Can squamous cell carcinoma metastasize to the liver as a cystic lesion and to the lumbar spine (L1) as a solid mass?

Metastatic Patterns of Squamous Cell Carcinoma

Yes, squamous cell carcinoma can metastasize to both the liver and bone (including the lumbar spine), though liver metastases presenting as cystic lesions are extremely uncommon and should prompt consideration of alternative diagnoses or atypical presentations.

Typical Metastatic Sites for Squamous Cell Carcinoma

Squamous cell carcinoma most commonly metastasizes to:

• Regional lymph nodes (most common initial metastatic site) 1
• Lungs (most common distant organ) 1
• Liver (documented but less common than lungs) 1
• Bone (including spine) 1
• Extrapelvic lymph nodes 1

Liver Metastases: Solid vs Cystic Presentation

The critical issue is that liver metastases from squamous cell carcinoma typically present as solid masses, not cystic lesions 1. The evidence shows:

• Anal squamous cell carcinoma metastasizes to liver as one of the most common distant sites, but these are described as solid metastases 1
• Head and neck squamous cell carcinoma can produce liver metastases, but cystic presentation is not the typical pattern 1
• When liver lesions appear cystic on imaging, alternative diagnoses must be strongly considered, including benign cysts, hemangiomas, or other pathology 1

Bone/Spine Metastases: Expected Presentation

Bone metastases from squamous cell carcinoma typically present as solid masses, which matches your L1 spine finding 1. The evidence demonstrates:

• Skeletal metastases to vertebrae are well-documented in squamous cell carcinoma 1
• These metastases can involve soft tissue extension and appear as masses on imaging 1
• Bone involvement increases with advanced stage disease and recurrent disease 1

Clinical Implications and Diagnostic Approach

Given the atypical cystic appearance of the liver lesion, you must obtain tissue confirmation before assuming this represents metastatic squamous cell carcinoma 1. The recommended approach includes:

• Biopsy of the liver lesion to confirm squamous cell carcinoma histology, as cystic liver lesions have broad differential diagnosis including benign entities 1
• Advanced imaging with MRI may help characterize the liver lesion more definitively, particularly using diffusion-weighted imaging and contrast enhancement patterns 1
• Biopsy of the spine lesion if not already performed, to confirm metastatic squamous cell carcinoma 1
• PET/CT imaging to assess for additional metastatic sites, as this modality has high sensitivity (100% in some studies) and specificity (99%) for detecting distant metastases 1

Primary Tumor Considerations

The primary site of squamous cell carcinoma influences metastatic patterns:

• Cutaneous squamous cell carcinoma has approximately 4% overall metastatic risk, but this increases to 8-12% in immunosuppressed patients 1
• Head and neck squamous cell carcinoma has higher metastatic potential and more commonly involves distant sites 1, 2
• Anal squamous cell carcinoma specifically lists liver as a common metastatic site (along with lung and extrapelvic lymph nodes) 1

Critical Pitfalls to Avoid

• Do not assume a cystic liver lesion is metastatic disease without histologic confirmation, as this is an atypical presentation that could represent benign pathology, infection, or other malignancy 1
• Do not delay multidisciplinary consultation involving medical oncology, radiation oncology, and surgical oncology, as metastatic squamous cell carcinoma requires coordinated treatment planning 1, 3
• Do not overlook the immunosuppression status of the patient, as transplant recipients and other immunosuppressed individuals have 2-3 times higher metastatic risk and more aggressive disease behavior 1, 4

Treatment Implications for Stage IV Disease

If both lesions are confirmed as metastatic squamous cell carcinoma, treatment options include:

• First-line systemic therapy with PD-1 inhibitors (pembrolizumab or cemiplimab) for cutaneous squamous cell carcinoma 3
• Carboplatin plus paclitaxel as preferred first-line regimen for metastatic anal squamous cell carcinoma, showing median overall survival of 20 months 1
• Consideration of palliative radiation to the spine lesion for pain control and prevention of pathologic fracture or spinal cord compression 1
• Possible resection or ablation of liver metastases in highly selected cases, though this is not standard practice and should only be considered within clinical trials 1