From the Guidelines
Imaging for metastasis in high-grade facial cutaneous squamous cell carcinoma (SCC) is recommended for patients with specific high-risk features, including tumors larger than 2 cm in diameter, depth greater than 6 mm or invasion beyond subcutaneous fat, poorly differentiated histology, perineural invasion, location on high-risk sites, immunosuppression, or recurrent disease. The indications for imaging to detect metastasis in high-grade Squamous Cell Carcinoma (SCC) of the face are based on the presence of high-risk features that increase the likelihood of metastasis. Some key high-risk features that warrant imaging include:
- Tumors larger than 2 cm in diameter
- Depth greater than 6 mm or invasion beyond subcutaneous fat
- Poorly differentiated histology
- Perineural invasion
- Location on high-risk sites, such as the lips or ears
- Immunosuppression
- Recurrent disease The preferred imaging modalities for detecting metastasis in high-grade facial SCC include:
- Contrast-enhanced CT of the head and neck to evaluate regional lymph node involvement
- CT of the chest and abdomen or PET/CT for distant metastasis evaluation in more advanced cases
- MRI, which may be particularly useful when perineural invasion is suspected 1 Imaging should be performed prior to definitive treatment to guide surgical planning and determine the need for adjuvant therapy. Early detection of metastasis significantly impacts treatment decisions and prognosis, as high-grade variants on the face have increased risk due to rich lymphatic drainage and proximity to critical structures. Patients with multiple risk factors should undergo more comprehensive imaging evaluation, as their risk of metastasis increases substantially.
From the Research
Indications for Imaging in High-Grade Squamous Cell Carcinoma (SCC) of the Face
The following are indications for imaging to detect metastasis in high-grade Squamous Cell Carcinoma (SCC) of the face:
- High-risk features associated with sub-clinical metastasis, such as depth of invasion (>2 mm), poor histological differentiation, high-risk anatomic location (face, ear, pre/post auricular, genitalia, hands, and feet), perineural involvement, recurrence, multiple cSCC tumors, and immunosuppression 2
- Detection of perineural spread, bony invasion, nodal metastasis (NM), and distant metastasis in cutaneous squamous cell carcinoma 3
- Evaluation of cervical lymph node metastases in head and neck squamous cell carcinoma with clinically negative neck lymph nodes 4
- Identification of high-risk cSCCs that may require aggressive treatment, including radiologic imaging and sentinel lymph node biopsy 5
Imaging Modalities
The following imaging modalities may be used to detect metastasis in high-grade SCC of the face:
- Magnetic resonance imaging (MRI) for detecting perineural spread 3
- Computed tomography (CT) for detecting bony invasion and nodal metastasis 3, 4
- Positron emission tomography-computed tomography (PET-CT) for detecting cervical lymph node metastases 4
- Ultrasound (US) for detecting nodal metastasis 3, 4
Clinical Considerations
Imaging may change management in up to 33% of cases, highlighting the importance of imaging in high-risk cutaneous squamous cell carcinoma 3. The choice of imaging modality depends on the specific clinical scenario and the suspected location of metastasis 3, 4, 5.