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 Bone and Soft-Tissue Disorders

= HEMANGIOENDOTHELIOMA = HEMANGIOEPITHELIOMA

= neoplasm of vascular endothelial cells of intermediate aggressiveness with either benign or malignant behavior

Histo: irregular anastomosing vascular channels lined by one / several layers of atypical anaplastic endothelial cells

Age: 4th–5th decade; M÷F = 2÷1

Kaposiform Hemangioendothelioma  !!navigator!!

= locally aggressive vascular tumor of infancy

Path: infiltrative growth pattern with predominant Kaposi sarcoma–like content consisting of fascicles of spindle cells (DDx: hemangioma of infancy)

Histo: fibrinogenic thrombi in capillaries, hemorrhage, foci resembling lymphangiomatosis (⅔)

Age: 1st year of life; present at birth (½)

  • cutaneous thickening, stranding of subcutaneous fat, hemorrhage
  • ill-defined margins ← involvement of multiple tissue planes
  • destructive changes and remodeling of adjacent bone

MR:

  • signal intensity similar to muscle on T1WI
  • heterogeneously hyperintense relative to muscle on T2WI
  • apparent infiltration of subcutaneous tissues
  • signal voids on GRE ← accumulation of blood products
  • diffuse heterogeneous enhancement

Soft-tissue Hemangioendothelioma (common)  !!navigator!!

Location: deep tissues of extremities

Site: in 50% closely related to a vessel (often a vein)

Osseous Hemangioendothelioma (rare)  !!navigator!!

= EPITHELIOID HEMANGIOENDOTHELIOMA OF BONE

= rare endothelial intermediate-grade malignant vascular neoplasm

Path: well-circumscribed tumor with irregular borders

Histo: solid nests + anastomosing cords of round polygonal / spindle-shaped cells with eosinophilic cytoplasm; intracytoplasmic vacuolization (= primitive vascular channels); few mitoses, only mild pleomorphism

Average age: 2nd–3rd decade; M÷F = 2÷1

Location: calvarium, spine, pelvis, tibia (23%), femur (18%), humerus (13%); visceral involvement of lung, liver, spleen

◊Multifocal (>50%) often with regional distribution (less aggressive)

N.B.: A thorough evaluation requires CT of chest and abdomen + bone scintigraphy + skeletal survey!

Site: metaphyseal / diaphyseal >epiphyseal

  • pain + swelling of affected area

X-RAY:

  • eccentric lytic lesion WITHOUT matrix mineralization
  • osteolytic aggressively destructive area with indistinct margins (high grade)
  • well-demarcated margins with scattered bony trabeculae (low grade)
  • osteoblastic area in vertebrae, contiguous through several vertebrae
  • ± osseous expansile remodeling

CT:

  • cortical disruption with extension into soft tissues
  • joint invasion (common)
  • homogeneous enhancement

MR:

  • low to intermediate signal intensity on T1WI
  • high signal intensity on T2WI
  • homogeneous enhancement
  • NO serpentine vascular structures

Metastases to: lung (early)

Prognosis: variable course; poor prognosis with visceral involvement; local recurrence (18%); regional / distant metastasis (31%)

DDx: aneurysmal bone cyst, poorly differentiated fibrosarcoma, alveolar rhabdomyosarcoma, cystic angiomatosis, Langerhans cell histiocytosis, angiosarcoma, osteomyelitis, multiple myeloma, highly vascular metastasis, lymphoma

 Outline