Rare Case of Langerhans-Cell Histiocytosis in Pediatric Patient with Lynch Syndrome Highlighted by Researchers

Strategic Insights -

A unique case of Langerhans-cell histiocytosis (LCH) in a pediatric patient with Lynch syndrome has been reported by researchers at Memorial Sloan-Kettering Cancer Center. The study, published in the JBJS Case Connector, details the treatment and outcome of a 12-year-old boy who developed osteosarcoma and LCH after chemotherapy and pembrolizumab. The case underscores the importance of advanced testing in patients with osteosarcoma and poor response to chemotherapy, and of tissue sampling when patients with a primary malignancy develop new bone lesions.

Key Takeaways:

  • The patient, a 12-year-old boy, was diagnosed with Lynch syndrome, a genetic disorder associated with an increased risk of various cancers, including osteosarcoma and LCH.
  • The patient developed osteosarcoma of the left femur after chemotherapy and pembrolizumab, and two years later, an aggressive lesion in the contralateral femur was thought to be metastatic osteosarcoma but was later revealed to be LCH.
  • The treatment included cytotoxic chemotherapy, wide resection, and pembrolizumab.
  • The case highlights the importance of advanced testing in patients with osteosarcoma and poor response to chemotherapy, and of tissue sampling when patients with a primary malignancy develop new bone lesions.
  • Osteosarcoma and LCH are rare and aggressive bone cancers that can occur in children and adults.
  • Lynch syndrome is a genetic disorder that increases the risk of various cancers, including osteosarcoma and LCH.
  • Pembrolizumab, a cancer immunotherapy, was used in the treatment of the patient.

Statistics:

  • The patient was 12 years old when diagnosed with osteosarcoma.
  • The patient took two years to develop a new bone lesion that was thought to be metastatic osteosarcoma but was later revealed to be LCH.
  • The treatment included 4-6 cycles of cytotoxic chemotherapy, wide resection, and pembrolizumab.
  • Langerhans-cell histiocytosis occurs in approximately 1 in 200,000 children per year.
  • Lynch syndrome is responsible for approximately 3% of all colorectal cancer cases in the United States.
  • Osteosarcoma is the most common type of cancer found in bones, accounting for approximately 15% of all bone cancer cases in the United States.

Sources:

  • Osteosarcoma and Langerhans Cell Histiocytosis in a Pediatric Patient with Lynch Syndrome: A Case Report. JBJS Case Connector, 2024;14(4).
  • NewsRx. Findings on Langerhans-Cell Histiocytosis Reported by Researchers at Memorial Sloan-Kettering Cancer Center (Osteosarcoma and Langerhans Cell Histiocytosis in a Pediatric Patient with Lynch Syndrome: A Case Report). Respiratory Therapeutics Week. October 13, 2025; p 217.