Sarcoma Pathology


  • Classified as tumors with differentiation toward features of any mesenchymal supportive or muscular tissue
  • Vimentin typically is expressed in mesenchymal cell although under pathological conditions can be expressed in other cell types.
  • The ratio of benign to malignant tumors is more than 100:1.
  • Do not arise in situ; do not originate from benign soft tissue tumors
  • Most common type MFH


Relative incidence of histologic types

Type %
MFH 23
Fibrosarcoma 14
Liposarcoma 18
Leiomyosarcoma 10
Synovial cell 8
Neurosarcoma 8
Rhabdomyosarcoma 9
Unclassified 10

*Incidence variable with series


  • Single most important factor in determining prognosis; requires experienced pathologist
  • Cellular differentiation may be the most important histological variable in determining grade.
  • Others important factors include pleomorphism, necrosis, mitoses, aneuploidy
  • Several systems (Broders – 4 grade, AJCC – 3 grade, Memorial – binary).
  • Pathologists disagree ~20% of the time on grade

For all tumor types, distant metastases increases steeply with grade (rare for grade 1; ~ 40% at 5yr for grade 3)
Markers/ Molecular Pathogenetics
None provides a definitive diagnosis
Pathologist must integrate information from H&E, EM, as well as molecular analysis

PNET (Not a sarcoma) three likely candidates

  • neural crest
  • primordial germ cells
  • uncommitted mesenchymal cells
  • neuron-specific enolase
  • neurofilament
  • HNK-l (Leu-7)
  • S-100 protein,
  • MB2 * t(11;22)(q24;q12)

Synovial Sarcoma

  • Epithelial
  • spindle cell
  • Keratin - Epithelia
  • vimentin + BCL-2 for spindle cells
  • t(X;18)(p11:q11)


  • Striated muscle
  • myoglobin
  • t(2;13)(q35;q14)
  • t(1;13)(p36;14)

Malignant Fibrous Histiocytoma

Familial adnomatous polyposis (FAP) & Desmoid Tumor (Aggressive Fibromatosis = Extra-abdominal desmoid tumor)

  • Gardner’s (FAP) - is characterized by colorectal adenomatous polyps and soft and hard tissue neoplasms. The former may number in the hundreds to thousands.
  • Both Gardner’s and FAP have APC gene.
  • Desmoid Tumor is 10-15% of FAP patients and also share APC gene.
  • Although desmoid tumors can arise in any skeletal muscle, they most commonly develop in the anterior abdominal wall and shoulder girdle.
  • Retroperitoneal neoplasms are more common in familial polyposis coli and Gardner syndrome after abdominal surgery than in other conditions (Raynham, 1971).

Malignant schwannoma

  • MIB-1/Ki6 proliferative index and PCNA (proliferating cell nuclear antigen)
  • Tumors with a high proliferative status may have a short preoperative symptom duration, while tumors with a low proliferative status may have a long symptom duration.
  • Neurofibromaoses (NF1) predisposed to optic nerve glioma, neurofibroma, neurobibrosarcoma, malignant schwannoma, astrocytoma, and pheochromocytoma.
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