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Should Ki67 immunohistochemistry be performed on all lesions in multifocal small intestinal neuroendocrine tumours?
Author(s) -
Numbere Numbereye,
Huber Aaron R,
Shi Chanjuan,
Cates Justin M M,
Gonzalez Raul S
Publication year - 2019
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1111/his.13771
Subject(s) - medicine , grading (engineering) , lesion , hazard ratio , pathology , immunohistochemistry , confidence interval , lymph node , exact test , proportional hazards model , gastroenterology , radiology , biology , ecology
Aims Well‐differentiated small intestinal neuroendocrine tumours ( SI ‐ NET s) are often multifocal, and this has been suggested to impart worse disease‐free survival. Practice guidelines have not been established for World Health Organisation ( WHO ) grading of multiple primary lesions. Methods and results We identified 68 patients with ileal/jejunal SI ‐ NET for a combined total of 207 primary lesions. Each case was evaluated for patient age and sex; size of all tumours; presence of lymph node metastases, mesenteric tumour deposits or distant metastases; and disease‐specific outcome. Ki67 staining was performed on all 207 primary lesions. The relationship between multifocality and clinicopathological factors was compared using Fisher's exact test. Outcome was tested using Cox proportional hazard regression. Forty‐two patients had unifocal disease, and 26 had multifocal disease (median five lesions, range = 2–32). Most tumours were WHO grade 1 (201 of 207, 97%). Of the five patients with grades 2/3 tumours, three patients had unifocal disease, one patient had two subcentimetre grade 2 lesions (including the largest) and eight subcentimetre grade 1 lesions, and one patient had one 1.6‐cm grade 3 lesion and one subcentimetre grade 1 lesion. There was a positive correlation between tumour size and Ki67 index (coefficient 0.28; 95% confidence interval 0.05–0.52, P = 0.017). There was no significant association between multifocality and nodal metastases, mesenteric tumour deposits, distant metastases or disease‐specific survival. Conclusions In patients with multifocal SI ‐ NET , unless a particular lesion has a high mitotic rate, only staining the largest lesion for Ki67 should serve to grade almost all cases accurately. Multifocality does not appear to significantly impact patient survival.