Presentation
For several months, soft, non-painful swelling of the scalp in the right occipital region.
Patient Data
In the subcutaneous tissue, above the galea capitis, there is a well-defined oval-shaped structure of approximately 1 cm, with a thin hyperechoic peripheral capsule and a heterogeneous center with some tiny calcifications.
Surgical removal
Histological report
Encapsulated well circumscribed simple cyst filled with cyst wall and solid, homogenous material, lined by stratified squamous epithelium that has a palisaded outer layer and contains dense laminated eosinophilic keratin with cholesterol clefts. Granular layer is absent. There are also calcification and giant cell reaction to the keratin. There's no cellular atypia. Finding consistent with trichilemmal cyst.
Case Discussion
Trichilemmal cysts are lesions originating in the isthmus of the hair follicle, and are formed by eosinophilic keratina. Common in women and occur in 90% on the scalp and sometimes on the extremities and scrotum wall.
Case courtesy Dr. Fabio Denicolò
Radiographer: TSRM Nunzio Bianco