Synovial sarcoma cellular markers are -a) Cytokeratinb) S-100c) Vimentind) Calretinin
**Core Concept**
Synovial sarcoma is a rare type of malignant tumor that typically occurs near the joints of the arm, neck, or leg. It is characterized by its unique histological and immunohistochemical features, which distinguish it from other types of sarcomas.
**Why the Correct Answer is Right**
Synovial sarcoma is known to express cytokeratin, which is a marker of epithelial differentiation. This is in contrast to other sarcomas, which typically express vimentin, a marker of mesenchymal differentiation. The expression of cytokeratin in synovial sarcoma is thought to be due to the presence of epithelial-like cells, which are a hallmark of this tumor type. Calretinin, on the other hand, is a marker of mesothelial cells and is not typically expressed in synovial sarcoma.
**Why Each Wrong Option is Incorrect**
**Option B:** S-100 is a marker of melanocytic differentiation and is not typically expressed in synovial sarcoma. While S-100 can be expressed in some sarcomas, it is not a characteristic feature of synovial sarcoma.
**Option C:** Vimentin is a marker of mesenchymal differentiation and is typically expressed in other types of sarcomas, such as leiomyosarcoma or rhabdomyosarcoma. While vimentin can be expressed in some cases of synovial sarcoma, it is not a characteristic feature of this tumor type.
**Option D:** Calretinin is a marker of mesothelial cells and is not typically expressed in synovial sarcoma. While calretinin can be expressed in some cases of malignant pleural mesothelioma, it is not a characteristic feature of synovial sarcoma.
**Clinical Pearl / High-Yield Fact**
Synovial sarcoma is a rare but aggressive tumor that typically occurs in young adults. It is characterized by its unique histological and immunohistochemical features, including the expression of cytokeratin. A high index of suspicion is necessary to diagnose synovial sarcoma, as it can mimic other types of sarcomas or soft tissue tumors.
**Correct Answer:** A. Cytokeratin.