Malignant fibrous histiocytoma
Encyclopedia
Pleomorphic undifferentiated sarcoma (abbreviated PUS), also undifferentiated pleomorphic sarcoma and previously malignant fibrous histiocytoma (abbreviated MFH), is a type of soft tissue sarcoma
.
It is considered a diagnosis of exclusion
for sarcoma
s that cannot been more precisely categorized.
of late adult life. It rarely occurs in children. It occurs more often in Caucasians, than those of African or Asian descent, and is a male predominant disease, afflicting two males for every female.
, but has been reported in other sites. Metastasis
occur most frequently in the lung
s (90%), bones (8%) and liver
(1%).
In the extremities, it presents as a painless enlarging soft tissue mass.
(MRI), but a biopsy
is required for the definitive diagnosis. MRI findings typically shows a well-circumscribed mass that is dark on T1-weighted images and bright on T2-weighted images. Central necrosis
is often present and identifiable by imaging, especially in larger masses.
(as the name implies) meaning they do not bear a resemblance to any normal tissue.
The histomorphology, otherwise, is characterized by high cellularity, marked nuclear pleomorphism, usually accompanied by abundant mitotic activity (including atypical mitoses), and a spindle cell morphology. Necrosis
is common and characteristic of high grade lesions.
remains controversial in MFH. The usual site of metastatic disease is the lungs, and metastases should be resected if possible.
, resectability (whether it can be cut-out completely), and presence of metastases. The five-year survival ranges from 35-60%.
Soft tissue sarcoma
A soft-tissue sarcoma is a form of sarcoma that develops in connective tissue, though the term is sometimes applied to elements of the soft tissue that are not currently considered connective tissue.-Risk factors:...
.
It is considered a diagnosis of exclusion
Diagnosis of exclusion
A diagnosis of exclusion is a medical condition reached by a process of elimination, which may be necessary if presence cannot be established with complete confidence from examination or testing...
for sarcoma
Sarcoma
A sarcoma is a cancer that arises from transformed cells in one of a number of tissues that develop from embryonic mesoderm. Thus, sarcomas include tumors of bone, cartilage, fat, muscle, vascular, and hematopoietic tissues...
s that cannot been more precisely categorized.
Epidemiology
PUS are regarded as the most common soft tissue sarcomaSarcoma
A sarcoma is a cancer that arises from transformed cells in one of a number of tissues that develop from embryonic mesoderm. Thus, sarcomas include tumors of bone, cartilage, fat, muscle, vascular, and hematopoietic tissues...
of late adult life. It rarely occurs in children. It occurs more often in Caucasians, than those of African or Asian descent, and is a male predominant disease, afflicting two males for every female.
Presentation
PUS occurs most commonly in the extremities and retroperitoneumRetroperitoneum
The retroperitoneal space is the anatomical space in the abdominal cavity behind the peritoneum. It has no specific delineating anatomical structures...
, but has been reported in other sites. Metastasis
Metastasis
Metastasis, or metastatic disease , is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research...
occur most frequently in the lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
s (90%), bones (8%) and liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
(1%).
In the extremities, it presents as a painless enlarging soft tissue mass.
Diagnosis
It can be detected by magnetic resonance imagingMagnetic resonance imaging
Magnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
(MRI), but a biopsy
Biopsy
A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...
is required for the definitive diagnosis. MRI findings typically shows a well-circumscribed mass that is dark on T1-weighted images and bright on T2-weighted images. Central necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
is often present and identifiable by imaging, especially in larger masses.
Pathology
Pleomorphic undifferentiated sarcomas are, by definition, undifferentiatedCellular differentiation
In developmental biology, cellular differentiation is the process by which a less specialized cell becomes a more specialized cell type. Differentiation occurs numerous times during the development of a multicellular organism as the organism changes from a simple zygote to a complex system of...
(as the name implies) meaning they do not bear a resemblance to any normal tissue.
The histomorphology, otherwise, is characterized by high cellularity, marked nuclear pleomorphism, usually accompanied by abundant mitotic activity (including atypical mitoses), and a spindle cell morphology. Necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
is common and characteristic of high grade lesions.
Treatment
Treatment consists of surgical excision (the extent of which ranges from tumor excision to limb amputation depending on the tumor) and in some cases radiation. ChemotherapyChemotherapy
Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....
remains controversial in MFH. The usual site of metastatic disease is the lungs, and metastases should be resected if possible.
Prognosis
Prognosis depends on the primary tumor grade (appearance under the microscope as judged by a pathologist), sizeSize
The word size may refer to how big something is. In particular:* Measurement, the process or the result of determining the magnitude of a quantity, such as length or mass, relative to a unit of measurement, such as a meter or a kilogram...
, resectability (whether it can be cut-out completely), and presence of metastases. The five-year survival ranges from 35-60%.
Human-human transmission
There is a case report of human-human transmission, in a surgeon that injured their hand while working on a PUS case.External links
- Malignant Fibrous Histiocytoma (MFH) - Sarcoma Learning Center