Malignant change in an intradiploic epidermoid cyst

Area of Science:

• Neurosurgery
• Oncology
• Pathology

Background:

• Epidermoid cysts are benign congenital tumors, typically slow-growing and asymptomatic.
• Intra-diploic epidermoid cysts are rare, occurring within the diploë of cranial bones.
• Malignant transformation of epidermoid cysts is exceptionally uncommon.

Observation:

• A 43-year-old man presented with an intra-diploic epidermoid cyst of the parietal and occipital bones.
• The cyst remained quiescent for 12 years before exhibiting spontaneous malignant changes.
• Malignant transformation led to intra-cerebral involvement and tumor recurrence.

Findings:

• The case represents the first documented instance of spontaneous malignant transformation in an epidermoid cyst without prior surgical intervention.
• Aggressive tumor behavior and intracranial extension were observed post-transformation.
• Despite aggressive treatment including surgery, radiation, and chemotherapy, a fatal outcome occurred within one year due to recurrence.

Implications:

• This case underscores the potential for rare, aggressive behavior in seemingly benign intra-diploic epidermoid cysts.
• It emphasizes the need for vigilance and potentially long-term monitoring of these lesions, even when asymptomatic.
• Further research into the mechanisms of malignant transformation in epidermoid cysts may inform future treatment strategies.