Neuroendocrine neoplasms of the digestive tract: incorporating the 2019 WHO grading schema in the South African context

BACKGROUND

The classification of gastrointestinal (GI) neuroendocrine neoplasms (NENs) has been updated in the WHO classification of tumours of the digestive tract. Mitotic rate and Ki-67 proliferation index are central to the histopathological grading of these tumours. Assessing these variables is not standardised in local practice. This study addresses this deficit in the South African context.

METHODS

This is a retrospective audit of archival material of resection specimens of GI NENs (excluding appendix) at Groote Schuur Hospital from 2004 to 2017. We performed a mitotic count and immunohistochemistry for Ki-67 to reclassify tumours according to the 2019 WHO criteria.

RESULTS

Thirty-five resection specimens were examined. These represented stomach (n = 5), jejunoileum (n = 17), colon (n = 7) and rectum (n = 6). The mean age at the time of resection was 56 years (range 32-72). Twenty-one cases (60%) were women and 14 (40%) were men. The majority (24/35) of tumours were classified as grade 1 well-differentiated neuroendocrine tumours (WD NETs), 8/35 were classified as grade 2 WD NETs and 3/35 were classified as small cell poorly differentiated neuroendocrine carcinomas (PD NECs). Re-classification resulted in 7/35 (20%) changes in tumour grade (4 upgraded, 3 downgraded). In most instances (7/8), the Ki-67 proliferation index was the determining factor in assigning tumour grade.

CONCLUSION

This study has increased awareness of the recently updated WHO classification system. We conclude that an objective and systematic approach to counting of mitoses and determination of the Ki-67 proliferation index is recommended in routine practice.

Liver resection for non-cirrhotic hepatocellular carcinoma in South African patients

BACKGROUND

We describe the clinicopathologic features and outcome of South African patients who have undergone hepatic resection for hepatocellular carcinoma (HCC) arising in a non-cirrhotic liver.

METHODS

We utilised the prospective liver resection database in the Surgical Gastroenterology Unit at Groote Schuur Hospital, Cape Town, to identify all patients who underwent surgery for HCC with non-cirrhotic liver parenchyma between 1990 and 2008.

RESULTS

Twenty-two patients (10 men, 12 women, 3 black, 19 white, median age 47 years, range 21-79 years) underwent surgery for non-cirrhotic HCC. Sixteen patients had non-fibrolamellar HCC (Group 1); 6 patients had fibrolamellar HCC (Group 2). Group 1 had a median age of 55 years, and 6 (38%) were men; group 2 had a median age of 21 years, and 5 (83%) were men. Most patients had a solitary tumour at diagnosis; median largest tumour diameters in Groups 1 and 2 were 10 cm (range 4-21) and 12 cm (range 4-17), respectively. Patients in Group 1 underwent extended right hepatectomy (N=3), right hepatectomy (N=3), left hepatectomy (N=3), partial hepatectomy (N=7), cholecystectomy (N=6), and appendicectomy (N=1). Patients in Group 2 underwent extended right hepatectomy (N=1), right hepatectomy (N=1), left hepatectomy (N=2), segmentectomy (N=2), and portal lymphadenectomy (N=3). Recurrence rates in Groups 1, 2, and overall were 81%, 100% and 86%, respectively. Median overall survival was 46 months, with 1-, 3-, and 5-year survival rates of 95%, 59% and 45%, respectively. In Group 1, median survival was 39 months, with 1-, 3-, and 5-year survival rates of 100%, 56% and 38% respectively. In Group 2, median survival was 61 months, with 1-, 3-, and 5-year survival rates of 83%, 67% and 67%, respectively.

CONCLUSION

Despite aggressive surgical resection, HCC arising in normal liver parenchyma has a high recurrence rate and an ultimately poor outcome. This finding is similar to both the recent international experience of non-cirrhotic HCC and local experience of fibrolamellar HCC.