Pilomatricomal Horn With Confirmed CTNNB1 Mutation: A Rarely Reported Follicular Tumor

Area of Science:

• Dermatopathology
• Oncology
• Genetics

Background:

• Pilomatricoma is a common benign skin tumor originating from hair follicle matrix cells.
• CTNNB1 gene mutations are frequently observed in pilomatricomas, playing a key role in their pathogenesis.
• These tumors typically present as dermal or subcutaneous nodules.

Purpose of the Study:

• To describe a rare case of an epidermal-based pilomatricoma.
• To investigate the clinical presentation of this lesion, specifically its association with a cutaneous horn.
• To confirm the genetic basis of this variant through molecular analysis.

Main Methods:

• Clinical case presentation and histopathological examination.
• Next-generation sequencing for genetic mutation analysis.
• Literature review for similar reported cases.

Main Results:

• A rare pilomatricoma arising from the epidermis was identified.
• The lesion presented clinically as a cutaneous horn, a rare manifestation.
• Next-generation sequencing confirmed a CTNNB1 gene mutation in the tumor.
• This finding supports the relationship between this epidermal variant and conventional pilomatricoma.

Conclusions:

• Epidermal-based pilomatricoma is a rare variant of this common skin neoplasm.
• The presence of a cutaneous horn is a distinctive clinical feature.
• The identification of a CTNNB1 mutation reinforces the molecular link to pilomatricoma.