields Eye Hospital
Geoff	Rose	Moorfields Eye Hospital

↑ Back to top