Lymphovascular invasion
LVI; angiolymphatic invasion; lymphatic / vascular invasion
Lymphovascular invasion is the histological identification of tumour cells within the lumina of dermal or subcutaneous lymphatics or blood vessels. It is an independent adverse prognostic feature in melanoma, cutaneous squamous cell carcinoma, Merkel cell carcinoma and many sarcomas, increasing the risk of nodal and distant metastasis. In melanoma, LVI is one of the NG14 §1.4.3 adverse features that supports SLNB discussion for melanomas 0.8–1.0 mm thick. In cSCC, LVI is recorded in the RCPath dataset and contributes to risk stratification (though not formally to BWH or AJCC T-staging). Detection benefits from immunohistochemistry — D2-40 for lymphatics, ERG / CD31 / CD34 for blood vessels.
Definition
- Tumour cells within the lumen of a dermal or subcutaneous lymphatic or blood vessel, identified on H&E or confirmed by immunohistochemistry.
- Lymphatic invasion — tumour within a thin-walled endothelial-lined channel without a muscular wall.
- Vascular invasion — tumour within an artery or vein with a muscular wall; less common, generally more adverse than lymphatic.
- Reported as present / absent in the pathology dataset.
Immunohistochemical confirmation
- D2-40 (podoplanin) — selective for lymphatic endothelium.
- CD31, ERG, CD34 — pan-endothelial markers (lymphatic and vascular).
- Adjunct IHC distinguishes true vessel involvement from artefactual displacement of tumour cells into spaces during sectioning.
- Difficult cases — specialist dermatopathology review.
Role in melanoma (NG14)
- NG14 §1.4.3–1.4.4 — consider SLNB for Breslow 0.8–1.0 mm melanoma if ulceration, mitotic index ≥ 2 or lymphovascular invasion is present, and for Breslow > 1.0 mm after discussion of benefits and risks.
- LVI is one of the adverse features that supports SLNB discussion in borderline-thickness disease.
- Increases risk of nodal metastasis and distant recurrence; an independent adverse factor in multivariable analyses.
- Recorded as a required element on the RCPath melanoma dataset.
Role in cSCC
- LVI is not a formal criterion in BWH or AJCC 8 cSCC T-staging.
- However, LVI is a required item in the RCPath cSCC dataset and is recognised in NCCN cSCC risk stratification as an adverse feature.
- Practically, LVI in cSCC raises the risk profile and may influence MDT decisions on adjuvant RT, surveillance and lymph-node imaging.
- LVI in head-and-neck cSCC is associated with significantly worse outcomes — discuss at the head-and-neck oncology MDT.
Role in other skin cancers
- Merkel cell carcinoma — LVI strongly associated with nodal metastasis; routine SLNB recommended regardless.
- DFSP, angiosarcoma and other sarcomas — LVI is a major prognostic factor.
- Sebaceous carcinoma, adenoid cystic carcinoma — adverse feature.
References
- Tas F, Erturk K. Lymphovascular invasion as a prognostic factor in cutaneous melanoma — systematic review. Am J Clin Dermatol; 2017.
- Mourouzis C et al. Lymphovascular invasion in cutaneous squamous cell carcinoma — outcomes. Br J Oral Maxillofac Surg; 2011.
- NICE NG14. Melanoma: assessment and management. London: NICE; 2015 (updated 27 July 2022), recommendations 1.4.3-1.4.4.
- Royal College of Pathologists. Dataset for histopathological reporting of primary cutaneous malignant melanoma and regional lymph nodes (G125). London: RCPath; February 2019.
- Royal College of Pathologists. Dataset for histopathological reporting of primary invasive cutaneous squamous cell carcinoma and regional lymph nodes (G124). London: RCPath; February 2019.
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