Granular cell tumor, histopathology, S-100

Diagnosis: Granular cell tumor, histopathology, S-100

S100 immunostain

Clinical Presentation

S100 immunostain

Clinical History

Submitted by dermRounds Dermatology Network. Originally posted June 27, 2008.

Treatment

See case discussion.

Differential Diagnosis

• Keratoacanthoma • Basal cell carcinoma • Actinic keratosis (hypertrophic) • Verruca vulgaris • Bowen disease • Amelanotic melanoma • Prurigo nodularis

Key Learnings

• Second most common skin cancer — arises from keratinocytes • UV radiation is the primary cause; UVB induces p53 mutations • Risk hierarchy: immunosuppression (organ transplant recipients 65-250× risk), chronic wounds/scars (Marjolin ulcer), radiation, arsenic • High-risk features: >2cm, poor differentiation, perineural invasion, location (ear, lip), immunosuppression, depth >6mm • SCC of the lip and ear has higher metastatic potential (~5-10%) vs. sun-exposed skin (~2-5%) • Organ transplant recipients: SCC:BCC ratio reverses (SCC becomes more common) • Cemiplimab (anti-PD-1) approved for advanced/unresectable cutaneous SCC

Tags: granular, cell, tumor, histopathology, 100, dermrounds dermatology network