Anus & perianal area

Other tumors

Granular cell tumor

Editorial Board Member: Monika Vyas, M.D.
Deputy Editor-in-Chief: Aaron R. Huber, D.O.
Harmeet Kharoud, M.B.B.S., M.P.H.
Raul S. Gonzalez, M.D.

Last author update: 9 January 2024
Last staff update: 9 January 2024

Copyright: 2002-2024,, Inc.

PubMed Search: Granular cell tumor

Harmeet Kharoud, M.B.B.S., M.P.H.
Raul S. Gonzalez, M.D.
Page views in 2023: 1,381
Page views in 2024 to date: 1,074
Cite this page: Kharoud H, Gonzalez RS. Granular cell tumor. website. Accessed June 16th, 2024.
Definition / general
  • Rare, benign anal neoplasm with neuroectodermal differentiation derived from Schwann cells and composed of epithelioid cells with abundant granular cytoplasm
Essential features
  • Benign tumor with neuroectodermal differentiation
  • Composed of oval to polyhedral cells with abundant eosinophilic granular cytoplasm
  • Positive for S100 and CD68
  • Older terms, not recommended: Abrikossoff tumor, granular cell myoblastoma, granular cell schwannoma, granular cell nerve sheath tumor
ICD coding
  • ICD-O
    • 9580/0 - granular cell tumor NOS
    • 9580/3 - granular cell tumor, malignant
  • ICD-10: D12.9 - benign neoplasm of anus and anal canal
  • ICD-11
    • 2E8Y & XH09A9 - other specified benign mesenchymal neoplasm & granular cell tumor, NOS
    • XH90D3 - granular cell tumor, malignant
  • Inactivating somatic mutations in the endosomal pH regulators ATP6AP1 and ATP6AP2 are seen in 72% of granular cell tumors (Nat Commun 2018;9:3533)
  • Abnormal RAS-MAPK pathway cell signaling may be linked in granular cell tumors associated with syndromes (Clin Genet 2009;75:185)
Clinical features
  • Mostly discovered incidentally during endoscopy for other reasons, though may cause symptoms such as perianal discomfort, ulceration and bleeding
  • Slow growing, painless anal lesion presenting as a polyp
  • Tissue sampling
Radiology description
Radiology images

Images hosted on other servers:
MRI of perianal mass

MRI of perianal mass

Ultrasound of perianal mass

Ultrasound of perianal mass

Prognostic factors
Case reports
  • Local excision
Clinical images

Images hosted on other servers:
Anal polypoid mass

Anal polypoid mass

Peranal cutaneous nodule

Perianal cutaneous nodule

Gross description
  • Poorly circumscribed, firm, tan-yellow to tan-white nodule
Gross images

Images hosted on other servers:
Excision of perianal tumor

Excision of perianal tumor

Microscopic (histologic) description
Microscopic (histologic) images

Contributed by Raul S. Gonzalez, M.D.
Gastroesophageal junction lesion Gastroesophageal junction lesion

Gastroesophageal junction lesion

Pseudoepitheliomatous hyperplasia








Electron microscopy description
Electron microscopy images

Images hosted on other servers:
Ultrastructural view

Ultrastructural view

Molecular / cytogenetics description
  • Soft tissue cases often have loss of function mutations in ATP6AP1 and ATP6AP2; anal cases have not been tested
Sample pathology report
  • Anal, mass, resection:
    • Granular cell tumor, 1.1 cm (see comment)
    • Surgical margins negative for tumor
    • Comment: Immunohistochemical stains show the tumor is positive for S100 and CD68. Granular cell tumors are rare in the anus but have been reported.
Differential diagnosis
  • Adult rhabdomyoma:
    • Benign tumor with skeletal muscle differentiation
    • Also shows round cells with eosinophilic cytoplasm
    • Cells show multiple nuclei and peripheral cross striations
    • Positive for desmin, muscle specific actin, myoD1, myoglobin
  • Alveolar soft part sarcoma:
    • Malignant tumor that consists of round cells with abundant eosinophilic granular cytoplasm
    • Classic alveolar pattern and degree of nuclear atypia with prominent nucleoli should exclude granular cell tumor
    • Usually negative for S100 and CD68
  • Squamous cell carcinoma:
    • Most common malignancy of anus
    • Architecture of pseudoepitheliomatous hyperplasia overlying granular cell tumor may mimic malignancy
    • Squamous cell carcinoma shows clear cytologic atypia
Board review style question #1

A 55 year old woman presents with a painless 2 cm perianal mass, which is excised. It is positive for S100 and CD68. Which of the following is the most likely diagnosis?

  1. Alveolar soft part sarcoma
  2. Gastrointestinal stromal tumor
  3. Granular cell tumor
  4. Squamous cell carcinoma
Board review style answer #1
C. Granular cell tumor. The histologic appearance and immunohistochemical profile are consistent with granular cell tumor. Answers A, B and D are incorrect because the other lesions are negative for S100 and CD68. Alveolar soft part sarcoma and squamous cell carcinoma would show more cytologic atypia and gastrointestinal stromal tumor would likely be spindled.

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Reference: Granular cell tumor
Board review style question #2
Which of the following statements is true for granular cell tumor of the anus?

  1. It can never metastasize
  2. It is a fast growing painful lesion that infiltrates into the surrounding structures
  3. It is the most common site for granular cell tumors in the digestive tract
  4. It may arise in syndromic patients
Board review style answer #2
D. It may arise in syndromic patients. Multiple granular cell tumors can occur in patients with Noonan syndrome, LEOPARD syndrome and neurofibromatosis 1. The anus is a potential site. Answer B is incorrect because granular cell tumors are slow growing and painless. Answer A is incorrect because they very rarely metastasize. Answer C is incorrect because the esophagus is the most common site for digestive tract granular cell tumors.

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Reference: Granular cell tumor
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