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.

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:

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.