Spindle cell and sclerosing rhabdomyosarcoma (ssRMS) is a rare variant of rhabdomyosarcoma, which includes three distinct subtypes. In infants, these tumors are commonly associated with recurring fusions involving VGLL2 or NCOA2 and have a favorable prognosis. We present four cases of ssRMS and 16 additional cases from the literature, which show that these patients present with localized disease and have an excellent prognosis regardless of surgical margin or lack of radiation therapy. Molecularly defined spindle cell rhabdomyosarcoma in infants is likely a biologically distinct entity which may not require the aggressive multimodal treatment used for other subtypes of rhabdomyosarcoma. K E Y W O R D Scongenital, NCOA2, pediatric, rhabdomyosarcoma, VGLL2

This is the first reported occurrence of nephrotic-range proteinuria in a child treated with ATRA. Nephrologists should be aware that RAS is a serious complication of ATRA that may lead to proteinuria.

Giant cell tumor of the bone (GCTB) is an uncommon bone tumor, usually localized, and rarely presents at <20 years of age. Denosumab, a fully human monoclonal antibody against RANKL (receptor activator of nuclear factor κB ligand), is approved for the treatment of unresectable GCTB in skeletally mature individuals. We present a case series of 2 pediatric patients with recurrent GCTB with pulmonary metastasis, with clinical response to denosumab therapy.

These results were presented in abstract form by Ankhi Dutta ("Epidemiology, management and outcome of invasive mold infections in pediatric hematological malignancies at a tertiary care center: a 10 year review," IDWeek annual meeting, 2016), and by Ashley Ikwuezunma ("Antifungal prophylaxis and risk for invasive mold infections in children with hematologic malignancies," American Society of Hematology annual meeting, 2020).