Abstract
Background/Objectives: Paget–Schrotter syndrome (PSS), or primary axillary-subclavian vein thrombosis, is an uncommon but clinically important form of upper extremity deep vein thrombosis. It often affects young, physically active patients and may initially be interpreted as a musculoskeletal disorder. This scoping review, combined with a contemporary primary care case, aimed to map the reported clinical presentation, diagnostic delay, and initial misdiagnosis of classic PSS. Methods: The review was conducted using the Arksey and O’Malley framework and reported in accordance with the PRISMA extension for scoping reviews (PRISMA-ScR). PubMed was searched for English-language publications from 1 January 2000 to 1 March 2026. Eligible reports described effort-induced thrombosis involving the axillary and/or subclavian venous segment. Secondary upper extremity deep vein thrombosis, non-effort thrombosis, pseudo-PSS, isolated distal venous thrombosis, and reports without extractable patient-level presentation data were excluded. Data were charted descriptively. Results: Among 1954 screened records, 143 studies met inclusion criteria and contributed 165 published patients. Together with the present case, the synthesis included 166 patients. Median age was 28 years, and 73.5% were male. Arm swelling (95.2%), pain (80.1%), cyanosis or discoloration (69.9%), and venous distension (70.5%) were the most frequent presenting features. Diagnostic delay was reported in 27.3% of patients with reported data, whereas initial misdiagnosis was reported in 21.7% of included patients. Musculoskeletal injury or muscle strain was the most common initial misdiagnosis, accounting for 66.7% of misdiagnosed cases. Pulmonary embolism was reported in 24.7% of patients, although this reported frequency is likely influenced by case-report publication bias, selective imaging, and preferential reporting of more severe presentations, and should not be interpreted as a population-level risk estimate. Conclusions: PSS should be considered in young or otherwise low-risk patients with unilateral arm swelling after strenuous or repetitive upper extremity activity. Greater awareness of this clinical presentation in primary care and general emergency settings may reduce diagnostic delay and post-thrombotic morbidity.