Epithelioid sarcoma
Encyclopedia
Epithelioid sarcoma is a rare mesenchymal soft tissue tumour with an epithelioid pattern. It often occurs in the extremities of young adults.
is made by examination of tissue, e.g. a biopsy
. The diagnosis may be delayed because of the unusual nature of the tumour and its rarity. Its histomorphology near perfectly may mimic an adenocarcinoma
, melanoma
or granuloma
.
Their immunohistochemical profile may mimic those of carcinomas; thus, these tumours may be misdiagnosed as such.
They typically stain for vimentin
and keratin
s. They characteristically have loss of staining for SMARCB1
(INI1, BAF47), and typically stain for CA125.
Diagnosis
The diagnosisDiagnosis
Diagnosis is the identification of the nature and cause of anything. Diagnosis is used in many different disciplines with variations in the use of logics, analytics, and experience to determine the cause and effect relationships...
is made by examination of tissue, e.g. 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...
. The diagnosis may be delayed because of the unusual nature of the tumour and its rarity. Its histomorphology near perfectly may mimic an adenocarcinoma
Adenocarcinoma
Adenocarcinoma is a cancer of an epithelium that originates in glandular tissue. Epithelial tissue includes, but is not limited to, the surface layer of skin, glands and a variety of other tissue that lines the cavities and organs of the body. Epithelium can be derived embryologically from...
, melanoma
Melanoma
Melanoma is a malignant tumor of melanocytes. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. They predominantly occur in skin, but are also found in other parts of the body, including the bowel and the eye...
or granuloma
Granuloma
Granuloma is a medical term for a tiny collection of immune cells known as macrophages. Granulomas form when the immune system attempts to wall off substances that it perceives as foreign but is unable to eliminate. Such substances include infectious organisms such as bacteria and fungi as well as...
.
Their immunohistochemical profile may mimic those of carcinomas; thus, these tumours may be misdiagnosed as such.
They typically stain for vimentin
Vimentin
Vimentin is a type III intermediate filament protein that is expressed in mesenchymal cells. IF proteins are found in all metazoan cells as well as bacteria. IF, along with tubulin-based microtubules and actin-based microfilaments, comprise the cytoskeleton...
and keratin
Keratin
Keratin refers to a family of fibrous structural proteins. Keratin is the key of structural material making up the outer layer of human skin. It is also the key structural component of hair and nails...
s. They characteristically have loss of staining for SMARCB1
SMARCB1
SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1 is a protein that in humans is encoded by the SMARCB1 gene.-Interactions:...
(INI1, BAF47), and typically stain for CA125.