Breast - nonmalignant
Benign tumors / changes
Granular cell tumor

Author: Monika Roychowdhury, M.D. (see Authors page)
Editorial Board Member Review: Emily S. Reisenbichler, M.D.

Revised: 9 September 2017, last major update August 2017

Copyright: (c) 2003-2017, PathologyOutlines.com, Inc.

PubMed Search: Granular cell tumor [title] breast
Cite this page: Roychowdhury, M. Granular cell tumor. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/breastgct.html. Accessed October 19th, 2017.
Definition / general
  • Tumor whose cells have granular eosinophilic cytoplasm and bland small nuclei
Essential features
  • Uncommon benign breast tumor that may present as a mass lesion
  • Imaging shows ill defined spiculated lesion mimicking malignancy
  • Microscopy shows sheets / cords of polygonal cells with abundant eosinophilic cytoplasm, round nuclei and prominent nucleoli; no mitosis or atypia seen
  • Treated by complete excision
Terminology
Epidemiology
Sites
  • Usually inner quadrant of breast
Etiology
  • Appears to derive from Schwann cells of peripheral nerves (at all sites)
Clinical features
  • Resembles invasive carcinoma clinically but almost always benign
  • Xray: suggestive of malignancy due to apparent infiltration
  • Painless lump most commonly in upper middle and medial quadrants
Radiology description
  • On mammography appears as an ill defined spiculated lesion mimicking malignancy
  • On ultrasound appears as solid, hypoechoic mass with posterior shadow
Radiology images

Images hosted on Pathout server:
Missing Image

Mammogram spot film,
image contributed by
Mark R. Wick, M.D.



Images hosted on other servers:
Missing Image

Fig 2, case 1:
ultrasonography
revealed a tumor
7 x 8 mm in size

Missing Image

Mammograph of the breast

Prognostic factors
  • Most are benign and reportedly malignant cases are rare, occurring in only 1% or 2% of cases
  • Metastasis to liver, lung, bone and axillary lymph nodes are reported with malignant granular cell tumor (J Ultrasound Med 2011;30:1295)
Case reports
Treatment
  • Local excision, local recurrence reported with incomplete excision
Gross description
  • Firm, homogenous, gray white and yellow, usually 3 cm or less and ill defined
Gross images

Images hosted on Pathout server:
Missing Image

Images contributed by Dr. Mark R. Wick

Missing Image

Dense
homogenous
tumor with
infiltrating margins



Images hosted on other servers:
Missing Image

Firm tumor with irregular borders

Missing Image

Circumscribed pinkish white mass

Missing Image

Granular cell tumor in right breast

Missing Image

52 year old woman with 1 cm nodule

Microscopic (histologic) description
  • Infiltrating sheets / cords of polygonal bland cells with well defined cell borders, abundant eosinophilic granular cytoplasm and round / oval nuclei with prominent nucleoli
  • Collagenous stroma
  • May be close to small nerve bundles and have infiltrative margins; occasional multinucleation
  • Overlying epithelium may show pseudoepitheliomatous hyperplasia
  • Rare mitotic figures, no / mild atypia
  • Histologic criteria for malignancy (proposed by Fanburg-Smith et al., Am J Surg Pathol 1998;22:779):
    • Spindling
    • Necrosis
    • Vesicular nuclei with large nucleoli
    • High N/C ratio
    • Nuclear pleomorphism
    • Increased mitotic activity
  • 1 or 2 of 6 criteria are considered atypical and 3 or more are considered to be associated with malignant behavior (Breast J 2004;10:528, Arch Pathol Lab Med 2004;128:771), but metastasis remains the only unequivocal sign of malignancy (Virchows Arch 2016;468:527)
Microscopic (histologic) images

Scroll to see all images:


Images hosted on Pathout server:
Missing Image

Images contributed by Emily S. Reisenbichler, M.D.

Missing Image

Infiltration into fat

Missing Image

S100+ tumor cells and myoepithelial cells

Missing Image

Images contributed by Dr. Mark R. Wick

Missing Image

S100, by Dr. Mark R. Wick



Contributed by Dr. Oleksandr Grygoruk, Boris Hospital and Medical Center, Kiev (Ukraine)
Missing Image Missing Image Missing Image Missing Image Missing Image


Missing Image Missing Image Missing Image Missing Image Missing Image

9 year girl with a 2 cm granular cell tumor near the left nipple, unchanged in size over past 3 years



Images hosted on other servers:
Missing Image

Core biopsy

Missing Image

Clusters of tumor cells

Missing Image

Abundant eosinophilic, granular cytoplasm


Missing Image

Mild nuclear pleomorphism

Missing Image

With DCIS and invasive ductal carcinoma

Missing Image

Beneath squamous epithelium (not necessarily breast): H&E and S100


Missing Image

PAS+

Missing Image

Compact nests of polygonal cells

Missing Image

Cells contained granular eosinophilic cytoplasm

Missing Image

IHC study showed reactivity for S100 protein

Missing Image

H&E staining of granular cells



Cytology description
  • Highly cellular, large cohesive groups and single cells mixed with connective tissue
  • Cells have ill defined, abundant granular cytoplasm and bland small nuclei with prominent nucleoli
  • No mitotic figures, no necrosis (Diagn Cytopathol 2007;35:725)
Cytology images

Images hosted on Pathout server:
Missing Image

FNAB, image
contributed by
Dr. Mark R. Wick

Positive stains
Electron microscopy description
  • Myelin figures, lysosomes
Differential diagnosis
Board review question #1
    A 45 year old woman presents with a breast mass. Excisional biopsy shows a granular cell tumor. Which one of the following is not in the differential diagnosis based on morphologic findings?

  1. Apocrine carcinoma
  2. Melanoma
  3. Metastatic renal cell carcinoma
  4. Tubular carcinoma
Board review answer #1
D. Tubular carcinomas form angulated tubular structures composed of mildly atypical ductal cells whereas granular cell tumors have sheets of large cells with abundant eosinophilic granular cytoplasm.