Rare primary malignant mixed Müllerian tumor of the mediastinum: A case report

RATIONALE: Malignant mixed Müllerian tumor (MMMT) of extragenital organs is rare, especially in male. To our knowledge, this is the first reported case of primary MMMT at the mediastinum in male. PATIENT CONCERNS: A 54-year-old male was admitted to the hospital due to repeated stimulating dry cough for 2 years. His systemic examination was unremarkable. Laboratory workup revealed that all blood indicators were within normal limits. But subsequent computerized tomography (CT) scans of chest showed an abnormal soft tissue density in the area of its left, measuring approximately 4 cm in anterior-posterior dimension and 7 cm in maximum transverse dimension. DIAGNOSES AND INTERVENTIONS: The pathogenesis of these tumors remains controversial. The diagnosis is combined with biopsy and immunohistochemical staining. So, the patient underwent radical surgical resection and pathologic examination of the excised specimen was consistent with the diagnosis of MMMT. After surgery, he was treated by sequential chemoradiotherapy. OUTCOMES: The patient died from tumor recurrence 16 months later. LESSONS: MMMT is a rare, highly aggressive tumor associated with interesting embryological origin, a definite diagnosis of which is only confirmed on pathological assessment. Due to its high degree of malignancy and high rate of recurrence, complete macroscopic excision of the tumor is recommended as soon as possible.