Pathologic fracture: a rare initial manifestation of sarcoidosis.

Sarcoidosis is a multisystem granulomatous disease that most commonly involves the lungs and intrathoracic lymph nodes. Osseous involvement is uncommon, reported in approximately 1%-14% of cases, and is frequently subclinical or discovered incidentally on imaging. Symptomatic bone involvement as the presenting manifestation of sarcoidosis is rare. In the largest single-center series, only 1 of 20 patients (5%) had osseous disease as the sole manifestation. We describe a 48-year-old man who presented with progressive atraumatic right shoulder pain and was initially suspected to have rotator cuff pathology. MRI instead revealed supraspinatus and infraspinatus tendinitis, multifocal destructive osseous lesions involving the humerus and scapula, and a pathologic scapular fracture. Subsequent FDG PET-CT demonstrated pulmonary and multifocal skeletal hypermetabolic lesions, and CT-guided biopsy of the left iliac crest showed non-caseating granulomas, establishing the diagnosis of sarcoidosis. This case highlights the diagnostic challenge of osseous sarcoidosis when it presents before a known systemic diagnosis and mimics both common shoulder pathology and metastatic disease. It also illustrates the value of advanced imaging and tissue diagnosis in clarifying destructive bone lesions in patients without classic systemic symptoms.