Granular cell tumour

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The granular cell tumour is a rare histomorphologically distinctive neoplasm found at many sites. The classic location is the head and neck.

Granular cell tumour
Diagnosis in short

Granular cell tumour. H&E stain.

LM cells with abundant eosinophilic granular cytoplasm (granules ~ 1-3 micrometers, poorly demarcated on LM), +/-pseudoepitheliomatous hyperplasia
LM DDx squamous cell carcinoma, oncocytoma, adjacent ulcer, xanthoma, melanocytic nevus with neurotization
Stains PAS +ve
IHC S-100 +ve, CD68 +ve (cytoplasmic), vimentin +ve (membranous), calretinin +ve (usually)
EM abundant lysosomes
Gross yellow nodule
Site typically head and neck - other sites: breast, skin, tongue, esophagus + more

Syndromes LEOPARD syndrome

Prevalence rare
Prognosis usu. benign, may be malignant

General

  • Rare.
  • Usually benign.
  • May seen in the context of LEOPARD syndrome and a mutation in the PTPN11 gene.[1]
    • PTPN11 = protein-tyrosine phosphatase non-receptor type 11.[2]
  • May mimic (well-differentiated) squamous cell carcinoma - histopathologically.
    • There is a well-described phenomenon called pseudoepitheliomatous hyperplasia.[3]

Aside:

Sites

May be seen in any number of sites:

Gross

  • Yellow nodule.

DDx of yellow nodule:

  • Granular cell tumour.
  • Lipoma.
  • Xanthoma.

Microscopic

Features:

  • Cells with abundant eosinophilic granular cytoplasm - key feature.
    • Granules (represent abundant lysosomes[4]):
      • Size: 1-3 micrometers.
      • Poorly demarcated (on light microscopy).
  • Nested architecture.
  • +/-Pseudoepitheliomatous hyperplasia.

DDx:

Special stains

  • PAS +ve.

IHC

Features:[5]

  • S100 +ve.
  • CD68 +ve (cytoplasmic).
  • Vimentin +ve (membranous).
  • Calretinin +ve (90-95%).[6]

Images

EM

  • Abundant lysosomes.[4]
    • Round structures with variable (electron) density.

Images:

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SKIN LESION, NECK, EXCISION:
- GRANULAR CELL TUMOUR.
- MILD SOLAR ELASTOSIS.

COMMENT:
The lesional cells stain as follows:
POSITIVE: S-100, CD68, vimentin, calretinin.
NEGATIVE: HMB-45.

Micro

The sections show skin with nests of cells in the mid dermis, extending to the subcutis. The cells that make up the nests have an abundant granular grey cytoplasm, and round regular nuclei without obvious nucleoli. No mitotic activity is readily apparent. The lesional cells focally wrap around nerve. The superficial dermis has mild solar elastosis. The lesion is completely excised in the plane of section.

See also

References

  1. Schrader, KA.; Nelson, TN.; De Luca, A.; Huntsman, DG.; McGillivray, BC. (Feb 2009). "Multiple granular cell tumors are an associated feature of LEOPARD syndrome caused by mutation in PTPN11.". Clin Genet 75 (2): 185-9. doi:10.1111/j.1399-0004.2008.01100.x. PMID 19054014.
  2. Online 'Mendelian Inheritance in Man' (OMIM) 176876
  3. Abu-Eid R, Landini G (March 2006). "Morphometrical differences between pseudoepitheliomatous hyperplasia in granular cell tumours and squamous cell carcinomas". Histopathology 48 (4): 407–16. doi:10.1111/j.1365-2559.2006.02350.x. PMID 16487362.
  4. 4.0 4.1 Ordóñez, NG. (Jul 1999). "Granular cell tumor: a review and update.". Adv Anat Pathol 6 (4): 186-203. PMID 10410172.
  5. Rekhi, B.; Jambhekar, NA. (Jun 2010). "Morphologic spectrum, immunohistochemical analysis, and clinical features of a series of granular cell tumors of soft tissues: a study from a tertiary referral cancer center.". Ann Diagn Pathol 14 (3): 162-7. doi:10.1016/j.anndiagpath.2010.01.005. PMID 20471560.
  6. Fine, SW.; Li, M. (Feb 2003). "Expression of calretinin and the alpha-subunit of inhibin in granular cell tumors.". Am J Clin Pathol 119 (2): 259-64. doi:10.1309/GRH4-JWX6-J9J7-QQTA. PMID 12579997.