Peculiar Phenotype of Linear Prepubertal Hidradenitis Suppurativa Associated With Trisomy 13: Report of Two Clinical Cases

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease that typically affects intertriginous areas and is rarely associated with chromosomal abnormalities. This report describes two pediatric cases of HS‐like lesions overlying phylloid pigmentary mosaicism, both associated with mosaic trisomy 13. The first case involves a 5‐year‐old girl with developmental anomalies and comedonal lesions localized to areas of pigmentary mosaicism, confirmed by skin biopsy showing 30% aneuploid cells with full trisomy 13. The second case is a 15‐month‐old girl who developed follicular lesions years later overlying a hypopigmented mosaic patch; genetic analysis of skin tissue revealed 50% aneuploid cells with partial trisomy 13. These cases support an emerging link between mosaic trisomy 13 and follicular occlusion disorders, including HS. The involvement of chromosome 13 genes, such as GJB2 (connexin 26), may play a role in the pathogenesis.