Mucous Neck Cells
This 42 year old male patient had a gastroscopy 3 months previously which showed a peptic ulcer.  Biopsy was negative for H. pylori but there was evidence of some active inflammation.  The patient was treated with eradication therapy.  A followup gastroscopy is normal  in appearance with no evidence of ulceration.  A random biopsy shows a marked increase in numbers of prominent mucous neck cells.  Acid mucin positivity is identified with mucicarmine and alcian blue at pH 2.5.  Neutral mucins are also seen to be present with a positive PAS stain.  CEA stains are negative.  I am now paying more attention to these prominent signet ring like mucous neck cells in other patients but they are usually seen in smaller numbers.  They are usually positive for acid mucin.  This has made me less concerned for this patient. The textbooks say the normal stomach should only have neutral mucins.  Acid mucins may be seen in intestinal metaplasia and in signet ring cells.  I have been unable to find a satisfactory reference for the formation of acid mucins in other situations in humans.  A study in mice is quoted below which identified acid mucin formation in association with elevated gastrin levels (Konda et al).

I was  obviously concerned about the possibility of signet ring carcinoma in situ in this patient.  In view of the normal endoscopy, negative family history, lack of significant atypia and the presence of similar alcian blue positive cells in other patients I would be happy with a rescope and additional biopsies of any suspicious areas (see followup below).  Assuming there is no evidence of malignancy I will assume the changes are reactive until I can prove otherwise.  It would be interesting to measure his serum gastrin level.

Comparison with a known signet ring carcinoma with adjacent signet ring carcinoma in situ has been provided by Gerard Abadjian from last year.  I am not surprised that signet ring carcinomas are felt to originate from mucous neck cells after having viewed the changes seen in our patient.


 

Authors
  Konda Y.  Kamimura H.  Yokota H.  Hayashi N.  Sugano K.  Takeuchi T.
Title
  Gastrin stimulates the growth of gastric pit with less-differentiated
  features.
Source
  American Journal of Physiology.  277(4 Pt 1):G773-84, 1999 Oct.
Abstract
  Gastrin stimulates the growth of gastric mucosa by increasing mostly its
  glandular region but is not known to induce the growth of a pit region
  where its major constituent cells, gastric surface mucous (GSM) cells,
  turn over rapidly. To investigate the effect of gastrin on GSM cells, we
  generated hypergastrinemic mice by expressing a human gastrin transgene.
  We obtained a hypergastrinemic mouse line whose average serum gastrin
  level is 671 +/- 252 pg/ml (normal level <150 pg/ml). Gastrin-positive
  cells were found in the fundic mucosa. The gastric mucosa exhibited
  hypertrophic growth, which was characterized by an elongated pit with an
  active proliferative zone, but the glandular region containing parietal
  cells was normal or reduced in size. The GSM cells contained fewer mucous
  granules than those of control littermates and lost reactivity to the GSM
  cell-specific cholera toxin beta-subunit lectin. GSM cells along the
  foveolar region and many mucous neck cells became Alcian blue positive,
  suggesting the appearance of sialomucin in these cells. We suggest that
  gastrin stimulates the growth of the proliferative zone of gastric glands,
  which results in the elongation of the pit region whose GSM cells exhibit
  less-differentiated features.

Followup
All those who responded felt the changes were metaplastic.  Vann Schaffner told us that the late Roger Haggitt reviewed a similar case and came to the same conclusion.  Our patient went for repeat gastroscopy with multiple biopsies which showed the same changes in body
mucosa.  There was no evidence of invasion or atypia.  For what its worth I have since found a textbook reference in the Fenoglio
CD-ROM which states that the mucous neck cells in the normal stomach "sometimes produce small amounts of sialomucins and sulfomucins" but is no more specific than that and uses the following references.

Suganuma T, Katsuyama T, Tsukahara M, et al: Comparative histochemical study
of alimentary tracts with special reference to the mucous neck cells of the
stomach. Am J Anat 161:219, 1981.

Filipe MI: Mucins in the gastro-intestinal epithelium. A review. Invest Cell
Pathol 2:195, 1979.

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