Childhood Eyelid Pilomatricoma Mimicking Recurrent Chalazion

Pilomatricoma is a rare benign subcutaneous childhood tumor first described in 1880. It has no gender predilection. The exact etiology of this disease is still unknown. However, association with mutation in the CTNNB1 gene was reported. The most frequent location is the neck, although the upper eyelid is an uncommon site of involvement. The diagnosis of pilomatricoma is clinically challenging, and is based on histopathologic examination, after complete surgical excision, which is the radical treatment. It shows foreign body reaction that surrounds nucleated basophilic cells and islands of enucleated calcified ghost cells. The tumor may have diverse clinical presentations and aspects. It commonly manifests as an asymptomatic, solitary subcutaneous mass. Some clinical signs are specific such as the tend sign and the teeter-totter sign. Squamous and basal cell carcinoma are the main clinical differential diagnoses, and should be routinely ruled out. Radiologic investigations (ultrasonography and Magnetic resonance imaging: MRI) may enhance diagnosis accuracy in atypical cases. Ultrasonography shows hyperechoic and heterogeneous mass. MRI is more specific for diagnosis showing homogeneous well-defined mass on T1-weighted scans and high signal intensity on T2-weighted images. Pilomatricoma of the upper eyelid may be misdiagnosed and treated as recurrent chalazion. Recurrence and malignant transformation of pilomatricoma are rare after complete surgical excision. This case report is about a 14-year-old healthy boy who exhibited large pilomatricoma in the upper eyelid initially misdiagnosed and mistreated as chalazion.