Temporal dermoid cyst with a partial dermal sinus tract.

BACKGROUND: Cranial dermal sinuses are rare and occur most frequently in the posterior fossa and along the midline. Likewise, supratentorial dermoid cysts are very uncommon.

METHOD: We report a unique case of an adult female patient with both a supratentorial dermoid cyst and an incomplete dermal sinus tract.

RESULTS: The patient is a 31-year-old female, who presented with a new onset complex partial seizure. Neuroimaging and surgery revealed a right superior temporal dermoid cyst with an associated dermal sinus tract. Furthermore, the dermal sinus tract was incomplete and had no cutaneous manifestations.

CONCLUSION: We present a rare patient with an off midline supratentorial dermoid cyst associated with a uniquely incomplete cranial dermal sinus tract. The dermal sinus tract involved the bone, dura and intradural compartment, without involving the overlying skin. This represents a novel variant in the spectrum of cranial dermal sinus abnormalities.