High-grade appendiceal mucinous neoplasms
Updates to Article Attributes
High-grade appendiceal mucinous neoplasms (HAMN) are rare mucinous tumours of the appendix showing high-grade cytologic atypia, c.fcf. low-grade appendiceal mucinous neoplasms (LAMN). The distinction between both LAMN and HAMN is done on a histologic groundhistological grounds and thosethese tumours basically look the same on imaging. Please, refer to the LAMN article for a detailed conjoined discussion on their imaging findings.
Terminology
Considerable controversy still exists on mucinous neoplasms of the appendix pathologic classification and nomenclature 3. According to a panel of specialist review in 2016, a new nomenclature and classification for the appendiceal mucinous neoplasms based on their histologic type and biologic behaviour has been proposed, which now includes the “high-grade appendiceal mucinous neoplasm”. The HAMN was proposed to include the lesions that have high-grade atypia and thus cannot be grouped as a LAMN, but also do not have the infiltrative invasion to be characterised as an appendiceal mucinous adenocarcinoma 1-2,2.
Pathology
Histologically these tumours show high-grade cytologic atypia associated with at least one of the following 1-2,2:
- loss of the muscularis mucosae
- fibrosis of the submucosa
- rupture of the appendix
- mucin and/or
tumoraltumoural cells outside the appendix
-<p><strong>High-grade appendiceal mucinous neoplasms (HAMN) </strong>are rare <a href="/articles/mucinous-neoplasms-of-the-appendix">mucinous tumours of the appendix</a> showing high-grade cytologic atypia, c.f. <a href="/articles/low-grade-appendiceal-mucinous-neoplasm">low-grade appendiceal mucinous neoplasms (LAMN)</a>. The distinction between both LAMN and HAMN is done on a histologic ground and those tumours basically look the same on imaging. Please, refer to the LAMN article for a detailed conjoined discussion on their imaging findings. </p><h4>Terminology </h4><p>Considerable controversy still exists on mucinous neoplasms of the appendix pathologic classification and nomenclature <sup>3</sup>. According to a panel of specialist review in 2016, a new nomenclature and classification for the appendiceal mucinous neoplasms based on their histologic type and biologic behaviour has been proposed, which now includes the “high-grade appendiceal mucinous neoplasm”. The HAMN was proposed to include the lesions that have high-grade atypia and thus cannot be grouped as a LAMN, but also do not have the infiltrative invasion to be characterised as an appendiceal mucinous adenocarcinoma <sup>1-2</sup>.</p><h4>Pathology</h4><p>Histologically these tumours show high-grade cytologic atypia associated with at least one of the following <sup>1-2</sup>: </p><ul>- +<p><strong>High-grade appendiceal mucinous neoplasms (HAMN) </strong>are rare <a href="/articles/mucinous-neoplasms-of-the-appendix">mucinous tumours of the appendix</a> showing high-grade cytologic atypia, cf. <a href="/articles/low-grade-appendiceal-mucinous-neoplasm">low-grade appendiceal mucinous neoplasms (LAMN)</a>. The distinction between both LAMN and HAMN is done on histological grounds and these tumours look the same on imaging. Please, refer to the LAMN article for a detailed conjoined discussion on their imaging findings. </p><h4>Terminology </h4><p>Considerable controversy still exists on mucinous neoplasms of the appendix pathologic classification and nomenclature <sup>3</sup>. According to a panel of specialist review in 2016, a new nomenclature and classification for the appendiceal mucinous neoplasms based on their histologic type and biologic behaviour has been proposed, which now includes the “high-grade appendiceal mucinous neoplasm”. The HAMN was proposed to include the lesions that have high-grade atypia and thus cannot be grouped as a LAMN, but also do not have the infiltrative invasion to be characterised as an appendiceal mucinous adenocarcinoma <sup>1,2</sup>.</p><h4>Pathology</h4><p>Histologically these tumours show high-grade cytologic atypia associated with at least one of the following <sup>1,2</sup>: </p><ul>
-<li>mucin and/or tumoral cells outside the appendix</li>- +<li>mucin and/or tumoural cells outside the appendix</li>
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