22512              CARCINOMA OF THE ASCENDING COLON AND MELANOSIS COLI

The patient was a woman aged 59.  She had polyuria since early childhood and at the age of 54 a diagnosis of diabetes insipidus was established, which was treated with pitressin and subsequently with lysine vasopressine.  In the 6 months before admission she had gained 19 kilos in weight, there were fat pads around the neck, increased skin pigmentation and increasing hirsuitism.  The BP was 210/95. She had a definite Cushingoid appearance.  During detailed investigations a carcinoma of the ascending colon was found by barium enema but she developed a Listeria monocytogenes septicaemia with meningitis.  Antibiotics were given but she died after a month in hospital.

The specimen consists of 10 cms of the terminal ileum and the proximal 20 cms of the colon including the caecum.  There is a fungating encircling carcinoma in the ascending colon 6 cms above the ileo-caecal valve.  The tumour is pale and firm and its surface is somewhat ragged.  The colonic mucosa shows intense melanosis coli but the tumour itself is not pigmented.  A small sessile polyp 5 cms above the carcinoma is also not pigmented.  Regional lymph nodes were invaded by tumour and there were large metastases in the liver.  Section of the hypothalamus showed that the supra-optic nuclei were deficient in neurones compared to a control.  The cell density appeared about 20% of normal.  The endocrinologist presumed that the Cushing's syndrome was due to ectopic hormone production from the colonic tumour.