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LST-G, LST-NG

Saturday 25 September 2010, Branislav Kunčak, M. D.

Laterally spreading tumor of the colon (LST)

  • Nonpolypoid neoplastic lesions of the colon and rectum larger than 10mm in diameter are called laterally spreading tumors (LST)
  • LST are further subdivided into two sutypes based on endoscopic appearance: granular and non-granular type of LST
  • Granular-type of LST (LST-G): flat lesion with granular (nodular) surface; risk of submucosal invasion is associated with presence of large nodulum
  • Non-granular type of LST (LST-NG): flat lesion with smooth surface and absence of granulonodular structures; risk of submucosal (sm) invasion increases with size of the lesion. Invasive pit pattern and presence of sclerous wall change are also associated with higher risk of sm invasion. Risk of sm invasion is in general higher compared to LST-G.
  • Treatment strategy:

- LST-G: EMR, piecemeal EMR (pEMR) of larger lesions. Area with large nodule should be resected first

- LST-NG: en block resection is recommended. Lesions up to 20mm in diameter can be resected by EMR. Larger lesions and lesions with suspected sm invasion should be resected by ESD (endoscopic submucosal disection) or surgery should be considered.

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Fig. 1

LST-G

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Fig. 2

LST-G (chromoscopy- indigocarmine)

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Fig. 3

Adenomatous pit pattern

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Fig. 4

LST-NG

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Fig. 5

LST-NG (chromoscopy- indigocarmine)

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Fig. 6

Size of the lesion can be estimated according to biopsy forceps

Keywords: laterally spreading tumor of the colon, LST, granular-type of LST, LST-G, non-granular type of LST, LST-NG