Anus & perianal area
Other tumors
Granular cell tumor
Author: Elliot Weisenberg, M.D.
Last author update: 1 May 2014
Last staff update: 15 October 2021
Copyright: 2002-2023, PathologyOutlines.com, Inc.
PubMed Search: Anus granular cell tumor
Table of Contents
Definition / general | Terminology | Epidemiology | Sites | Clinical features | Prognostic factors | Case reports | Treatment | Clinical images | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Electron microscopy description | Differential diagnosisCite this page: Weisenberg E. Granular cell tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/anusGCT.html. Accessed September 30th, 2023.
Definition / general
- WHO definition of granular cell tumor: a benign tumor showing neuroectodermal differentiation and composed of large, oval to round cells with copious eosinophilic, distinctly granular cytoplasm (Fletcher: WHO Classification of Tumours of Soft Tissue and Bone, 4th Edition, 2013)
- Note: rarely has malignant behavior
Terminology
- Synonyms and obsolete terms include granular cell schwannoma, granular cell nerve sheath tumor, granular cell myoblastoma, Abrikossoff tumor
Epidemiology
- Overall, granular cell tumor is not an unusual lesion; it is found in the skin, subcutaneous tissue and submucosa
- Most commonly located in head and neck (especially the tongue), trunk, proximal extremities
- Less common at other locations
- Occurrence in anus and perianal region is quite rare
- May occur at any age but most common in adults from 30 to 60 years
- Different sources report increased incidence in both men and women (Fletcher: WHO Classification of Tumours of Soft Tissue and Bone, 4th Edition, 2013, Weiss: Enzinger and Weiss's Soft Tissue Tumors, 5th Edition, 2007)
- Very rarely associated with tumor syndromes
Sites
- In anal mucosa or perianal skin
- May be found near peripheral nerves
Clinical features
- May present as asymptomatic nodule or polyp or may mimic hemorrhoids causing pain, bleeding, discomfort
Prognostic factors
- Vast majority of granular cell tumors are benign
- Characteristics from various references state that lesions greater than 5 cm in diameter, with increased cellularity, tumor cell necrosis, > 2 mitoses per 10 HPFs, spindled tumor cells, deep location, nuclear pleomorphism and prominent nucleoli are at higher risk of showing malignant behavior; but no findings are pathognomonic of malignancy except vascular invasion or metastasis
- There are clearly documented examples of malignant behavior from typical, small, bland granular cell tumors
- Incompletely excised tumors may recur
Case reports
- 66 year old man with malignant granular cell tumor of the anal perianal region and suprarenal hyperplasia (Indian J Dermatol 2010;55:403)
- 66 year old woman (Int Surg 2014;99:45)
- Anal region: an unusual location of granular cell tumor (Int J Colorectal Dis 2011;26:811)
- Malignant granular cell tumors (Ann Pathol 1999;19:151)
Treatment
- Conservative local excision
Clinical images
Images hosted on other servers:
Solitary cutaneous nodule
Gross description
- Usually firm, poorly circumscribed, pale tan yellow nodule
- Overlying skin may appear thickened
Microscopic (histologic) description
- Identical to granular cell tumors elsewhere
- Sheets, nests, cords or trabeculae of tumor cells
- Most cells are large, oval to round, with prominent granular cytoplasm
- PAS positive, diastase resistant granules are present in from 1/3 to nearly all cases (Fletcher: Pathology and Genetics of Tumours of Soft Tissue and Bone, 3rd Edition, 2006, Fletcher: WHO Classification of Tumours of Soft Tissue and Bone, 4th Edition, 2013)
- Nuclei vary from small, round, and hyperchromatic to those with larger size, more open chromatin and visible nucleoli
- Smaller cells with coarse granules known as interstitial cells or angulate body cells are also present
- Perineural invasion may be seen but is not indicative of malignancy
- A desmoplastic stromal reactive may be seen in older lesions
- The overlying skin may show prominent pseudoepitheliomatous hyperplasia that may mimic squamous cell carcinoma
Microscopic (histologic) images
Images hosted on other servers:
Voluminous cells
Malignant tumor
S100+
NSE+
Positive stains
- dPAS, S100, myelin basic protein, calretinin, inhibin A, CD68
Negative stains
Electron microscopy description
- Rarely employed for diagnosis
- Phagolysosomes with prominent myelin figures
- Interstitial cells contain parallel microtubules, lipids and cytoplasmic processes
Differential diagnosis
- Adult rhabdomyoma
- Fibroxanthoma
- Hibernoma
- Squamous cell carcinoma: from superficial biopsies of pseudoepitheliomatous hyperplasia
