Breast nonmalignant
Benign tumors

Topic Completed: 1 March 2016

Minor changes: 6 September 2019

Copyright: 2002-2019,, Inc.

PubMed Search: Hemangiopericytoma [title] breast

Monika Roychowdhury, M.D.
Page views in 2019: 2,034
Page views in 2020 to date: 4,410
Cite this page: Roychowdhury M. Hemangiopericytoma . website. Accessed May 27th, 2020.
Definition / general
  • Rare, low grade malignant tumor with circumscribed area of bland spindled cells with branching and staghorn vessels
  • Originally regarded as a vascular, pericyte derived tumor; recently categorized by WHO as a fibroblastic tumor similar to solitary fibrous tumor
Essential features
  • Low grade malignant tumor composed of branching / staghorn vessels and bland spindled cells
  • Complete excision with negative margins is considered curative
  • Aggressive behavior suggested if large ( > 5 cm), necrosis, mitosis, infiltrative margins
  • Very rare
  • Usually women 33 - 67 years
  • Originates from capillary pericytes
Clinical features
  • Painless, firm nodule / mass, not attached to the skin
Radiology images

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Well circumscribed mass

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Hypoechoic lesion

Prognostic factors
  • Nuclear atypia, high cellularity or necrosis, increased mitotic index ( > 4/10 HPF), large tumor size ( > 5 cm) and infiltrative margins are considered criteria for malignancy and also correlate with local recurrence and metastatic disease
Case reports
  • Complete local excision with negative margins
  • Inadequate data regarding lymph node dissection; in general, lymph node metastases are rare
  • Mastectomy may be necessary for large lesions (Mod Pathol 1988;1:98)
Microscopic (histologic) description
  • Thin walled, staghorn type vessels separated by polygonal cells with indistinct margins, pale cytoplasm and small round / oval nuclei
  • May have areas of hemorrhage and cystic degeneration
  • Variable mild increase in mitosis
Microscopic (histologic) images

AFIP images
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Thin walled staghorn type vessels

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Fusiform tumor cells

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CD34 and vimentin

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Pectoralis major mass

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Sinonasal tumor

Cytology description
  • Cellular
  • Single and tightly packed clusters of oval to spindled cells aggregating around branched capillaries
  • Usually basement membrane material is present
  • Nuclei are uniform and oval with finely granular chromatin and indistinct nucleoli
  • No mitotic figures, no necrosis (Cancer 1999;87:190)
  • Positive stains
    Negative stains
    Electron microscopy description
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