Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder that results from genetic defects in DNA repair and manifests with a marked hypersensivity to ultraviolet rays. Children with X-P are at high risk of developing skin cancers. On the other hand, hypercalcemia-hyperleukocytosis is a rare paraneoplastic syndrome in children with cancer compared to adults. Here, we report a five-year-old female with X-P and squamous cell carcinoma (SCC). The patient presented with a necrotic, ulcerating huge mass sized 20x15x10 cm involving the right half of the face. She had a history of increased freckling over the face since the age of two years. Her other cutaneous findings are dryness of skin, photosensitivity, freckling and telengiectasis all over the body. A diagnosis of Xeroderma pigmentosum was made based on clinical features. She also had high fever, anemia, hyperleukocytosis, thrombocytosis and hypercalcemia. After pathological diagnosis of squamous cell carcinoma, she was treated with chemotherapy. All the symptoms and signs resolved dramatically with the initiation of chemotherapy. Our case is an example of early development of massive disfiguring SCC in children with undiagnosed and untreated X-P. Although we could not prove the paraneoplastic nature of hypercalcemia-hyperleukocytosis, dramatic response to the chemotherapy may be an evidence for paraneoplastic origin.

Keywords: hypercalcemia, hyperleukocytosis, paraneoplastic syndrome, squamous cell carcinoma, xeroderma pigmentosum