Neurogenic Sarcoma (Malignant Peripheral Nerve Sheath Tumor)

Neurogenic Sarcoma (Malignant Peripheral Nerve Sheath Tumor)
Key Facts
Clinical Issues
  • Extremely rare tumor
  • Often associated with neurofibromatosis
  • Tumors may be central or peripheral
  • Tumors may arise in endobronchial location
  • Aggressive behavior with recurrences and metastases
Microscopic Pathology
  • Fascicular atypical spindle cell proliferation
  • Frequent “herringbone” pattern of growth
  • Alternating hyper- and hypocellular areas
  • Rhabdomyoblastic differentiation may be present (malignant “triton” tumor)
  • Frequent areas of cystic degeneration, hemorrhage, and necrosis
  • Prominent myxoid stromal changes
Ancillary Tests
  • S100 protein is of limited utility for diagnosis because expression is lost or only focal in malignant neural neoplasms
  • Immunohistochemical staining has very low specificity for diagnosis of neurogenic sarcoma
  • Shows complex interdigitating cytoplasmic processes covered by basal lamina material on EM
Diagnostic Checklist
  • Immunohistochemical staining may be of very limited value for diagnosis in neurogenic sarcoma
  • 2 most reliable features for establishing diagnosis are a history of neurofibromatosis and ultrastructural findings
Gross appearance of primary neurogenic sarcoma of the lung in a resected specimen shows a fleshy, well-circumscribed tumor mass with extensive areas of hemorrhage and a glistening cut surface.
Neurogenic sarcoma of the lung shows well-circumscribed spindle cell tumor in lung parenchyma. Clinical history and special stains are required to separate this from other primary and metastatic tumors.
TERMINOLOGY
Synonyms
  • Malignant peripheral nerve sheath tumor
  • Malignant schwannoma
Definitions
  • Primary malignant lung neoplasm showing evidence of peripheral nerve sheath differentiation
CLINICAL ISSUES
Epidemiology
  • Incidence
    • Extremely rare tumor
    • Often associated with neurofibromatosis
  • Age
    • Affects all age groups
    • Most frequent in young adults and middle-aged patients (30-50 years of age)
  • Gender
    • No sex predilection
Presentation
  • Large intraparenchymatous mass
    • Tumors may be central or peripheral
    • Tumors may arise in endobronchial location
  • Shortness of breath
  • Cough
  • Chest pain
  • Small peripheral tumors may be asymptomatic and discovered incidentally
Treatment
  • Surgical approaches
    • Surgical excision
  • Adjuvant therapy
    • Chemotherapy and radiation therapy may be employed for advanced or unresectable cases
Prognosis
  • Aggressive behavior with recurrences and metastases
  • Usually rapidly progressive course with fatal outcome
MACROSCOPIC FEATURES
General Features
  • Large, fleshy, gray-white, lobulated tumor
  • May be partially encapsulated
  • Frequent hemorrhage and necrosis
Sections to Be Submitted
  • Submit at least 1 section per centimeter of largest tumor diameter
Size
  • Usually large (> 5 cm in greatest dimension)
MICROSCOPIC PATHOLOGY
Histologic Features
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Jul 9, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Neurogenic Sarcoma (Malignant Peripheral Nerve Sheath Tumor)

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