Malignant fibrous histiocytoma

Introduction to malignant fibrous histiocytoma Malignant fibristiocytoma (malignantfibrohistiocytoma), also known as malignanthistiocytoma, is the most common soft tissue tumor in the elderly. This tumor is a pleomorphic, highly cellular tumor, some of which are stored in fat. Quality, vacuolization is obvious, mitosis is common, some are atypical, cell Vimentin staining positive, recurrence rate after surgical resection is 25%, 35% metastasis, survival rate is 50%, in recent years, it has been found Variants of this tumor include polymorphic stratification, mucinous type, giant cell type, inflammatory type, and hemangioma-like type. basic knowledge The proportion of illness: 0.005% Susceptible people: more common in the 50-70 years old Mode of infection: non-infectious Complications: extra-chondral chondrosarcoma epithelioid sarcoma

Cause of malignant fibrous histiocytoma

Physical and chemical factors (65%)

It is generally believed that malignant fibrous histiocytoma is derived from undifferentiated mesenchymal cells and differentiates into fibroblasts and histiocytes. The malignant fibrous histiocytoma of soft tissue is the same as the lesion in bone, which can be secondary to radiotherapy. The foregoing phenomenon has been found in the site of radiation therapy for breast cancer glands, malignant lymphoma, plasma cells and Hodgkin's disease. The mass is often multi-lobed, gray-white, sometimes yellow or yellow-brown (lipid, hemosiderin) in the mass, especially in mucosal variants with a gelatinous area, in the aneurysm-like type of hemorrhagic lesion It has an advantage and is accompanied by a large cavity filled with blood. In the inflammatory lesions, yellow is particularly obvious, and sometimes bleeding and necrosis are extensive, so that the whole tumor mass becomes a fluid-containing capsule similar to a cystic hematoma, sometimes The appearance of the tumor appears to be completely coated, but in fact, the lesion has infiltrated into the surrounding tissue.

Pathogenesis

(1) Polymorphic layered type

Histological manifestations are characterized by significant cellular pleomorphism, spindle-shaped, oval and giant cells, which can be both benign and malignant. These cells have morphological changes, distinct mitosis, and staining. Deep nucleus, large chromatin and large nucleoli and other atypicalities are common in this type of lesion. Sometimes, giant cells, mononuclear and spindle cells have densely stained eosinophilic cytoplasm, accompanied by early stage. Muscle-like, but visible from stripe-like images without traverse.

The multi-formation of the above cells may also be the main component of the formation of lesions, but at the same time there is a so-called stratification change. The spindle cells and collagen fibers are mostly arranged in a spiral or windmill shape, often in the center of which is formed by collagen or small blood vessels. The blush area radiates to the surroundings, and silver staining of the spindle cells shows a particularly pronounced reticular pattern that surrounds a single cell, while in areas where tissue cells predominate, outsourcing around small cell tissue, in the center of the stratified area, The argyrophilic performance is particularly pronounced. Since the lesion contains lipids, foam cells of varying contents can be seen, and sometimes acute and/or chronic inflammatory infiltration can be seen.

Cytoplasmic PAS staining is positive, but quite irregular, and more variable, and mainly resistant to amylase and hyaluronidase (as mucopolysaccharide rather than glycogen), in the same tumor, can be dominant in polymorphic changes Typical stratified and collagenated appearances were found on the side of the area.

Malignant fibrous histiocytoma must be differentiated from all tumors with significant polymorphism, especially the very rare polymorphic rhabdomyosarcoma, which is difficult to see horizontal stripes and can be expressed as striated muscle cells under electron microscope; In addition, PAS-positive (glycogen), which is sensitive to starch acid, is clearly unchanged.

The differential diagnosis of this disease and pleomorphic liposarcoma is difficult. The latter has no stratification, but there are differentiation of adipogenic cells and adipocytes. There may also be intracytoplasmic vacuoles in malignant fibrous histiocytoma, but In adipocytes, vacuoles can transfer to and around the nucleus and flatten the nucleus. In addition, mucopolysaccharide is contained in the vacuoles formed by malignant fibrous histiocytoma cells, due to the two tumors (the former and polymorphism). Lipid staining of liposarcoma is positive, so it does not make any sense for differential diagnosis.

It is also possible to present the appearance of malignant fibrous histiocytoma in undifferentiated and polymorphic carcinomas. In these tumors, special staining of glycogen and leprosa, and searching for epithelial differentiation regions by electron microscopy, have a definite diagnostic effect.

Protuberant cutaneous fibrosarcoma, located in the skin, and has its clinical features, such as a diffuse stratified appearance, without polymorphic cells, low-grade malignant histology, and no necrosis, according to the above clinical manifestations It can be differentiated from malignant fibrous histiocytoma. The only diagnosis between the two is that the former is in the skin and the morphology is small without necrosis.

(2) Mucus-like variation

Weiss and Enzinger (1977) believe that one of the important basis for determining mucus-like variants is that the former contains more than half of the mucin-like components of the entire tumor, and the malignant fibrous histiocytoma of the mucoid-like altered area is characterized by polymorphism and stratification. Arranged next to the area, sometimes the histological structure of the two can be clearly separated. Sometimes, it is mixed together, and the accumulation of intracellular or extracellular mucopolysaccharides can greatly change the appearance of the tumor, which is bundled or layered. The pattern can be reduced accordingly, or all disappeared, the blood vessels show clearer, the cells contain vacuoles, and no stratified changes in the mucus-like area are seen; the blood vessels are cluster-like, so that it is difficult to be associated with mucinous liposarcoma Identification, the cells forming vacuoles may also be similar to fat mother cells. The difference between the two is that the former contains mucopolysaccharidase, which generally has the characteristics of low-grade malignant tumors. In fact, the polymorphism of polymorphic cells Not very significant, but plexiform vascular proliferation is more widespread and typical, in the case of highly malignant mucinous liposarcoma or pleomorphic liposarcoma, there is no code Malignant fibrous histiocytoma unique layered appearance.

In fibrosarcoma, mucus-like lesions may also be present, but fibrosarcoma is a single-morphous spindle-shaped cell proliferation and arranged in a "human" shape. In pseudocortical lesions with a mucinous appearance, it is necessary to Segmental fasciitis is discussed. The latter structure is similar to the formation of granular tissue; the curve of the blood vessel changes (in the form of an "S" shape) and the unclear atypical mitotic image is helpful for diagnosis.

Finally, muscle myxoma is different from mucinous malignant fibrous histiocytoma due to avascular hyperplasia and malignant cellular components.

(3) Giant cell variation

Such mutations, as discussed by Enzinger et al. in 1972, are characterized by distinct giant cell components, which proliferate and aggregate into a number of small nodules that fuse with each other. Significant giant cells have typical and atypical nuclei, inflammation. The change of superiority is more obvious around the multiple necrotic areas. Sometimes, around the new nodules, there is osteochondral metaplasia of connective tissue.

(4) Inflammatory variation

In 1935, Oberling named the retroperitoneal lesion "yellow granuloma", kiriakoj and kemp. In 1972, it was confirmed to be an inflammatory malignant fibrous histiocytoma, and its cellular components and cellular components in the polymorphic type were paralyzed, but In this disease, the composition of xanthoma and inflammation is dominant.

In histology: tissue cell-type cells are filled with lipids (yellow tumor cells), showing varying degrees of pleomorphism and atypicality, combined with inflammatory components to varying degrees without necrosis; in addition, lymphocytes, mononuclear The cells and granulocytes are mainly composed of vascular components. Therefore, it can be seen as granulation tissue. If more lesion specimens are examined, it can be found as a polymorphic stratified region based on the diagnosis of malignant fibrous histiocytoma.

The differential diagnosis must include stratified pleomorphic malignant fibrous histiocytoma and fibrosarcoma with particularly prominent inflammatory components. When the inflammatory component is particularly obvious, it must be differentiated from polymorphic malignant fibrous histiocytoma and fibrosarcoma. In both tumors, the inflammatory component coexists with the necrotic area in most cases, and the most important is the non-expanding xanthoma component. Another non-tumor inflammatory/granuloma is differentiated from the disease. The procedure, so in order to clarify the nature of its malignant changes and the need for differential diagnosis, the specimens to be examined should be taken as much as possible when performing pathological examinations.

(5) hemangioma variation

The hemangioma variants occur mostly in children and early adulthood and must be differentiated from malignant hemangioma, which was identified by Enzinger in 1979 as three typical manifestations: 1 more tissue-intensive cells occurring in the cord or vesicle of the fusion zone Area; 2 cystic-hemorrhagic lesion similar to aneurysmal bone cyst; 3 diffuse inflammatory infiltration.

Inflammatory components usually form a layered structure around the tumor. The vascular necrosis and hemorrhage area account for most of the tumor, and are often located in the center. There is no endothelial lining in the vascular lumen. The basal cells are mononuclear or multinuclear tissue cells. There are fake sacs around it.

(6) Tissue cell variation

Tumors are mainly composed of spherical cells. The outer circumference of the round nucleus sometimes surrounds the serrated outer membrane. Usually, the larger nucleoli and the eosinophilic cytoplasm are visible. The cells have the characteristics of phagocytic activity and the appearance of stratification. It rarely occurs, and it occurs indiscriminately. Giant cells, foam cells and spindle cells appear simultaneously with these basal cells, and multiple bad areas and inflammatory lymphocyte mononuclear cells infiltrate.

Tissue cell variants need to be differentiated from epithelioid sarcoma, which has a typical pseudo-granulation-like change in the superficial site and is associated with central necrosis; in deep-onset patients, the cells are nodular and beaded. In addition, it needs to be differentiated from the metastasis of undifferentiated carcinoma and large cells of malignant lymphoma.

Malignant fibrous histiocytoma prevention

There are no special and effective preventive measures, and some adjustments can be made in the diet:

(1). Maintain ideal weight.

(2). Ingest a variety of foods.

(3). The daily diet includes a variety of vegetables and fruits.

(4). Ingest more high-fiber foods (such as whole grain cereals, beans, vegetables, and fruits).

(5). Reduce total fat intake.

(6). Limit the intake of alcoholic beverages.

(7). Limit the intake of pickled, smoked, and nitrite-containing foods.

Malignant fibrous histiocytoma complications Complications of extra-osseous chondrosarcoma epithelioid sarcoma

As the tumor enlarges, symptoms of compression of other organs may occur.

Malignant fibrous histiocytoma symptoms common symptoms soft tissue swelling anorexia

One of the most common soft tissue malignancies, due to the recent classification into my sexual rhabdomyosarcoma in recent years, pleomorphic liposarcoma and rare sparsely differentiated fibrosarcoma are all classified as malignant fibrous histiocytoma, so The number of cases increases, and the scope is expanded. According to the needs of clinical work, the above-mentioned lesions are divided into several varieties. Usually, when the polymorphic sarcoma without special cell differentiation changes is repeatedly examined, the malignant fibrous histiocytoma is displayed. Morphological characteristics, malignant fibrous histiocytoma is clearly prevalent in men.

The age of onset is relatively late, generally from 50 to 70 years old, only hemangioma-like patients can develop before the age of 20.

Malignant fibrous histiocytoma occurs in the limbs (especially in the lower limbs, especially in the thighs) and the latter in the peritoneum is mainly an inflammatory variant. More than 90% of the lesions are deeper, mostly under the fascia, about 10 % of lesions occur in superficial areas. Conversely, aneurysm-like (variants) occur in the skin and subcutaneous tissue of the limb.

For the gradual growth of spherical lumps in the deeper layers, sometimes it grows slowly, sometimes very fast, and generally has no pain symptoms, usually from the time of swelling to the time of diagnosis, ranging from several months to several years. It is difficult to diagnose the latter in the peritoneum. And later, symptoms include anorexia, weight loss, and compression of the abdominal organs. It is easier to diagnose lesions located on the fascia. When the tumor is medium in size, it can be found, sometimes the cystic changes and/or hemorrhage. It may be misdiagnosed as a hematoma.

Clinically similar to stellate fibrosarcoma, a bulging round tumor with a diameter of 1cm to several centimeters, often with a reddish or dark black color and progressive enlargement. The tumor is deep, mostly located in the subcutaneous tissue, and 1/3 of the patients occur in The thighs and buttocks, sometimes based on radiation dermatitis or chronic ulcers, have a peak onset of 20 years.

The prognosis of this disease is related to the location of the disease. The prognosis of the tumor is relatively poor in the tumor and the proximal end of the limb. The prognosis of the tumor based on radiation dermatitis is particularly poor. The recurrence rate after surgical resection is 25%, 35% metastasis, survival. The rate is 50%.

Examination of malignant fibrous histiocytoma

Pathological examination

The tumor is a pleomorphic, highly cellular tumor. Some cells have a fusiform nucleus that is arranged in an interlaced vortex-like manner with very little cytoplasm. Therefore, these cells are fibroblast-like, with a small amount visible between them. Collagen, other cells are polygonal, with irregular nucleation and a large amount of eosinophilic or vacuolated cytoplasm. These cells are tissue-like, some of which are vacuolized due to the storage of lipids. Foam cell-like, in addition, there are still multi-nuclear giant cells that are singular, large and deeply stained. The mitosis is common, some are atypical, and the cells are positive for Vimentin staining.

The tumor has multiple subtypes: mucin-like, inflammatory, hemangioma-like, and giant cell.

1. Mucin-like subtypes: large areas with relatively few cells see wide gaps, and fusiform and stellate cells are located in a matrix rich in acidic mucopolysaccharides.

2. Inflammatory subtypes: diffuse dense neutrophil infiltration, no tissue necrosis, and in some inflammatory malignant fibrous histiocytoma, many foam cells as seen in fibrosporous sarcoma And singular giant cells containing lipids.

3. Aneurysmal-like subtype: There is a large area of hemorrhage in the cyst-like space, and the adjacent vascular space is significant.

4. Giant cell subtype: In addition to pleomorphic malignant giant cells, there are still osteoclast-like giant cells with abundant cytoplasm and uniform cell size.

X-ray examination

In a few cases, when the tumor is close to the bone, it may show superficial osteolysis or periosteal reaction. The bone scan is sensitive to the adjacent bone reaction. The calcification and ossification of the lesion are rarely seen, but sometimes it is also in the tumor. Seen around or within the tumor, angiography can show changes common to other malignant tumors, but sometimes even in very large tumors, due to tissue necrosis and hemorrhage, it appears as avascular image, the main blood vessels may move Position and pressure, but rarely infiltrated, CT and MRI show solid, heterogeneous masses, sometimes large fluid-containing cysts.

Diagnosis and diagnosis of malignant fibrous histiocytoma

diagnosis

According to the clinical manifestations, the characteristics of skin lesions and histopathological features can be diagnosed.

Differential diagnosis

In imaging, it must be differentiated from fibrosarcoma, osteolytic osteosarcoma, lymphoma, osteolytic bone metastasis, and histologically, fibrous fibroids (multiple spindle cells, tibial-like structures), osteosarcoma (neoplastic osteogenesis) identification, similar to the malignant fibrous histiocytoma area seen in fibrosarcoma and osteosarcoma, further study, in the case of the diagnosis of malignant fibrous histiocytoma is not certain or unclear, the diagnosis must be based on Adequate and large number of histological sections. In addition, the histological differential diagnosis of malignant fibrous histiocytoma also includes bone metastasis of cancer. Their longer cells are arranged in a fuzzy lamellar structure, while the cells of malignant fibrous histiocytoma are also It may have an epithelial appearance and may aggregate into a group of vesicles.

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