Isolated uterine metastasis from a lung adenocarcinoma

A 65-year-old woman was referred with an incidental finding of a flurodeoxyglucose-avid uterine lesion, following excision of a local lung adenocarcinoma. MRI had features concerning for an atypical fibroid or smooth muscle tumour of uncertain malignant potential. She underwent a total abdominal hysterectomy and bilateral salpingo-oophorectomy. Histopathology demonstrated a leiomyoma infiltrated with adenocarcinoma consistent with a secondary lesion from the lung cancer. Among the small number of cases of uterine metastases of extra-pelvic primary cancers reported in the literature, those from lung cancers are very rare. Concerning features for an atypical fibroid included the patient's age and postmenopausal status, as well as positron emission tomography and MRI findings. A metastatic secondary cancer was not suspected. Diagnosis was only made after histopathological examination. This case represents a very unusual cause of a uterine mass. It demonstrates the importance of thorough preoperative work-up and accurate histopathological assessment.