Histological Features
Under the microscope, MFH is distinguished by its
pleomorphic appearance, meaning the cells display a wide range of shapes and sizes. The tumor is composed of
spindle cells and
giant cells, which are often arranged in a storiform or cartwheel pattern. The presence of
multinucleated giant cells and
bizarre cells with hyperchromatic nuclei are hallmarks of this malignancy. Additionally, areas of necrosis and hemorrhage are commonly observed.
Immunohistochemistry
Immunohistochemical staining is crucial for diagnosing MFH. The tumor cells often show positivity for markers such as
vimentin, which is indicative of mesenchymal origin. Other markers like
CD68 (a macrophage marker) and
alpha-1-antitrypsin may also be positive. However, the tumor cells are typically negative for epithelial markers such as
cytokeratins and
S-100 protein, helping to differentiate MFH from other soft tissue tumors.
Pathogenesis
The exact cause of MFH remains unclear, but it is believed to arise from
primitive mesenchymal cells capable of differentiating into both fibroblasts and histiocytes. Genetic mutations and chromosomal abnormalities are often implicated in its development. Exposure to radiation and certain chemicals has also been associated with an increased risk of developing MFH.
Clinical Presentation
Patients with MFH typically present with a painless, enlarging mass. The tumor can vary greatly in size and may become symptomatic if it compresses surrounding tissues. Due to its aggressive nature, MFH has a high propensity for local recurrence and distant
metastasis, particularly to the lungs.
Diagnosis
The diagnosis of MFH involves a combination of imaging studies, histological examination, and immunohistochemical staining.
Magnetic resonance imaging (MRI) and
computed tomography (CT) scans are often used to assess the extent of the tumor. A biopsy is essential for histological confirmation and to rule out other types of soft tissue sarcomas.
Treatment
Treatment options for MFH typically include surgical resection,
radiation therapy, and
chemotherapy. Wide surgical excision with clear margins is the primary treatment modality. Radiation therapy may be utilized preoperatively to shrink the tumor or postoperatively to reduce the risk of recurrence. Chemotherapy is generally reserved for metastatic or unresectable cases.
Prognosis
The prognosis for patients with MFH varies depending on factors such as tumor size, location, and the presence of metastasis. Early detection and complete surgical excision offer the best chance for a favorable outcome. However, the overall prognosis remains guarded due to the high rate of local recurrence and potential for distant metastasis.
