What Is a Malignant Fibrous Histiocytoma?

It is listed as the most common type of soft tissue sarcoma in recent literature reports. It contains many different types of sarcomas and has some common morphological characteristics, such as pleomorphic and matte growth patterns. Currently, it mainly includes the following three types: pleomorphic malignant fibrohistiocytoma / undifferentiated high-grade pleomorphic sarcoma, giant cell malignant fibrohistiocytoma / undifferentiated pleomorphic sarcoma with giant cells, and inflammatory malignant fibers Histiocytoma / undifferentiated pleomorphic sarcoma with significant inflammatory response.

Basic Information

English name

malignant fibrohistiocytoma

Visiting department

Oncology

Multiple groups

61 to 70 years old

Common locations

Deep soft tissue of adult limb

Common symptoms

Localized, swollen mass with bleeding and necrosis

Clinical manifestations of malignant fibrous histiocytoma

Most cases occur in the deep soft tissues of adult limbs, with peak incidence at the age of 61 to 70, but children can also develop it. Approximately half of the tumors involve deep fascia or skeletal muscle parenchyma.

Diagnosis of malignant fibrous histiocytoma

Diagnosis is based on clinical manifestations, gross examination, and histopathology. Below we will describe the different types of malignant fibrous histiocytoma.

1. Polymorphic malignant fibrous histiocytoma / undifferentiated high-grade pleomorphic sarcoma

Most are localized, swollen masses that can have a false envelope. There is a certain relationship between the size of the mass and the growth site. The maximum diameter is between 5 and 15 cm. The cut surface has various expressions, and there may be white fibrous areas or meaty texture areas, and it may be mixed with necrosis, hemorrhage, and mucoid areas.

Undifferentiated high-grade sarcoma is an exclusion diagnosis made after sufficient materials and careful use of various auxiliary examination methods. Microscopic cells and nuclei have obvious polymorphism, often accompanied by singular tumor giant cells, mixed spindle cells and round histiocyte-like cells of varying numbers. There are often woven structures and interstitial chronic inflammatory cell infiltration.

2. Giant cell malignant fibrohistiocytoma / undifferentiated pleomorphic sarcoma with giant cells

It usually appears as a large mass with bleeding and necrosis. Oval to spindle cells with varying degrees of polymorphism and obvious osteoclastic giant cell responses in the stroma can be seen under the microscope. Most diseased giant cells have no malignant manifestations.

3. Inflammatory malignant fibrous histiocytoma / undifferentiated pleomorphic sarcoma with obvious inflammatory response

Tumors are generally large and yellow in color because they often contain a large number of xanthomas. The microscope contains lamellar benign xanthoblastoma cells, a large number of inflammatory cells including neutrophils and eosinophils, and a few lymphocytes and plasma cells. Large atypical cells with one or more irregular deep stained nuclei and prominent nucleoli are scattered throughout the tumor. Most cases have a typical polymorphic MFH-like area in which spindle and polymorphic cells are randomly distributed. Inflammatory MFH is an exclusion diagnosis.

Malignant fibrous histiocytoma immunophenotype

Vimentin, 1-AAT, 1-ACT, CD68, and factor VIII are often positive and sometimes positive for actin, desmin, and lysozyme.

Malignant fibrous histiocytoma treatment

This tumor is prone to local recurrence and metastasis to distant sites, especially the lung and regional lymph nodes. Prognostic factors are related to the size and depth of the tumor.