Intradiploic Dermoid Cyst of the Lateral Frontotemporal Skull: Case Report and Review of the Literature

Abstract

Background: Intradiploic dermoid cysts represent 0.04-0.7% of cranial tumors. Fewer than 20 cases of dermoid cysts occurring in the lateral frontotemporal region with a sinus tract and bony involvement are described, only 7 with intracranial extension. We present the first report of such a lesion arising within the lateral coronal suture. As the literature on this topic grows, the matter of preoperative imaging for soft tissue and bony lesions of the lateral frontotemporal region is evolving, and this report offers a preliminary set of criteria for when imaging is a necessity. Case Report: A 2-year-old male presented with a bony lesion in the right frontotemporal region. Since birth the lesion had grown commensurately with the patient. Examination revealed an immobile hard mass overlying the right coronal suture with no discernable abnormality. Computed tomography demonstrated a cystic lesion without evidence of intracranial extension. Intraoperatively, the exophytic lesion was fully enclosed by bony matrix, interrupting the coronal suture as it approached the pterion. Following resection, pathology revealed an intradiploic dermoid cyst. Conclusion: Intradiploic dermoid cysts occurring within patent cranial sutures away from the midline are rarely described lesions. Complete surgical resection with careful follow-up is the treatment of choice.

Dermoid Cyst of the Prepontine Cistern and Meckel's Cave: Illustrative Case and Systematic Review

“…Dermoid cysts are benign, congenital tumors primarily filled with lipid components, desquamated cells, and keratinaceous debris. 1,4,68,69 These cysts are diagnosed most frequently between the third and fifth decades of life, a finding supported by the cases we reviewed. 1,10,69,70 We found no sex predominance for intracranial dermoid cysts, an observation first described in an earlier study.…”

“…2,8,10,[12][13][14][15]32,55,68,69,71 Evidence supporting this theory includes an affinity of dermoid cysts to develop along the midline. 6,[8][9][10][11][12]15,68,69 Dermoid cysts have also been associated with congenital anomalies (e.g., Klippel-Feil syndrome or agenesis of the corpus callosum). 2,3,13 Others have hypothesized that mesodermal or mesenchymal cells are necessary during the inclusion of the ectoderm.…”

“…Most middle fossa dermoid cysts were resected via a pterional craniotomy. 11,12,32,69,71 Posterior fossa dermoid cysts were often resected via a suboccipital craniotomy. 3,4,10 CPA dermoid cysts were also resected via a standard retrosigmoid approach.…”

“…Closer pathological examination reveals a capsule lined with stratified squamous epithelium. 1,5,7,12,15,69,71 The cystic components contain secretions from sebaceous glands, desquamated material from epithelial cells, keratin, hair follicles, and even teeth, which may explain the common misdiagnosis of teratoma. 1,4,5,7,9,11,12,15,69,71 Teratomas, by definition, must contain non-cutaneous material and can be ruled out by histopathologic evaluation.…”

“…87 Other potential diagnoses may also include arachnoid cysts and cholesterol granulomas. 9,10,69 Arachnoid cysts may be differentiated from dermoid cysts by the heterogeneous appearance of dermoid cysts on imaging. 9,14,15 Diffusion scans may be used to differentiate epidermoid cysts by their greater degree of restriction as compared to dermoid cysts.…”