Objective. Because musculoskeletal ultrasound (MSUS) is highly user dependent, we aimed to establish whether non-mentored learning of MSUS is sufficient to achieve the same level of diagnostic accuracy and scanning reliability as has been achieved by rheumatologists recognized as international experts in MSUS. Methods. A group of 8 rheumatologists with more experience in MSUS and 8 rheumatologists with less experience in MSUS participated in an MSUS exercise to assess patients with musculoskeletal abnormalities commonly seen in a rheumatology practice. Patients' established diagnoses were obtained from chart review (gout, osteoarthritis, rotator cuff syndrome, rheumatoid arthritis, and seronegative arthritis). Two examining groups were formed, each composed of 4 less experienced and 4 more experienced examiners. Each group scanned 1 predefined body region (hand, wrist, elbow, shoulder, knee, or ankle) in each of 8 patients, blinded to medical history and physical examination. Structural abnormalities were noted with dichotomous answers, and an open-ended answer was used for the final diagnosis. Results. Less experienced and more experienced examiners achieved the same diagnostic accuracy (US-established diagnosis versus chart review diagnosis). The interrater reliability for tissue pathology was slightly higher for more experienced versus less experienced examiners ( ‫؍‬ 0.43 versus ‫؍‬ 0.34; P ‫؍‬ 0.001). Conclusion. Non-mentored training in MSUS can lead to the achievement of diagnostic accuracy in MSUS comparable to that achieved by highly experienced international experts. Reliability may increase slightly with additional experience. Further study is needed to determine the minimal training requirement to achieve proficiency in MSUS.

Background: Prostate sarcoma is a rare group of prostate primary malignant tumors with a poor prognosis, and its early diagnosis is challenging. Here we report a case of early diagnosis of prostate sarcoma and summarize the clinical characteristics of this group of patients. Case presentation: We present a case of a 40-year-old male patient with prostate leiomyosarcoma having hematospermia as the initial symptom. His prostate-specific antigen was 2.97 ng/ml, magnetic resonance imaging showed a prostate nodule with possible bleeding at the lesion margins with Prostate Imaging Reporting and Data System (PI-RADS) category 2. According to the guidelines, prostate biopsy was not recommended, but we learned from our previous experience and still recommended him for prostate biopsy. With his consent, a combined prostate biopsy was performed, and he received an early diagnosis of prostate leiomyosarcoma 19 days after the initial symptom of hematospermia. Reviewing previous cases of prostate sarcoma patients at our medical center, we found that the best time for diagnosis and treatment were generally missed. Conclusions: Combination with magnetic resonance imaging is contributive to the early diagnoses of prostate sarcoma. Therefore, when young patients present with repeated hematospermia, even if they have normal prostate-specific antigen, it is important to be alert to the possibility of prostate sarcoma, and multiparametric magnetic resonance imaging rather than ultrasound is recommended, and if MRI reveals prostate lesions, it is recommended to be biopsied regardless of PI-RADS categories, and a combined biopsy is recommended.