These tumours are a subset of gastrointestinal stromal tumours (GIST) showing ultrastructural features (these features include complex interdigitating cell processes, neurosecretory granules, bulbous synaptic terminals, rudimentary cell junctions, and intermediate filaments) of autonomic nerve differentiation. At a light microscopic level, they may have a spindle cell or epithelioid morphology. They do not differ immunohistochemically from GISTs. The early reports indicated that they behave as malignant tumours, but this view is under revision and they may merely be variants of GIST, with ultrastructural differentiation no longer consider obligatory.
In contrast to GIST, GANT is rather more common in the small intestine (47%) than the stomach (41%), but has been reported form the oesophagus, colon, retroperitoneum, omentum, mesentery and peritoneum. In three cases it has been reported as a component of Carney's triad (intestinal stromal tumour, extra-adrenal paraganglioma and pulmonary chondroma). Three cases have also bee reported in association with type I neurofibromatosis. There is one report of multiple familial GANTs in association with intestinal neuronal dysplasia.
Immunohistochemistry (based on a compilation of the published literature)1:
|
21/21 |
|
|
30/52 (58%) |
|
|
89/96 (93%) |
|
|
NSE |
95/107 (89%) |
|
8/85 (9%) |
|
|
37/100 (37%) |
|
|
42/107 (39%) |
|
|
0/94 |
|
|
1/93 (1%) |
|
|
8/93 (9%) |
|
Prognosis
Of the 76 patients with published outcomes:
62% free from tumour at a mean of 25 months
14% alive with disease at a mean of 28 months
24% died of disease at a mean of 13 months.
There is insufficient data to accurately assess prognostic factors, but tumour size and site seem most important.
|
|
number of cases |
no evidence of disease |
alive with disease |
dead of disease |
|
1.5 to 5.5 cm |
22 |
91% |
0% |
9% |
|
6 to 10 cm |
24 |
71% |
17% |
12% |
|
11 to 15 cm |
12 |
50% |
17% |
33% |
|
16 to 36 cm |
18 |
22% |
28% |
50% |
|
|
number of cases |
no evidence of disease |
alive with disease |
dead of disease |
|
small intestine |
51 |
51% |
17% |
32% |
|
stomach |
44 |
82% |
11% |
7% |
|
all other sites |
13 |
too few cases to assess |
||
References
©SMUHT/PW Bishop