Breast

Other benign tumors

Granular cell tumor


Editorial Board Member: Emily S. Reisenbichler, M.D.
Monika Roychowdhury, M.D.

Last author update: 1 August 2017
Last staff update: 1 March 2024

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PubMed Search: Granular cell tumor [title] breast

Monika Roychowdhury, M.D.
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Cite this page: Roychowdhury M. Granular cell tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/breastgct.html. Accessed March 19th, 2024.
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

Contributed by Mark R. Wick, M.D.
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Mammogram spot film



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

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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

Contributed by Mark R. Wick, M.D. and AFIP
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Dense
homogenous
tumor with
infiltrating margins

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Various images



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Firm tumor with irregular borders

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Granular cell tumor in right breast

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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

Contributed by Emily S. Reisenbichler, M.D., Mark R. Wick, M.D., Dr. Oleksandr Grygoruk, AFIP and @ThatGlassTho on Twitter
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Infiltration into fat

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S100+ tumor cells and myoepithelial cells

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Granular cell tumor

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Various images


Various images

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S100

Granular cell tumor Granular cell tumor Granular cell tumor

Granular cell tumor


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


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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:
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Core biopsy

Abundant eosinophilic, granular cytoplasm

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


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Compact nests of polygonal cells

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Cells contained granular eosinophilic cytoplasm

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IHC study showed reactivity for S100 protein

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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

Contributed by Mark R. Wick, M.D.
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FNAB

Positive stains
Electron microscopy description
  • Myelin figures, lysosomes
Differential diagnosis
Board review style 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 style 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.

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Reference: Granular cell tumor
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