Multifocal chondromesenchymal hamartoma of the chest wall in a 4-month-old infant: a case report and review of the literature.

Chondromesenchymal hamartoma of the chest wall (CMHCW) is an extremely rare benign tumour-like lesion typically presenting in early infancy, arising from one or more ribs and capable of mimicking malignancy. We report a 4-month-old male infant who presented with an incidentally discovered firm left posterolateral chest wall mass. Contrast-enhanced computed tomography revealed a large heterogeneously enhancing mass centred on the left sixth rib with rib destruction and partial involvement of adjacent ribs, alongside two smaller ipsilateral anterior chest wall lesions-confirming a multifocal unilateral presentation. Percutaneous ultrasound-guided Tru-cut biopsy and subsequent incisional biopsy of all lesions confirmed CMHCW histopathologically. Following multidisciplinary team discussion, staged surgical resection with mesh reconstruction was performed for all lesions, with postoperative histopathology confirming complete excision. The patient remains on regular clinical and radiological follow-up. This case highlights the importance of multidisciplinary evaluation, pre-operative biopsy, and staged surgical resection in multifocal CMHCW.