Thomas sign


Silver, aluminium or metallic coloured stools. Caused by the combination of cholestatic (acholic) pale stools secondary to CBD obstruction and the black-tar colour malaena.

Thomas’s silver stool sign is a rare but specific sign for carcinoma involving the ampulla of Vater.

History of the silver stool

1955Sir William Heneage Ogilvie (1887-1971) reported on two cases of ampullary cancer presenting with silver stools. A 46 year old female presenting with obstructive jaundice and weight loss; and a 78 year old male presenting with anaemia, and jaundice post blood transfusion. In both cases the stool sample were analysed by Dr Antony Michael Thomas (1913-1971), who made the tentative connection between the stool colour, consistency and carcinoma.

Dr. A. M. Thomas, pathologist to the Royal Masonic Hospital, has pointed out that in cancer involving the ampulla of Vater the patient sometimes passes “silver stools” – that is, motions having the colour of oxidized silver or aluminium paint. The silver or grey stool is a combination of the white stool of obstructive jaundice and the black stool of melaena.

So far as I am aware the silver stool has never been described before. I bring the sign to the attention of surgeons because Dr. Thomas has not yet reported it himself and, being a pathologist, he is likely to report it in a journal read only by his brother pathologists.

Ogilvie 1955

1960 – The first textbook publication by Hamilton Bailey in the 13th edition of Demonstrations of Physical Signs in Clinical Surgery – however, the term appears to have been dropped from all subsequent editions

…the silver stool is the color of aluminum paint and is due to a mixture of the black (melaena) stool with white fatty stool. In jaundiced patients of mature age the silver stool is fairly characteristic of carcinoma of the ampulla of Vater. The silver stool occurs also in tropical sprue and in children recovering from diarrhea when sulphonamides have been administered.

Hamilton Bailey. 1960:42

1963 – SC Simmons published the case of a 29-year-old woman with recurrent jaundice of pregnancy who passed silver stools on two occasions but who recovered completely.

Thomas’s sign does not seem to have been reported before in obstetric hepatosis. In this case it was attributed to the administration of oral iron in association with the stool of obstructive jaundice. Such stools have since been reproduced by giving oral iron to jaundiced patients.

Simmons, 1963

1968 – GL Bolt corresponded with the BMJ on the fourth recorded case report in the British literature:

This week, in a middle-aged man with symptoms suggesting duodenal ulceration, but with marked weight loss, the appearance of jaundice and the observation of a metallic looking stool prompted me to refer him to my surgical colleague. At laparotomy, carcinoma of the head of the pancreas was discovered.

Bolt 1968

1979 – Ong and Pintauro published the case of a 78 year old female with jaundice, weight loss, dehydration and grey-silver metallic stools.

Thomas sign Silver Stool 1979 JAMA
Ong YY, JAMA 1979

A stool specimen was sent to the laboratory with a request for a heavy metal screen. On examination, a metallic silver sheen was noted. The test for occult blood was positive, and the test for bile was negative.

Ong, Pintauro 1979

Exploratory laparotomy of the 11th hospital day disclosed a lima-bean-sized obstructing adenocarcinoma of the ampulla of Vater.

More cases

Below a series of links to clinical cases and discussions on the silver stool and ampulla of Vater carcinoma in the literature

Example 1
Thomas sign Silver Stool 2016 BMJ
A woman presented with weight loss, jaundice, and silver coloured stools. CA19-9 was raised. CT scan suggested pancreatobiliary tumour.
Waqar et al. BMJ 2016

Example 2
Thomas sign Silver Stool 2012 BJS
Tang TY et al. BJS 2012

Example 3
Thomas sign Silver Stool 2013 AGA
A. Silver stool.
B. CT revealed contrast remaining in lumen of second stage of duodenum (long arrow), and a mass adjacent to and invading the second stage of the duodenum obstructing the distal common bile duct (CBD) at the ampulla of Vater (Figure B, arrowhead).
Wyse J, Drudi L. Gastroenterology. 2013

Associated Persons
  • Sir William Heneage Ogilvie (1887-1971)
  • Dr Antony Michael Thomas (October 3, 1913-1971) – MRCS, LRCP (1938); MA, MB BCh (Camb) 1939; Pathol EMS; pathologist to the Royal Masonic Hospital, Musgrove Park Hospital;

Alternative names
  • Thomas’ sign, Thomas’s sign
  • Silver stool sign


Historical references

Eponymous term review



the names behind the name

Doctor in Australia. Keen interest in internal medicine, medical education, and medical history.

BA MA (Oxon) MBChB (Edin) FACEM FFSEM. Emergency physician, Sir Charles Gairdner Hospital.  Passion for rugby; medical history; medical education; and asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | Twitter |

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