• Sarcomas constitute a heterogeneous group of rare solid tumors of mesenchymal cell origin with distinct clinical and pathologic features:
    • They are usually divided into two broad categories:
      • Sarcomas of soft tissues:
        • Fat, muscle, nerve and nerve sheath, blood vessels, and other connective tissues
      • Sarcomas of bone
  • Sarcomas collectively account for:
    • Approximately 1% of all adult malignancies and 15% of pediatric malignancies
  • In 2021:
    • An estimated 13,460 people will be diagnosed with soft tissue sarcoma (STS) in the United States (0.7% of all malignancies), with approximately 5350 deaths (0.9% of all cancer deaths)
  • The true incidence of STS is underestimated:
    • Especially because a large proportion of patients with gastrointestinal stromal tumors (GISTs) may not have been included in tumor registry databases before 2001
  • Prior radiation therapy (RT):
    • To the affected area is a risk factor for the development of STS
  • More than 50 different histologic subtypes of STS have been identified
  • Common subtypes of STS include:
    • Undifferentiated pleomorphic sarcoma (UPS)
    • GIST
    • Liposarcoma (LPS)
    • Leiomyosarcoma (LMS)
  • The anatomic site of the primary disease:
    • Represents an important variable that influences treatment and outcome
  • The most common primary sites include:
    • Extremities (43%)
    • Visceral (19%)
    • Retroperitoneum (15%)
    • The trunk (10%)
    • Head and neck (9%)
  • STS most commonly metastasizes to:
    • The lungs
  • Tumors arising in the abdominal cavity:
    • More commonly metastasize to the liver and peritoneum
  • Rhabdomyosarcoma (RMS):
    • Is the most common STS of children and adolescents and is less common in adults
  • Prior to initiation of treatment:
    • All patients should be evaluated and managed by a multidisciplinary team with extensive expertise and experience in the treatment of STS:
    • Because STS is rare and often complex, adherence to evidence-based recommendations is particularly important:
      • Analysis of data from 15,957 patients with STS in the National Cancer Database (NCDB):
        • Showed that NCCN Guidelines-adherent treatment was associated with improved survival outcomes
  • Pathology of Soft Tissue Sarcomas – Biopsy
    • A pretreatment biopsy is highly preferred:
      • For the diagnosis and grading of STS
    • Biopsy should be performed by an experienced surgeon or radiologist:
      • Placed along the future resection axis:
        • With minimal dissection and careful attention to hemostasis
    • The goal of biopsy is to:
      • Establish the malignancy and provide a specific diagnosis where possible and a grade where appropriate or feasible
      • Recognizing that limited biopsy material may underestimate grade
      • It may be accomplished by open incisional or core needle technique:
        • Core needle biopsy is preferred
      • However, an open incisional biopsy may be considered by an experienced surgeon
      • In patients without a definitive diagnosis following initial biopsy due to limited sampling size:
        • Repeat image-guided core needle biopsy should be considered to make a diagnosis
      • Although fine-needle aspiration (FNA) is a convenient technique:
        • It can be difficult to make an accurate primary diagnosis with FNA alone due to small specimen size and is thus discouraged
        • FNA may be acceptable in select institutions with clinical and pathologic expertise
      • Endoscopic or needle biopsy may be indicated for deep thoracic, abdominal, or pelvic STS
  • Pathologists with expertise in STS should review the pathologic assessment of biopsies and resected specimens:
    • Especially for initial histopathologic classification
    • Margins must be thoroughly evaluated in these specimens
    • Morphologic assessment based on microscopic examination of histologic sections:
      • Remains the gold standard of sarcoma diagnosis
  • The differential diagnosis of a soft tissue mass includes:
    • Malignant lesions:
      • Such as primary or metastatic carcinoma, melanoma, or lymphoma
    • Desmoids
    • Benign lesions:
      • such as lipomas, lymphangiomas, leiomyomas, and neuromas
  • However, since the identification of the histopathologic type of a sarcoma is often difficult, several ancillary techniques have been used as an adjunct to morphologic diagnosis:
    • These techniques include conventional cytogenetics, IHC, electron microscopy, and molecular genetic testing
    • Pathologists should have access to optimal cytogenetic and molecular diagnostic techniques
    • The results of appropriate ancillary studies used as an adjunct to morphologic diagnosis should be included in the pathology report
  • The pathology report should include:
    • Specific details about the primary diagnosis (using standardized nomenclature according to the WHO Classification of STS tumor)
    • The organ and site of sarcoma
    • Depth, size, and histologic grade of the tumor
    • Presence or absence of necrosis
    • Status of excision margins and lymph nodes
    • Tumor, node, and metastasis (TNM) stage
    • Additional features such as:
      • Mitotic rate, presence or absence of vascular invasion and the type and extent of inflammatory infiltration

#Arrangoiz #CancerSurgeon #HeadandNeckSurgeon #SurgicalOncologist #Sarcomas #SoftTissueSarcomas #MountSinaiMedicalCenrter #Mexico #Miami

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