Heterotopic ossification of peripheral nerve (" XXXX ossificans"): report of two cases.

@entity1 @entity1183 @entity79 @entity5323 @entity158 @entity2736 @entity130 @entity5013
OBJECTIVE AND IMPORTANCE: @entity2736 (" @entity5013 ossificans") is among the least frequently encountered reactive lesions in peripheral nerves. Only two cases have been described previously, one in the median nerve of a 34-year-old @entity1 , and the other in the ulnar nerve of an adult @entity1 . The architecture of this lesion is distinctly zonal. Consisting of a central fibroblastic core, an intervening zone of osteoid production, and a peripheral layer of ossification, the pattern is remarkably similar to that of @entity5323 . This similarity and the occurrence of the process in superficial nerves have led to speculation that @entity130 plays a role in its pathogenesis; this hypothesis remains unproved. We describe two additional cases of @entity5013 ossificans. CLINICAL PRESENTATION: One @entity1 , a 41-year-old @entity1 , experienced @entity158 and @entity1183 in the left leg for several months but had no history of local @entity130 . A mass was detected in the saphenous nerve. The second @entity1 , a 16-year-old @entity1 , noted subacute onset of @entity158 in the popliteal fossa and decreased sensation in the distribution of the lateral sural cutaneous nerve. A mass was found within the tibial nerve at the knee level. INTERVENTION: In each @entity1 , resection of the mass required sacrifice of a segment of the nerve. CONCLUSION: In each @entity1 , the mass was composed of fibrovascular tissue with @entity79 arranged in a zonal pattern. The ossifying process was intraneural but encased rather than directly involving nerve fascicles. These exceptionally intact examples of @entity5013 ossificans underscore its resemblance to @entity5323 . Nerve-sparing resection of such masses is not always possible.
