Milwaukee Shoulder Syndrome (MSS) is a painful progressive
arthropathy in which
hydroxyapatite crystal deposition in synovial tissue induces lysosomal release of
collagenase and neutral
proteases. These
enzymes are destructive to periarticular tissue, including the synovium, articular cartilage, rotator cuff muscles, and the intrasynovial cortical bone. MSS predominantly occurring in women (90%) over the age of 70 years of age with a clinical history marked by recurrent joint effusions and
pain, which classically worsens at night. Our patient is a 69-year-old woman who presented with progressive
shoulder pain, most prominent at night, with limited range of motion and swelling; intermittent discharge; and intermittent
neck pain that radiated to her right upper extremity. Her medical history was notable for invasive
carcinoma of the right breast treated with
mastectomy and radiation. She was also treated with
radiation therapy for right
shoulder pain and a lucent right shoulder lesion presumed to be metastatic
breast cancer. The remainder of her medical history consists of
hypertension,
diabetes mellitus,
hyperlipidemia, and uneventful bilateral total knee
arthroplasties. At presentation, she denied constitutional symptoms. Based on the patient's history and physical exam the differential diagnosis included primary and metastatic
malignancy, radiation induced
sarcoma and
necrosis,
infection,
Charcot disease, and
crystal arthropathies. Physical exam, laboratory findings, and imaging studies led us to the diagnosis of MSS.