We report a case of a large, ulcerating proliferating trichilemmal cyst in a 63-year-old woman, with clinical, radiological, macroscopic, and microscopic correlation. The outbreak of the Coronavirus pandemic delayed her treatment. We review the literature on proliferating trichilemmal cysts, which are relatively rare tumors, which generally are considered benign. However, we found a high rate of malign cases, which stresses the importance of rapid surgical excision and histological diagnosis. Even though our proband had delayed treatment, the tumor did not transform to a malignant form.
 Introduction 
Proliferating trichilemmal cysts (PTCs) are relatively rare tumors that may appear all over the body but most frequently on the scalp in middle-aged women (1). PTCs occur in a benign and malignant form, but the differentiation between malignant PTC and benign PTC has been debated, implying that all PPT should be treated with the expectation that it could transform into a malignant tumor (2). There are no absolute clinical criteria that can differentiate between benign and malign PTC, why surgery is necessary to give a correct histopathological diagnose. The malignant form may metastasize (3).