thoracotomy: surgical incision into the chest walls opening up the pleural cavity
incision: the cutting of or into body tissues or organs (especially by a surgeon as part of an operation)
xeroderma pigmentosum: a rare genetic condition characterized by an eruption of exposed skin occurring in childhood and photosensitivity with severe sunburn; inherited as a recessive autosomal trait in which DNA repair processes are defective so they are more likely to chromosome breaks and cancers when exposed to ultraviolet light