MORPHOLOGICAL AND CLINICAL ASPECTS OF HETEROTOPIC OSSIFICATION IN SPORTS - A CASE-STUDY

Heterotopic ossification (HO) caused through sport injuries is a rare, clearly defined lesion. In a considerable number of cases, however, n o adequate trauma can be remembered or otherwise established in the '' sporting history''. Differential diagnosis of this non-traumatic HO va riant often presents many problems which may lead to the wrong diagnos is of sarcoma. We looked at 28 cases, in which in more than 50 % a sar coma was discussed as primary diagnosis. These difficulties arise main ly in cases where clinical features suggest a tumor, radiological chan ges are unspecific, and the diagnosis is based on a small biopsy sampl e. We demonstrate and discuss the problems involved in differential di agnosis using the history of a matchgrade sportsman as a sample. Unlik e in sarcoma, patients with HO usually suffer severe pain, and well ov er 50 % of all patients develop the disease during the 2nd or 3rd deca de. Over 90 % of all patients with soft tissue sarcoma, however, are o ver the age of 30. From the morphological point of view, the different histological pattern of HO has to be taken into account, since early stages may mimick a sarcomatous lesion. If the clinical findings sugge st the presence of HO, surgical intervention including the taking of b iopsy sample should be postponed, so that instead of early highly mito tic active phases more mature bone structures, which are easier to cla ssify, will be available for evaluation. Only a profound knowledge of the different phases of HO, together with clinical and radiological fe atures, will clarify the differential diagnostic problems of the non-t raumatic variant of this lesion in sportsmen.