American Urological Association - Squamous Cell Carcinoma
Squamous Cell Carcinoma
- Most common malignant tumor of the penis.
- Incidence: South America, Africa and Asia > North America.
- Predisposing factors: lack of circumcision, poor hygiene, phimosis, smoking and HPV infection.
- More frequent in men >50 years old.
- 30-40% of all SCC are HPV-related (High-risk genotypes are 16 and 18).
- Basaloid and condylomatous (warty) SCC are HPV related (with p16 overexpression).
- Verrucous, psedohyperplastic and cuniculatum SCCs are HPV-unrelated.
- Patterns of growth: superficial spreading (broad horizontal superficial extension), vertical (deeply infiltrative), verruciform (superficial cauliflower growth), multicentric (>2 sites).
- Vertical growth has higher rate of nodal involvement and poorer outcome.
- Typical location is glans penis, coronal sulcus or prepuce (distal penis) (image A).
- For usual type, keratinization related to differentiation (mostly have obvious keratin – well to moderately differentatied) (image B).
- Other types include pseudohyperplastic (associated with lichen sclerosus, low grade in elderly), warty (condylomatous, with koilocytes) (image C), verrucous (see later), papillary, basaloid (non-keratinizing small to intermediate cells), sarcomatoid (spindle cell), cuniculatum (verrucous with deep burrowing and cobblestoning) and mixed.
- p16 immunostain is a marker for high risk HPV and SCC with basaloid features and high grade nonbasaloid are likely to be more positive than low grade keratinizing SCC (image D).
- Metastases: SCCa of the penis tends to be locally invasive but may metastasize to inguinal lymph nodes; hematogenous spread is relatively uncommon, despite the rich vascularity of the corpora cavernosa.
- Verrucous and psedohyperplastic SCCs have low risk for nodal metastasis.
- Basaloid, sarcomatoid, adenosquamous, and poorly differentiated usual SCCs have higher risk for nodal involvement.