Muscular polyarteritis nodosa as a cause of fever of undetermined origin: a case report and review of the literature.

We describe an unusual presentation of a localized form of polyarteritis nodosa (PAN) manifested by fever of undetermined origin (FUO). Biopsies of the gastrocnemius muscle revealed necrotizing arteritis and initiation of prednisolone (PSL) brought rapid response. The PAN localized to muscle is rare; furthermore, this disease presented as FUO is very rare.