Abstract

Pilomatrixoma, also known as calcifying epithelioma of Malberbe, is a rare, benign skin tumor derived from hair follicle matrix cells. It predominantly affects young children but can occur across all age groups, with a slight female preponderance. This study presents the case of a 7-year-old female with a gradually enlarging mass on the left arm, diagnosed as pilomatrixoma following surgical excision and histopathological analysis. Pilomatrixoma typically manifests as a solitary, firm, skin-colored or purplish lesion, most commonly on the head, neck, or upper extremities. It is characterized by calcification within the lesion, often presenting the “tent sign,” and is generally asymptomatic but can occasionally cause tenderness. Dermoscopy, imaging (e.g., ultrasound, X-ray), and biopsy are critical diagnostic tools, with histological findings revealing basophilic cells, shadow cells, and calcium deposits. The lesion in this case was excised surgically, a treatment that remains the standard to confirm diagnosis, alleviate cosmetic concerns, and prevent rare complications like malignant transformation. Although rare, pilomatrixoma may recur or become pilomatrix carcinoma. This research underscores the importance of early diagnosis and treatment of pilomatrixoma for favorable outcomes.