A large and late mediastinal metastasis from a uterine smooth muscle tumour of uncertain malignant potential: A case report

INTRODUCTION: Smooth muscle tumours of uncertain malignant potential (STUMP) are mesenchymal uterine tumours with a malignant potential found somewhere between that of benign leiomyomas and leiomyosarcomas. Only three cases of STUMP pulmonary metastasis exist in the literature. CASE PRESENTATION: We report the case of a 63 year-old female patient presenting with dysphonia secondary to recurrent laryngeal nerve paralysis due to an enormous mediastinal STUMP metastasis, 14 years after having undergone a total hysterectomy with bilateral salpingo-oophorectomy. A successful left pneumonectomy was performed and the mass weighing 1570 g was histologically confirmed as a STUMP metastasis. DISCUSSION: Only three cases of pulmonary metastasis from STUMP have been reported in the recent literature and no robust information exists about the metastatic nature of STUMP. No cases exist in the literature of a successful pneumonectomy performed for a STUMP metastasis of such large dimensions presenting after many years from the diagnosis of the primary uterine lesion. Physicians should keep in mind that the finding of a smooth muscle tumour in the lung of a woman should promptly raise the suspicion of a metastatic uterine malignancy, even several years after diagnosis of the primary lesion. CONCLUSION: Despite the size, invasiveness and late presentation of the STUMP metastasis, the surgery was successful and the patient no longer requires oxygen therapy.