EC Clinical and Medical Case Reports

Catastrophic antiphospholipid syndrome (CAPS) is a rare and life-threatening thrombotic disorder characterized by diffuse microvascular thrombosis leading to multiorgan failure. Musculoskeletal involvement is exceedingly rare, with only isolated cases of muscle infarction reported in the literature. We report the case of a 44-year-old man with CAPS involving the heart, kidneys, and liver who developed acute bilateral lower-limb pain, swelling, and functional impairment. Multimodality imaging revealed extensive lower-limb myonecrosis and played a pivotal role in establishing the diagnosis while excluding the main differential diagnoses. This case highlights the crucial role of imaging, particularly MRI, in the diagnosis of ischemic myonecrosis complicating CAPS, especially as muscle biopsy, although considered the reference standard, is invasive and associated with infectious complications that limit its use. It also expands the spectrum of musculoskeletal manifestations of this disease.

Keywords: Catastrophic Antiphospholipid Syndrome; Antiphospholipid Syndrome; Myonecrosis; Muscle Infarction; Magnetic Resonance Imaging; Computed Tomography, Stipple Sign

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