Benign features of spindle cell tumors

Spindle cell tumor mainly refers to a tumor composed mainly of spindle cells. It can occur in any organ and tissue of the body. It manifests itself in the form of cancer or tumor. For example, it can occur in epithelial tissue or mesenchymal tissue. It poses a great threat to human health, especially malignant spindle cell tumors. Let us now learn about this aspect.

Benign features of spindle cell tumors

Spindle cell tumors are mainly composed of spindle cells and can occur in any organ or tissue. Their morphological manifestations can be either cancer or tumor. It can occur in epithelial tissue (such as spindle cell carcinoma, spindle cell squamous cell carcinoma) or mesenchymal tissue (such as spindle cell sarcoma, spindle cell stromal sarcoma). It has complex morphology, often similar to sarcoma, or accompanied by stromal components similar to sarcoma. The immunophenotype can be either cancer or sarcoma, or it can show a carcinosarcoma structure. This lesion is difficult to examine directly and requires multiple tests such as immunohistochemical markers.

Primary malignant spindle cell tumor is the most common bone malignancy. It originates from mesenchymal cells with osteogenic potential. The malignantly proliferating sarcoma cells directly produce neoplastic bone-like tissue or immature bone. It is also called primary malignant spindle cell tumor, which refers to a malignant connective tissue tumor in which tumor cells can directly produce tumor bone and bone-like tissue. In 1993, in order to avoid the confusion caused by the two meanings of "osteogenesis" in "origin" and "production", WHO collectively referred to them as primary malignant spindle cell tumors.

The primary malignant spindle cell tumor is osteosarcoma of the bone, second only to plasma cell myeloma in incidence. Its histological feature is that the proliferating spindle-shaped tumor cells directly produce osteoid matrix or immature bone. However, in some rare cases, the tumor cells remain in a very immature state and do not produce osteoid matrix or bone, making the classification of the tumor very difficult.

Primary malignant spindle cell tumors are highly malignant and have a very poor prognosis. Lung metastasis may occur within a few months, and the survival rate 3 to 5 years after amputation is only 5 to 20%. About three-quarters of all primary malignant spindle cell tumors occur in the lower end of the femur and the upper end of the tibia, and can also occur in other places such as the humerus, upper end of the femur, fibula, spine, ilium, etc.

The main part of the early tumor is under the periosteum and fused to the cortical bone. The tumor tissue is osteolytic and has few cartilage components. The bone is destroyed rapidly and has rich circulation. The bone necrosis area can form a package. The tumor spreads to the adjacent soft tissue and pathological fractures may occur. A few tumors have hard bone.

Generally, primary malignant spindle cell tumors do not invade joints, but occasionally involve joints after destroying the cortex or pathological fractures. Due to the development of the tumor and periosteal reaction, the periosteum is often raised to form a triangle commonly known as Codman's triangle, and there are sun-like radiating bone spicules perpendicular to the bone shaft. Under the microscope, many tumor cells, cells and nuclei are of different sizes and shapes, including small multinucleated giant cells, spindle cells, immature chondrocytes and malignant osteoblasts with large nuclei and very dark staining. Almost all metastases spread to the lungs via the blood, and a few spread to the brain, internal organs, kidneys, and lymph nodes via lymphatic vessels.