An inflammatory myofibroblastic tumour presenting with limited mouth-opening, hypoesthaesia of the left chin and infraorbital area, intermittent left eye ptosis and converging strabismus

Abstract

An inflammatory myofibroblastic tumour (IMT) is a rare neoplasm of mesenchymal origin, defined by myofibroblastic spindle cells accompanied by inflammatory cells, lymphocytes and eosinophils. Its symptomatology depends on the involved site and tends to mimic a malignant tumour clinically and radiologically. The head and neck region accounts for 5% of all IMTs. Here, we report a case of a 35-year-old woman, with no medical history, who presented with a mouth-opening limitation of 8 mm evolving for three years and occurring six months after of a wisdom tooth extraction. She also experienced a recent occurrence of left eye ptosis and a converging strabismus. On examination, the patient had a body temperature at 37°C, with hypoesthaesia of the left chin and infraorbital area, without any other abnormality. Laboratory examinations did not reveal a biological inflammatory syndrome or rhabdomyolysis. The infectious investigations were all negative, as well as the immunological tests, in particular negative for anti-AChR and anti-MuSK antibodies. On the facial computed tomography (CT) scan, we noted an active reshuffle in the left mandible ascending branch with a thickening of the ipsilateral pterygoid muscles and the left temporal meningeal tissue. After corticosteroid therapy 0.7 mg/kg/j, we obtained an improvement in the patient’s mouth-opening, thus a biopsy of the lesion was performed under local anaesthesia, revealing IMT. The patient continued the corticosteroids therapy with a progressive tapering resulting in a marked clinical improvement of the mouth-opening limitation and her ptosis.