Carcinoma ex pleomorphic adenoma
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Carcinoma ex pleomorphic adenoma is the most common of three malignant mixed tumours of salivary glands, and are thought to arise from pre-existing pleomorphic adenomas (or benign mixed tumours) 1.
Epidemiology
These tumours usually occur in older patients (6th to 8th decade), who have had a pleomorphic adenoma in situ for many years (typically 10 - 15-15 years) 1.
Clinical presentation
Patients will describe having had a stable parotid mass for many years, before experiencing rapid growth, often associated with painful facial nerve palsy due to tumour infiltration 1.
Radiographic features
As these tumours are aggressive and infiltrating, they present as irregular masses extending into the gland parenchyma and beyond.
MRI
- T1: heterogeneous signal due to haemorrhage, necrosis and calcification 1
- T2: heterogeneous but generally low signal
-
ADC: low values
(c.f(compared to pleomorphic adenomas which typically have elevated values)
For staging see malignant salivary tumour staging.
Treatment and prognosis
These tumours have a high rate of metastasis at the time of diagnosis (25 - 76-76%) typically to brain, bone, lungs and of course local lymph nodes 2.
Differential diagnosis
The differential is essentially that of other malignant salivary gland tumours including:
-<p><strong>Carcinoma ex pleomorphic adenoma</strong> is the most common of three <a href="/articles/malignant-mixed-tumours-of-salivary-glands" title="malignant mixed tumours of salivary glands">malignant mixed tumours of salivary glands</a>, and are thought to arise from pre-existing <a href="/articles/pleomorphic_adenoma" title="Pleomorphic adenoma">pleomorphic adenomas</a> (or benign mixed tumours) <sup>1</sup>. </p><h4>Epidemiology</h4><p>These tumours usually occur in older patients (6<sup>th</sup> to 8<sup>th</sup> decade), who have had a pleomorphic adenoma in situ for many years (typically 10 - 15 years) <sup>1</sup>. </p><h4>Clinical presentation</h4><p>Patients will describe having had a stable parotid mass for many years, before experiencing rapid growth, often associated with painful facial nerve palsy due to tumour infiltration <sup>1</sup>. </p><h4>Radiographic features</h4><p>As these tumours are aggressive and infiltrating, they present as irregular masses extending into the gland parenchyma and beyond. </p><h5>MRI</h5><ul><li><strong>T1</strong> : heterogeneous signal due to haemorrhage, necrosis and calcification <sup>1</sup></li><li><strong>T2</strong> : heterogeneous but generally low signal</li><li><strong>ADC</strong> : low values (c.f to pleomorphic adenomas which typically have elevated values)</li></ul><p>For staging see <a href="/articles/staging-of-malignant-salivary-gland-tumours" title="Malignant salivary gland tumour staging">malignant salivary tumour staging</a>. </p><h4>Treatment and prognosis</h4><p>These tumours have a high rate of metastasis at the time of diagnosis (25 - 76%) typically to brain, bone, lungs and of course local lymph nodes <sup>2</sup>. </p><h4>Differential diagnosis</h4><p>The differential is essentially that of other malignant <a href="/articles/salivary_gland_tumours" title="Salivary gland tumours">salivary gland tumours</a> including: </p><ul><li><a href="/articles/mucoepidermoid-carcinoma-of-salivary-glands" title="Mucoepidermoid carcinoma">mucoepidermoid carcinoma</a></li><li><a href="/articles/adenoid-cystic-carcinoma" title="adenoid cystic carcinoma">adenoid cystic carcinoma</a></li><li><a href="/articles/myoepithelioma" title="Myoepithelioma">myoepithelioma</a> </li><li><a href="/articles/parotid-adenocarcinoma" title="parotid adenocarcinoma ">parotid adenocarcinoma </a>(not otherwise specified)</li><li><a href="/articles/acinic-cell-carcinoma-of-salivary-glands" title="acinic cell carcinoma of salivary glands">acinic cell carcinoma of salivary glands</a></li><li><a href="/articles/squamous-cell-carcinoma-of-salivary-glands" title="squamous cell carcinoma of salivary glands">squamous cell carcinoma  of salivary glands</a></li><li><a href="/articles/intraparotid-metastasis" title="intraparotid metastasis">intraparotid metastasis</a></li></ul>- +<p><strong>Carcinoma ex pleomorphic adenoma</strong> is the most common of three <a href="/articles/malignant-mixed-tumours-of-salivary-glands">malignant mixed tumours of salivary glands</a>, and are thought to arise from pre-existing <a href="/articles/pleomorphic-adenoma">pleomorphic adenomas</a> (or benign mixed tumours) <sup>1</sup>.</p><h4>Epidemiology</h4><p>These tumours usually occur in older patients (6<sup>th</sup> to 8<sup>th</sup> decade), who have had a pleomorphic adenoma <em>in situ </em>for many years (typically 10-15 years) <sup>1</sup>.</p><h4>Clinical presentation</h4><p>Patients will describe having had a stable parotid mass for many years, before experiencing rapid growth, often associated with painful facial nerve palsy due to tumour infiltration <sup>1</sup>.</p><h4>Radiographic features</h4><p>As these tumours are aggressive and infiltrating, they present as irregular masses extending into the gland parenchyma and beyond.</p><h5>MRI</h5><ul>
- +<li>
- +<strong>T1</strong>: heterogeneous signal due to haemorrhage, necrosis and calcification <sup>1</sup>
- +</li>
- +<li>
- +<strong>T2</strong>: heterogeneous but generally low signal</li>
- +<li>
- +<strong>ADC</strong>: low values (compared to pleomorphic adenomas which typically have elevated values)</li>
- +</ul><p>For staging see <a href="/articles/staging-of-malignant-salivary-gland-tumours">malignant salivary tumour staging</a>.</p><h4>Treatment and prognosis</h4><p>These tumours have a high rate of metastasis at the time of diagnosis (25-76%) typically to brain, bone, lungs and of course local lymph nodes <sup>2</sup>.</p><h4>Differential diagnosis</h4><p>The differential is essentially that of other malignant <a href="/articles/salivary-gland-tumours">salivary gland tumours</a> including:</p><ul>
- +<li><a href="/articles/mucoepidermoid-carcinoma-of-salivary-glands">mucoepidermoid carcinoma</a></li>
- +<li><a href="/articles/adenoid-cystic-carcinoma">adenoid cystic carcinoma</a></li>
- +<li><a href="/articles/myoepithelioma">myoepithelioma</a></li>
- +<li>
- +<a href="/articles/parotid-adenocarcinoma">parotid adenocarcinoma </a>(not otherwise specified)</li>
- +<li><a href="/articles/acinic-cell-carcinoma-of-salivary-glands">acinic cell carcinoma of salivary glands</a></li>
- +<li><a href="/articles/squamous-cell-carcinoma-of-salivary-glands">squamous cell carcinoma of salivary glands</a></li>
- +<li><a href="/articles/intraparotid-metastasis">intraparotid metastasis</a></li>
- +</ul>
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