Evaluation of immunohistochemical expression of novel neuroendocrine marker INSM1 and histological tumor growth pattern in well-differentiated neuroendocrine tumors of the appendix: 15-year single tertiary center experience
Introduction: Well-differentiated neuroendocrine tumors of the appendix (A-WDNET) are the most common neoplasms of the appendix but are rare and incidental. INSM1 is a novel transcription factor marker with high sensitivity and specificity for neuroendocrine differentiation. It may display architect...
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| Format: | Article |
| Language: | English |
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Wolters Kluwer Medknow Publications
2024-04-01
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| Series: | Indian Journal of Pathology and Microbiology |
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| Online Access: | https://journals.lww.com/10.4103/ijpm.ijpm_514_23 |
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| author | Ali Koyuncuer Tolga Canbak Aylin Acar Onur Şahin |
| author_facet | Ali Koyuncuer Tolga Canbak Aylin Acar Onur Şahin |
| author_sort | Ali Koyuncuer |
| collection | DOAJ |
| description | Introduction:
Well-differentiated neuroendocrine tumors of the appendix (A-WDNET) are the most common neoplasms of the appendix but are rare and incidental. INSM1 is a novel transcription factor marker with high sensitivity and specificity for neuroendocrine differentiation. It may display architecturally diverse tumor growth patterns including solid, nest, insular trabecular, and acinar.
Aims:
The aim of this study was to determine the staining expression of INSM1 in A-WDNETs and detail the morphological tumor growth patterns.
Materials and Methods:
INSM1 immunohistochemistry was performed on 35 A-WDNET patients. Tumors were histologically classified according to their growth patterns.
Results:
Thirty-five patients, 60% of whom were male, had a mean age of 30 years at diagnosis and a mean tumor size of 0.9 cm. Eight percent of the tumors invaded the mucosa/submucosa, 34.3% showed invasion into the muscularis propria, 57.1% showed invasion into the subserosa or mesoappendix, LN metastasis was observed in two patients, lymph-vascular invasion in two patients, and perineural invasion in five patients. Ninety-four percent of the tumors were grade 1, the mitotic rate was >2% in two cases, and Ki-67 PI was >3% in two cases. INSM1 was positive in all cases (100%), 1+ 8.6%, 2+ 5.7%, 3+ 17.1%, 4+ 68.6%, weak staining in 11.4%, moderate staining in 22.9%, and strong staining in 67.7%. Type A histological growth pattern was observed in 54.3%, type B in 31.4%, and type C in 14.3% architecturally.
Conclusions:
INSM1 was positive in all A-WDNET morphological patterns and was 100% sensitive. INSM1 IHC can be used as an alternative to traditional neuroendocrine markers or in combination with the diagnosis of neuroendocrine tumors. |
| format | Article |
| id | doaj-art-249d59e163fc41ee9bec7b0a320c0c35 |
| institution | Kabale University |
| issn | 0377-4929 0974-5130 |
| language | English |
| publishDate | 2024-04-01 |
| publisher | Wolters Kluwer Medknow Publications |
| record_format | Article |
| series | Indian Journal of Pathology and Microbiology |
| spelling | doaj-art-249d59e163fc41ee9bec7b0a320c0c352025-02-07T13:56:08ZengWolters Kluwer Medknow PublicationsIndian Journal of Pathology and Microbiology0377-49290974-51302024-04-0167228228810.4103/ijpm.ijpm_514_23Evaluation of immunohistochemical expression of novel neuroendocrine marker INSM1 and histological tumor growth pattern in well-differentiated neuroendocrine tumors of the appendix: 15-year single tertiary center experienceAli KoyuncuerTolga CanbakAylin AcarOnur ŞahinIntroduction: Well-differentiated neuroendocrine tumors of the appendix (A-WDNET) are the most common neoplasms of the appendix but are rare and incidental. INSM1 is a novel transcription factor marker with high sensitivity and specificity for neuroendocrine differentiation. It may display architecturally diverse tumor growth patterns including solid, nest, insular trabecular, and acinar. Aims: The aim of this study was to determine the staining expression of INSM1 in A-WDNETs and detail the morphological tumor growth patterns. Materials and Methods: INSM1 immunohistochemistry was performed on 35 A-WDNET patients. Tumors were histologically classified according to their growth patterns. Results: Thirty-five patients, 60% of whom were male, had a mean age of 30 years at diagnosis and a mean tumor size of 0.9 cm. Eight percent of the tumors invaded the mucosa/submucosa, 34.3% showed invasion into the muscularis propria, 57.1% showed invasion into the subserosa or mesoappendix, LN metastasis was observed in two patients, lymph-vascular invasion in two patients, and perineural invasion in five patients. Ninety-four percent of the tumors were grade 1, the mitotic rate was >2% in two cases, and Ki-67 PI was >3% in two cases. INSM1 was positive in all cases (100%), 1+ 8.6%, 2+ 5.7%, 3+ 17.1%, 4+ 68.6%, weak staining in 11.4%, moderate staining in 22.9%, and strong staining in 67.7%. Type A histological growth pattern was observed in 54.3%, type B in 31.4%, and type C in 14.3% architecturally. Conclusions: INSM1 was positive in all A-WDNET morphological patterns and was 100% sensitive. INSM1 IHC can be used as an alternative to traditional neuroendocrine markers or in combination with the diagnosis of neuroendocrine tumors.https://journals.lww.com/10.4103/ijpm.ijpm_514_23appendicealgradehistomorphologyinsm1neuroendocrine tumors |
| spellingShingle | Ali Koyuncuer Tolga Canbak Aylin Acar Onur Şahin Evaluation of immunohistochemical expression of novel neuroendocrine marker INSM1 and histological tumor growth pattern in well-differentiated neuroendocrine tumors of the appendix: 15-year single tertiary center experience Indian Journal of Pathology and Microbiology appendiceal grade histomorphology insm1 neuroendocrine tumors |
| title | Evaluation of immunohistochemical expression of novel neuroendocrine marker INSM1 and histological tumor growth pattern in well-differentiated neuroendocrine tumors of the appendix: 15-year single tertiary center experience |
| title_full | Evaluation of immunohistochemical expression of novel neuroendocrine marker INSM1 and histological tumor growth pattern in well-differentiated neuroendocrine tumors of the appendix: 15-year single tertiary center experience |
| title_fullStr | Evaluation of immunohistochemical expression of novel neuroendocrine marker INSM1 and histological tumor growth pattern in well-differentiated neuroendocrine tumors of the appendix: 15-year single tertiary center experience |
| title_full_unstemmed | Evaluation of immunohistochemical expression of novel neuroendocrine marker INSM1 and histological tumor growth pattern in well-differentiated neuroendocrine tumors of the appendix: 15-year single tertiary center experience |
| title_short | Evaluation of immunohistochemical expression of novel neuroendocrine marker INSM1 and histological tumor growth pattern in well-differentiated neuroendocrine tumors of the appendix: 15-year single tertiary center experience |
| title_sort | evaluation of immunohistochemical expression of novel neuroendocrine marker insm1 and histological tumor growth pattern in well differentiated neuroendocrine tumors of the appendix 15 year single tertiary center experience |
| topic | appendiceal grade histomorphology insm1 neuroendocrine tumors |
| url | https://journals.lww.com/10.4103/ijpm.ijpm_514_23 |
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