Rothmund-Thomson syndrome (RTS), also known as poikiloderma congenitale, is a rare genetic disorder characterized by its pleiotropic nature, affecting multiple organ systems. Key features of RTS include early photosensitivity and facial erythema that progresses to poikiloderma, as well as sparse scalp hair, absent or sparse eyebrows and eyelashes, juvenile cataracts, short stature, and skeletal abnormalities. Patients with RTSII, often attributed to mutations in the RECQL4 helicase gene, are predisposed to osteosarcoma and skin cancer. Herein, we present a case study of an eight-year-old female with heterogeneous mutations in RECQL4. The patient exhibited an exfoliative erythematous rash on face and diaper area at the age of 7- months, along with absent eyelashes and scanty eyebrows. Subsequently, she developed osteosarcoma, and she is currently undergoing treatment.