| disease | Smooth Osteosarcoma |
| alias | Leiomyosarcoma |
Smooth osteosarcoma is divided into three types based on the site of occurrence: ① cutaneous and subcutaneous type, ② retroperitoneal and mesenteric type, ③ vascular type.
bubble_chart Pathological Changes
1. Gross appearance: The tumor is round and nodular, with most tumors having clear boundaries and a firm texture. The cut surface is gray-white or gray-red, resembling fish flesh, and may be accompanied by hemorrhage and necrosis.
2. Microscopic appearance: The tumor cells are elongated spindle-shaped of varying sizes, with blunt round nuclei of unequal sizes and pink cytoplasm containing varying amounts of longitudinal myofibrils.
bubble_chart Clinical Manifestations
It is most common in individuals aged 40 to 60, occurring in the limbs, and generally has a prolonged course. Local excision is prone to recurrence, and it can metastasize hematogenously to the lungs, liver, and other organs, with a few cases metastasizing to regional lymph nodes. In children, soft tissue leiomyomas (fleshy tumors) have low malignancy and a favorable prognosis.
bubble_chart Treatment Measures
Local wide excision is the primary treatment for smooth muscle fleshy tumors. Lymph node dissection should be performed if lymph node metastasis is present, and an aggressive approach should be taken for lung metastases, aiming for resection of the metastatic tumors. Literature reports indicate that the efficacy of radiotherapy is uncertain, but it may be considered for cases with incomplete local excision. Chemotherapy can involve combination regimens with drugs such as ADM, VCR, and CTX. The prognosis for smooth muscle fleshy tumors is poor, with literature reporting a 5-year survival rate of around 20%.
The differentiation between benign and malignant smooth muscle tumors can still be challenging in some cases. Clinically, cutaneous leiomyomas with a diameter below 2.5 cm are mostly benign, while those exceeding 2.5 cm may still be benign. However, deep-seated tumors that invade muscles and fasciae are often malignant.
