Update on cancer screening in children with syndromes of bone lesions, hereditary leiomyoma and renal cell carcinoma syndrome, and other rare syndromes.

The management of children with syndromes associated with an increased risk of benign and malignant neoplasms is a complex challenge for healthcare professionals. The 2023 AACR Childhood Cancer Predisposition Workshop provided updated consensus guidelines on cancer surveillance in these syndromes, aiming to improve early detection, intervention, and reduce morbidity associated with such neoplasms. In this paper, we review several of the rare conditions discussed in this workshop. Ollier disease and Maffucci syndrome are enchondromatoses (disorders featuring benign bone lesions) with up to 50% risk of malignancy, including chondrosarcoma. These patients require surveillance with baseline whole-body MRI and routine monitoring of potential malignant transformation of bony lesions. Hereditary Multiple Osteochondromas carry a lower risk of chondrosarcoma (<6%) but still require lifelong surveillance and baseline imaging. Related syndromes of benign bone lesions are also described. Hereditary leiomyomatosis and renal cell cancer syndrome (HLRCC), associated with fumarate hydratase pathogenic variants, is discussed in detail. Surveillance for RCC in pediatric age is recommended, as well as prompt intervention when a lesion is detected. Schinzel-Giedion Syndrome and Rubinstein-Taybi Syndrome are described for their associated malignancies and other complications, as well as expert consensus on the need for childhood cancer surveillance. Clinical recommendations, including imaging modalities and frequency of screenings, were proposed and are tailored to each syndrome's age-specific tumor risk profile. In all syndromes, patients and their families should be educated about the potential malignancy risk and advised to seek medical care for rapid growth of a mass, persistent pain, or other unexplained symptoms.