Soft tissue
General
Sarcomas - general

Author: Komal Arora, M.D. (see Authors page)

Revised: 25 July 2016, last major update July 2012

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Sarcomas [title] soft tissue

Definition / General
  • 9,500 new cases per year in US
  • Classified based on type of cellular differentiation, although most arise from multipotent mesenchymal cells that then differentiate along various cell lines
  • Diagnostic errors are often due to lack of familiarity with rare lesions, not failure to perform immunostains (Am J Clin Pathol 2001;116:473)

WHO classification:
Clinical Features
  • Usually arise de novo, not from benign tumors (MPNST may be an exception)
  • Do not appear to arise from trauma
  • May be caused by radiation therapy (MFH, extraskeletal osteosarcoma), foreign bodies (MFH, angiosarcoma) or chemical carcinogens (angiosarcoma)
  • Recommended to diagnose with FNA, core biopsy or incisional biopsy so appropriate treatment can be determined in advance
  • Congenital soft tissue tumors, even with high grade features, rarely have malignant behavior
  • Nodal involvement uncommon
  • Local recurrences show increased number of genetic changes, including loss at 9p, gains at 5p and 20q (Mod Pathol 2001;14:978)

Poor prognostic factors:
  • Large size, deep seated versus superficial, retroperitoneum versus extremities, high grade, high stage, positive margins (associated with local recurrence)
Laboratory
Fine needle aspiration:
  • Most specimens are recognized as sarcoma, and subtyping is most accurate in bone sarcomas and pediatric sarcomas
  • Subtyping is often not possible in adult specimens, but this usually does not affect initial therapy (Am J Clin Pathol 2001;115:59)
  • For staging information, click here
Treatment
  • Ideally wide local excision with 1 - 2 cm margin of normal tissue
  • If not possible due to anatomic constraints (neurovascular bundle, bone), a marginal excision (through pseudocapsule) or focally positive margin is acceptable
  • Surgery should also remove site of prior incision
  • Pre- or postoperative radiotherapy are routinely used for large, high-grade tumors or disseminated disease
  • Amputation is reserved for unresectable tumors
  • Surgical resection of pulmonary metastases often has value