Stromal sarcoma

Last author update: 1 March 2017
Last staff update: 24 January 2022

Copyright: 2002-2022,, Inc.

PubMed Search: stromal sarcoma breast

Emily S. Reisenbichler, M.D.
Page views in 2021: 3,701
Page views in 2022 to date: 1,837
Cite this page: Reisenbichler ES. Stromal sarcoma. website. Accessed July 6th, 2022.
Definition / general
  • Most recent WHO edition (2012) reclassified as "periductal stromal tumour" as the preferred "neutral term" in the family of fibroepithelial tumor
  • Stromal proliferation around open, benign tubules
Essential features
  • Considered a type of fibroepithelial tumor lesion with stromal proliferation around benign tubules
  • Lacks the defined tumor borders and compressed tubules of fibroadenoma and leaf-like architecture of phyllodes tumor
  • Must demonstrate stromal atypia and mitotic activity to be considered a sarcoma
Clinical features
  • Occurs in peri- and postmenopausal women (median 55.3 years), approximately 10 years older than the median phyllodes presentation (Am J Surg Pathol 2003;27:343)
  • Variable clinical presentation
Prognostic factors
Case reports
  • Given the likely relationship to fibroepithelial lesions, treatment is similar to that of phyllodes tumor
  • Wide excision with negative margins
  • As with primary breast sarcoma, assessment of axillary sentinel lymph nodes is not necessary
  • Adjuvant chemotherapy and radiation are not typically warranted unless presenting with a higher grade sarcomatous component
Clinical images

Contributed by Dr. Mark R. Wick


Gross description
  • Ill defined nodular mass (mean 3 cm)
Microscopic (histologic) description
  • Increased stromal cellularity of spindled stroma surrounding, or "cuffing" benign ducts in a pericanalicular pattern
  • Involved tubules and ducts are not malignant
  • Stromal cells demonstrate at least moderate cytologic atypia and mitotic activity
  • Infiltrative and often multinodular microscopic border
  • May be seen with areas of angiosarcomatous (Am J Surg Pathol 2003;27:343) or liposarcomatous components (Int J Surg Pathol 2015;23:221)
Microscopic (histologic) images

Contributed by Emily S. Reisenbichler, M.D.

Cytologically atypical spindled cells cuffing benign ducts

Numerous mitoses present in
cytologically atypical stromal
cells adjacent to ducts

Contributed by Dr. Mark R. Wick

Various images

Images hosted on other servers:

H&E, periductal proliferation

H&E, regular epithelial structures

Atypical cells showing mitosis


H&E, 5x

H&E, 10x

H&E, 10x

H&E, 10x

Tumor cells negative for
AE1 / AE3, CK7, CD34, S100,
beta-catenin, and desmin while
SMA was focally positive

Positive stains
  • CD34 (mostcases), CD117 (approximately ¼ of cases), HHF35 (less than 10% of cases)
Electron microscopy description
  • Undifferentiated mesenchymal cell features such as free ribosomes and irregular profiles of rough endoplasmic reticulum
  • Fibroblastic differentiation such as well organized dilated rough endoplasmic reticulum, Golgi complexes, cytoplasmic filaments and pericellular collagen (Cancer 1979;43:209)
Differential diagnosis
  • Periductal stromal hyperplasia: nodular growth, lacks the cytologic atypia and mitoses typical of a stromal sarcoma (0 - 2 mitoses per 10 high power fields)
  • Phyllodes tumor: has a more defined tumor border with compression and distortion of ductal elements causing a "leaf-like" architecture; abundant stromal overgrowth of intralobular stroma, not limited only to periductal areas
Back to top
Image 01 Image 02