Àt the time of the MRI, the patient's findings were considered to be most consistent with a viral myositis or Guillain-Barré syndrome, reported Kristina P. Callis, M.D., a dermatology resident at the University of Utah Health System in Salt Lake City.
In addition, a painful nodule in his left thigh with overlying erythema was diagnosed as thrombophlebitis. He was referred to dermatology 4 months later with scrotal ulcers and follicular papules and pustules elsewhere on his skin.
The scrotal ulcers and varied skin lesions developed 6 weeks after the onset of myositis. A skin biopsy from a scrotal ulcer showed the destruction of venule-like vascular structures and an interstitial inflammatory response of neutrophils; a muscle biopsy from the calf showed scattered atrophic muscle fibers and foci of perivascular infiltrate of chronic inflammatory cells consistent with an active myopathy.
The differential diagnosis initially included Behçet's syndrome, syphilis, Crohn's disease, pyoderma gangrenosum, other vasculitides, or other infections, Dr. Callis said.
The patient had no gastrointestinal, CNS, visual, or urinary symptoms. He had minimal joint symptoms (knee arthralgias), and—although he initially denied oral ulceration—the appearance of an oral ulcer clinched the diagnosis of Behçet's syndrome.
The International Study Group criteria for Behçet's syndrome requires recurrent oral ulceration at least three times per year, plus any two of the following: recurrent genital ulceration; eye lesions (uveitis, cells in the vitreous, or retinal vasculitis); cutaneous lesions (erythema multiforme, papulopustular lesions, pseudofolliculitis, or acneiform nodules); or a pathergy test interpreted at 24-48 hours.
Myositis is a rare presentation of Behçet's syndrome, having been reported only 11 times in the English literature, according to Dr. Callis.
The patient was started on 60 mg of prednisone daily, with both the scrotal ulcers and myositis resolving. However, because of the long-term side effects of prednisone, other therapies including colchicine were under consideration at the time of the case report.
A biopsy of the calf muscle showed atrophic fibers and inflammatory cells consistent with myopathy.
Criteria for Behçet's syndrome requires recurrent oral ulceration at least three times per year. Photos courtesy Dr. Kristina P. Callis