Tumours involving the brachial plexus in seven dogs.

Seven cases with tumours localised in the brachial plexus are described. The main clinical features were a progressive lameness in one forelimb with marked muscle atrophy and very obvious but non-localizable pain. A palpable lump in the axilla was present in less than half the cases. Ancillary aids contributed little in the diagnosis except for electrophysiology which gave evidence of neural damage at an early stage of the disease and as such may be the most useful aid to an early diagnosis. Two different pathological entities were observed, the first where the tumour, primarily of neural origin (usually a neurofibrosarcoma), arose within the nerves themselves and the second where the tumours arose in adjacent tissue and involved the plexus by local infiltration. In all cases the prognosis was hopeless because of local infiltration of the tumour and metastases. In the early stages accurate diagnosis can be difficult in the absence of a mass but the possibility should be considered in any case where chronic lameness with obvious non-localizable pain is present in one forelimb.