A Hole in the Head: An Intradiploic Epidermoid Cyst With A Calvarial Defect

Epidermoid Cyst With Erosion Into the Calvarial Intradiploic Space

“…Computed tomography (CT) scan and/or MRI are recommended preoperative imaging modalities. 1–3 On computed tomography, these epidermoid cysts present as nonenhancing hypodense osteolytic lesions causing widening of the diploic space and preferential erosion of the inner table. 1,2 In this case, the outer table was destroyed, whereas the inner table was preserved.…”

“…4 Dermatologic surgeons should be aware of the possible intracranial extension with these tumors and have a low threshold to consult with or refer to neurosurgery for any tumors penetrating the inner table of the calvarium, including those with intracranial expansion and dural invasion. 3…”

“…2 Complete biodegradability has been documented in at least 12 weeks with PDO microspheres, but may be vastly more protracted with PDO threads, up to 180 days or more. 2,3 Polydioxanone thread procedures are associated with transient, self-limited side effects, including erythema, edema, ecchymosis, and infection. Skin dimpling, contour irregularity, visible threads, and thread extrusion were the most common complications in a retrospective review.…”

“…1,2 Only a few cases of intradiploic epidermoid cysts resulting in cranial bone defects have been reported in the dermatologic surgery literature. 3 This unusual case highlights the attempt to excise an epidermoid cyst on the scalp by dermatologic surgery, who was met with concern for intracranial extension during the initial procedure.…”

“…1,2 Intradiploic epidermoid cysts are a rare subtype of epidermoid cysts that originate between two tables of cranial bone and connect the intracranial space to the overlying skin. 1,3 They occur because of defects in the separation of the neuroectoderm during the formation of the neural tube, leading to sequestration of ectodermal remnants within the cranial bones. 1 They can also result from introduction of epidermal elements at the time of trauma.…”