Pathology Cheat Sheet
Name the Differentiation
Soft tissue tumours for NEET-PG: lipoma vs liposarcoma lipoblasts, rhabdomyosarcoma desmin, synovial sarcoma t(X;18), and GIST CD117 KIT with imatinib.
MedNext Academy | 3 min read
Name the Differentiation
Soft tissue tumours for NEET-PG: lipoma vs liposarcoma lipoblasts, rhabdomyosarcoma desmin, synovial sarcoma t(X;18), and GIST CD117 KIT with imatinib.
The classification of soft tissue tumours by line of differentiation and their diagnostic features.
High-yield lines
- Soft tissue tumours are classified by the tissue they resemble, such as fat, muscle, or fibrous tissue.
- Lipoma is the most common benign soft tissue tumour and is composed of mature adipocytes.
- Liposarcoma is a malignant fatty tumour and the well-differentiated type contains lipoblasts.
- Rhabdomyosarcoma is the most common soft tissue sarcoma of childhood and shows skeletal muscle differentiation.
- The embryonal type of rhabdomyosarcoma includes the sarcoma botryoides variant of mucosal sites.
- Rhabdomyosarcoma expresses desmin and myogenin on immunohistochemistry.
- Leiomyosarcoma is a malignant smooth muscle tumour occurring in the uterus and retroperitoneum.
- Synovial sarcoma occurs near joints in young adults and carries the t(X;18) translocation.
- Dermatofibrosarcoma protuberans is a locally aggressive skin tumour expressing CD34.
- Gastrointestinal stromal tumour arises from interstitial cells of Cajal and expresses CD117 (KIT).
- Gastrointestinal stromal tumour is driven by KIT mutation and responds to imatinib.
- Immunohistochemistry and molecular translocations are key to classifying soft tissue sarcomas.
Mapped competency codes
- PA33.3
Continue into the full chapter
This summary maps to PA33-bone-and-soft-tissue.
Frequently Asked Questions
What is the most common benign soft tissue tumour?
Lipoma, a benign tumour composed of mature adipocytes, distinguished from liposarcoma, which contains lipoblasts.
Which markers identify rhabdomyosarcoma?
Desmin and myogenin, reflecting its skeletal muscle differentiation, and it is the most common soft tissue sarcoma of childhood.
What defines gastrointestinal stromal tumour?
Origin from the interstitial cells of Cajal, expression of CD117 (KIT), driving KIT mutation, and responsiveness to imatinib.
Which translocation is seen in synovial sarcoma?
The t(X;18) translocation, characteristic of this sarcoma that occurs near joints in young adults.
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