Context:
Cutaneous epidermal cysts are common lesions, but fortunately, malignant transformation of their epithelium is rare. There are few case reports in the literature concerning malignant transformation of an epidermal cyst into squamous cell carcinoma. We present a case of squamous cell carcinoma arising from an epidermal inclusion cyst and describe the clinical and histopathologic findings.
Case report:
A tumour measuring 1.5cm was surgically excised. Based on the histopathologic findings of the tumour, this case was diagnosed as squamous cell carcinoma that arises in an epidermal cyst. Malignant change had not been suspected until histological examination revealed it. Nine months after tumour resection, the patient is free of disease.
Conclusion:
malignant transformation of an epidermal inclusion cyst is rare; this case illustrates the importance of routine histology in excision of epidermal cysts.