A 25 year old patient presented with an enlarging shoulder mass. CT and MRI exams were performed and the findings are presented.
A 25 years old patient with a recent history of an enlarging shoulder mass was referred to the Radiology Department by his GP. He was afebrile and no history of trauma in the region was referred. A clinical examination revealed a shoulder mass measuring 4 cm in diameter. CT scan and MRI were performed. On unenhanced CT there was a soft tissue mass at the region of deltoid muscle. The mass was slightly hypointense in comparison to the muscle. A central calcification was also present (fig 1). On T1 weighted image (fig 2) the mass was hyperintense compared to the muscular tissues. On T2 fat-suppressed – weighted image (fig 3, 4) the mass revealed a predominantly high MR signal with central area of low-signal intensity, representing calcification. After admission of contrast medium the tumor was strongly enhancing (fig 5). The patient underwent surgical excision of the tumor and the cytological examination revealed low grade leiomyosarcoma (fig 6).
Leiomyosarcoma (LMS) is a relatively uncommon malignant mesodermal neoplasm associated with smooth muscle differentiation, accounting for 5–10% of all soft-tissue tumors. They typically occur in adult life. Therefore, presence of LMS in young persons is associated with Epstein-Barr virus infection, especially in immunocompromised persons such as AIDS patients or after organ transplantation.
All leiomyosarcomas have the same histologic characteristics. However, they are divided into four different subgroups because of their clinical and biologic differences: (1) cutaneous, (2) major vessel LMS and (3) soft tissue LMS. Cutaneous lesions arise from pilar structures and, when restricted to the dermis, have an excellent prognosis with little or no risk of dissemination. Major vessel leiomyosarcomas (e.g.inferior vena cava) are extremely rare. Soft tissue leiomyosarcomas are divided in two groups because of the difference in prognosis: those arising in the retroperitoneum and body cavities and those arising in the peripheral or somatic soft tissues of the extremities.
Somatic soft tissue LMS develop in either superficial or deep soft tissues of the extremities, as in our case, where they originate from the smooth muscle of the wall of a small vessel. However, few of these tumors are associated with symptoms of vascular compromise. They are usually smaller than retroperitoneal lesions and metastasis are often. It does appear that leiomyosarcomas of somatic soft tissue have an unexpectedly aggressive course when they first detected and that feature may well relate to its angiocentricity.
Magnetic resonance imaging provides information on the origin and anatomic extent of musculoskeletal tumors. Leiomyosarcoma can have a relatively benign appearance on MR imaging with the only clinical clue to its malignant nature being a rapidly growing painful lesion.
Treatment of soft tissue leiomyosarcomas requires specialized multidisciplinary teams associating pathologists, radiologists, oncologists and surgeons. A combination of chemotherapy, surgery and radiotherapy usually make it possible to improve the management of this disease.
In our case, the location of the tumor was in the deep soft tissues of the right shoulder. The tumor originated from the smooth muscle of the wall of the small vessel and not from the striated muscle of deltoid. Imaging techniques revealed the location of the tumor and its relation with the subsequent tissues. The MRI finding suggesting its malignant nature was the strong enhancement of the tumor after admission of contrast medium. The definite diagnosis was based on the cytological examination where the origin of the tumor from a small vessel was illustrated.
Low grade leiomyosarcoma of the right shoulder
Based on the patient’s shoulder CT and MRI images, a round or near-round space-occupying lesion is observed in the deep soft tissues of the right shoulder:
Considering the patient’s young age, the shoulder soft tissue mass, and the radiological features, the following differential diagnoses can be considered:
Considering the radiological characteristics (a vascularized, markedly enhancing tumor in deep soft tissue) and pathological features (smooth muscle differentiation, nuclear atypia, and active proliferation), in conjunction with the patient’s age and clinical presentation (a rapidly enlarging painful mass), the most likely diagnosis is:
Leiomyosarcoma.
Confirmation primarily relies on histopathological examination and immunohistochemical results (e.g., positive for SMA, Desmin). If there remain any doubts, further pathological molecular testing or a biopsy should be performed to confirm the diagnosis.
For leiomyosarcoma, a multidisciplinary treatment strategy is often used, requiring collaboration among pathology, imaging, surgery, medical oncology, and radiotherapy. The main components include:
The postoperative or post-comprehensive treatment rehabilitation may be divided into the following phases:
Throughout the rehabilitation process, it is essential to follow the FITT-VP principle (Frequency, Intensity, Time, Type, Progression, and Individualization); adjust the plan based on the patient’s actual condition. If there is bone fragility, abnormal blood test results, or other complications, exercise intensity should be increased cautiously, and regular medical follow-up is advised.
This report provides a reference for medical analysis and cannot replace in-person consultation or professional medical advice. The specific diagnosis and treatment plan must be determined by a specialized medical team based on the patient’s actual condition.
Low grade leiomyosarcoma of the right shoulder
