Traditional serrated adenoma

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Traditional serrated adenoma, abbreviated TSA, are a rare type of gastrointestinal polyp.

Traditional serrated adenoma
Diagnosis in short

LM ectopic crypt foci (ECF), serrated, eosinophilic cytoplasm, villous-like architecture, "pine cone, fernlike, stellate pit pattern"
Subtypes With and without high grade dysplasia, mixed with other types of polyps
LM DDx villous adenoma, hyperplastic polyp, sessile serrated adenoma
IHC CK20 in the eosinophilic cells, absent in ECF; Ki67 (MIB1) stains ECF and absent in eosinophilic cells, MUC2+, MUC5CA+, MUC6-; In areas of dysplasia TP53+, nuclear B-catenin+; p16+ in late dysplasia
Molecular BRAF & KRAS
Site colon - usu. left side / gastrointestinal polyps

Prevalence very rare
Prognosis benign (pre-malignant)
Clin. DDx other GI polyps
Treatment polypectomy, q3years surveillance colonoscopy

Before the sessile serrated adenomas were recognized, these lesions were known as serrated adenomas.[1]

General

  • Very rare.
  • Pre-malignant.[2]

Gross

Microscopic

Features:[3]

  • Serrated - essential.
  • Eosinophilic cytoplasm - key feature.
  • Nuclear atypia as in tubular adenoma.
    • Nuclear hyperchromasia, enlargement and pseudostratification.
  • Villous-like architecture.
  • Ectopic crypt foci (ECF) - short crypts oriented perpendicular to the main crypt, do not reach muscularis mucosae.[4]

Note:

  • ‡ECF considered pathognomonic for TSA - but seen in other entities.[5]

DDx:[6]

Images

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Polyp, Sigmoid Colon, Polypectomy:
- Traditional serrated adenoma.
-- NEGATIVE for high-grade dysplasia.

Block letters

POLYP, SIGMOID COLON, POLYPECTOMY:
- TRADITIONAL SERRATED ADENOMA.
-- NEGATIVE FOR HIGH-GRADE DYSPLASIA.

Micro

Nonvilliform TSA

This polyp has cytologic dysplasia and serrations at the surface; however, it does not have a villiform architecture. The surface epithelium has eosinophilic cytoplasm. Overall, the morphology is most in keeping with a traditional serrated adenoma.

See also

References

  1. Noffsinger, AE.; Hart, J. (Jul 2010). "Serrated adenoma: a distinct form of non-polypoid colorectal neoplasia?". Gastrointest Endosc Clin N Am 20 (3): 543-63. doi:10.1016/j.giec.2010.03.012. PMID 20656251.
  2. Rosty, C.; Hewett, DG.; Brown, IS.; Leggett, BA.; Whitehall, VL. (Mar 2013). "Serrated polyps of the large intestine: current understanding of diagnosis, pathogenesis, and clinical management.". J Gastroenterol 48 (3): 287-302. doi:10.1007/s00535-012-0720-y. PMID 23208018.
  3. Li SC, Burgart L (March 2007). "Histopathology of serrated adenoma, its variants, and differentiation from conventional adenomatous and hyperplastic polyps". Arch. Pathol. Lab. Med. 131 (3): 440-5. PMID 17516746. http://journals.allenpress.com/jrnlserv/?request=get-abstract&issn=0003-9985&volume=131&page=440.
  4. URL: http://surgpathcriteria.stanford.edu/gitumors/traditional-serrated-adenoma/printable.html. Accessed on: 5 June 2017.
  5. Väyrynen, SA.; Väyrynen, JP.; Klintrup, K.; Mäkelä, J.; Tuomisto, A.; Mäkinen, MJ. (Dec 2016). "Ectopic crypt foci in conventional and serrated colorectal polyps.". J Clin Pathol 69 (12): 1063-1069. doi:10.1136/jclinpath-2015-203593. PMID 27281826.
  6. URL: http://surgpathcriteria.stanford.edu/gitumors/traditional-serrated-adenoma/differential-diagnosis.html. Accessed on: 28 May 2015.