Mast cell-associated Renaut bodies in the peroneal nerve of a dog with a history of mastocytosis

Multiple Renaut bodies were identified by light microscopy in the biopsied common peroneal nerve of a dog with generalized neuropathy, hypothyroidism and a history of cutaneous mastocytosis. In addition, numerous granulated c ells were associated with most of the Renaut bodies. Electron microscopic e xamination confirmed these to be mast cells, both central and peripheral to Renaut bodies, a phenomenon never previously reported. Endoneurial fibrosi s, myelinated fiber loss, as well as evidence of axonal degeneration, demye lination and remyelination were observed. 'Vacuolation' of endoneurial fibr oblasts was also present. The location of these Renaut bodies in the common peroneal nerve, and the absence of any documented or expected nerve compre ssion, implicates other etiological factors. These observations are the fir st to report an association between mast cells and Renaut bodies. It is pos sible that mast cells, at least in this case, are involved in the formation of Renaut bodies.