An unusual location of a benign glomus tumour, outside of the constantly located regions, e.g. in the subungual location or deeply sited in extremities, was diagnosed in a 56-year-old white female in her posterior upper mediastinum. The single similar case report was published before the era of electron microscopy and immunohistochemistry and single cases of atypical and malignant forms in this unusual location were published only recently. The tumour measuring 5 x 4 x 2 centimeters has caused cough and was associated with occasional righ-sided chest pain. Its rich vascular supply has caused intensive intraoperative bleeding. The postoperative course was une- ventful and the patient is free of neoplastic disease or symptoms six years after surgery. Nume- rous mast cells present within the tumour’s interstices must be considered in relation to the possible pathogenesis of the up to now unexplained pain in glomus tumours.

        Key words: Benign glomus tumour - Upper mediastinum - Immunohistochemistry - Electron mic- roscopy