Multicentric myofibroblastic sarcoma

SUMMARYWe report a case of synchronous, multicentric low-grademyofibroblastic sarcoma presenting in a 62-year-oldman. He initially presented with inflammatory symmetricpolyarthritis and adhesive capsulitis of his shoulder andhips bilaterally and did not respond to a trial of diseasemodifying antirheumatic drugs. Over a period of severalyears he developed progressive restriction of both kneesand nodules on his hands, both knees and back. Abiopsy of the nodule on his back was inconclusive andsubsequent biopsies on his left and then right kneerevealed a spindle cell neoplasm with an infiltrativegrowth pattern, mitotic figures, positive immunostainingfor smooth muscle actin and focal myxoid changeconsistent with myofibroblastic sarcoma. Whilemyofibroblastic sarcoma has been known to metastasise,to our knowledge, a multifocal presentation of thistumour has not been described previously.BACKGROUND This is a hitherto unreported presentation of myofi-broblastic sarcoma initially presenting with increas-ing stiffness and mimicking an inflammatoryarthritis. This tumour has been known to metasta-sise but a synchronous multifocal presentation hasnot been reported.