Langerhans Cell Histiocytosis in a Patient with Lynch Syndrome (Hereditary Non Polyposis Colorectal Cancer)

A fifty three year old white female smoker with Lynch Syndrome was receiving adjuvant chemotherapy for node positive caecal adenocarcinoma. Interval investigations demonstrated a second primary gastric cancer with bilateral pulmonary nodules of indeterminate significance. Lung biopsy revealed Langerhans cell histiocytosis (LCH). Our case highlights the importance of non-malignant pathology mimicking malignancy in a patient at risk of multiple primary tumors. To our knowledge an association between Lynch syndrome and LCH has not been previously documented, we review the literature.