Intraductal papillary mucinous tumour

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Intraductal papillary mucinous tumour, abbreviated IPMT, is an uncommon tumour of the pancreas.

It is also known as intraductal papillary mucinous neoplasm (abbreviated IPMN).

General

  • Morphologically and biologically distinct from ductal adenocarcinoma, mucinous cystic tumour and ductal papillary hyperplasia.
  • Prognosis:
    • Favourable if caught early; not much different than ductal adenocarcinoma if caught late.[1]
    • Dependent what is involved:[2]
      • Main duct (bad prognosis).
      • Branch (good prognosis).


Clinical:

  • Patient usually not jaundiced... as no obstruction.
  • Often diabetes... as pancreas is destroyed.
  • Patients may get a total pancreatectomy - as the disease is often multifocal.

Epidemiology

  • ~1% of all exocrine pancreatic tumours.
  • More common in males.
  • Mean age at presentation 62 years.
  • 60-80% occur in the head of the pancreas.
  • Average size 4 cm.

Classification of IMPT

Commonly classified by the duct involvement:[3]

  1. Main duct type.
    • Commonly associated with invasive carcinoma.
  2. Branch duct type.
    • Less commonly associated with invasive carcinoma.

The oncocytic subtype of IPMT is now known to be genetically separate from other types.[4]

Behaviour
  • Adenoma.
  • Borderline mucinous tumour.
  • Carcinoma.

Notes:

  • Borderline tumours are rare.
  • If intralobular dilated ducts... carcinoma.
  • Any margin with mucin cells in thought to be badness!

Gross

  • May be patchy/multifocal.
  • Multiple cystic spaces.

Microscopic

Features:

  • Pancreatic duct lining cells jut into the duct lumen - papillomatous growth pattern.
  • Cytology:
    • Cell enlargement.
      • Increased mucin production.
    • Nuclear changes:
    • Mitotic activity.

Note:

  • No ovarian type stroma underneath (as seen in mucinous tumours).

DDx:

See also

References

  1. Maire F, Hammel P, Terris B, et al. (November 2002). "Prognosis of malignant intraductal papillary mucinous tumours of the pancreas after surgical resection. Comparison with pancreatic ductal adenocarcinoma". Gut 51 (5): 717–22. PMC 1773420. PMID 12377813. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=12377813.
  2. Baiocchi GL, Portolani N, Missale G, et al. (2010). "Intraductal papillary mucinous neoplasm of the pancreas (IPMN): clinico-pathological correlations and surgical indications". World J Surg Oncol 8: 25. doi:10.1186/1477-7819-8-25. PMC 2858722. PMID 20374620. http://wjso.com/content/8/1/25.
  3. Ikeuchi, N.; Itoi, T.; Sofuni, A.; Itokawa, F.; Tsuchiya, T.; Kurihara, T.; Ishii, K.; Tsuji, S. et al. (Apr 2010). "Prognosis of cancer with branch duct type IPMN of the pancreas.". World J Gastroenterol 16 (15): 1890-5. PMID PMC = 2856831 20397268 PMC = 2856831.
  4. Basturk O, Tan M, Bhanot U, Allen P, Adsay V, Scott SN, Shah R, Berger MF, Askan G, Dikoglu E, Jobanputra V, Wrzeszczynski KO, Sigel C, Iacobuzio-Donahue C, Klimstra DS. (2016). "The oncocytic subtype is genetically distinct from other pancreatic intraductal papillary mucinous neoplasm subtypes". Mod Pathol 29: 1058-69. PMID 27282351.