Summary of Nonmelanocytic Skin and Soft Tissue Tumors
Nonmelanocytic Skin and Soft Tissue Tumors: Guide for Students
Introduction
Cutaneous malignant tumors are cancers that arise from the skin’s epithelial or adnexal structures. They vary widely in behavior from locally destructive lesions to aggressive cancers with significant metastatic potential. This guide focuses on the clinical features, typical presentations, and practical management principles of the principal cutaneous malignant tumors described in the source text.
Definition: Cutaneous malignant tumors are neoplasms originating from epidermal, appendageal, or mesenchymal components of the skin that demonstrate invasive growth and potential for local destruction or distant spread.
Major groups covered
- Epithelial-origin tumors: Squamous cell carcinoma (SCC), Basal cell carcinoma (BCC)
- Appendage-origin tumors: Sebaceous carcinoma, Trichilemmal carcinoma, Sweat gland carcinomas
- Neuroendocrine tumor: Merkel cell carcinoma
- Dermal mesenchymal tumors: Dermatofibrosarcoma protuberans (DFSP), Malignant fibrous histiocytoma (MFH)
- Intraepidermal adenocarcinoma: Extramammary Paget’s disease (EMPD)
Squamous Cell Carcinoma (SCC)
Clinical features
- Often an elevated, indurated lesion with ulceration and crusting.
- Common on chronically damaged or scarred skin: actinic damage, postburn scars (Marjolin’s ulcer), traumatic scars, chronic ulcers, chronic radiation dermatitis.
- May have secondary infection and a foul odor from macerated keratin and necrotic tissue.
Definition: Squamous cell carcinoma is a malignant tumor of keratinocytes that frequently arises in sun-damaged or chronically inflamed skin and may ulcerate and invade locally.
Practical points
- Always perform a differential diagnosis vs BCC and infected/ulcerated benign lesions.
- Preferred treatment: surgical excision; Mohs micrographic surgery often used to spare tissue and ensure margins.
- Radiotherapy (external-beam or brachytherapy) is an option for selected patients.
Basal Cell Carcinoma (BCC)
Clinical features
- Most common skin cancer; locally invasive but rarely metastasizes.
- Common on the head and neck; causes cosmetic morbidity due to local destruction.
- Multiple histologic subtypes with differing behavior (see comparison table).
Definition: Basal cell carcinoma is a locally invasive malignant tumor originating from basal keratinocytes, characterized by slow growth and rare metastasis but potential for significant local tissue destruction.
Management
- Standard: surgical excision; Mohs micrographic surgery is frequently used for cosmetically or functionally important sites.
- For superficial BCC in selected cases: CO2 laser or cryosurgery may be appropriate alternatives.
Table: Histologic subtypes of BCC and key features
| Subtype | Typical behavior / notes |
|---|---|
| Multifocal superficial BCC | Multiple superficial patches, may be amenable to topical therapy or superficial ablation |
| Nodular BCC | Classic pearly nodule, common on face |
| Infiltrating / sclerosing BCC | More aggressive, ill-defined margins |
| Fibroepithelial BCC | Often on trunk, pedunculated |
| Basosquamous carcinoma | Shows squamous differentiation; may behave more aggressively |
| Keratotic / Pigmented / Micronodular | Variants with clinical differences; pigment or keratinization may be present |
Appendageal and Adnexal Malignancies
These arise from hair follicles, sebaceous glands, sweat glands, or related adnexal structures.
Sebaceous carcinoma
- Examples: Meibomian gland carcinoma (eyelid), Zeis gland carcinoma.
- Typical features: erosion, ulceration; eyelid lesions can be mistaken for benign blepharitis or chala
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Cutaneous Malignant Tumors
Klíčové pojmy: Biopsy any nonhealing, indurated, or ulcerated skin lesion promptly, SCC often arises in chronically damaged or scarred skin and may produce a foul odor, BCC is the most common skin cancer and is locally destructive but rarely metastasizes, Mohs micrographic surgery is preferred for margin control in cosmetically/ functionally important sites and for DFSP, EMPD mimics eczema; mapping biopsy helps define surgical margins, Merkel cell carcinoma is aggressive, often linked to polyomavirus, and requires wide excision plus nodal evaluation, DFSP frequently harbors COL1A1–PDGFB fusion and needs wide excision to prevent recurrence, Sebaceous and sweat gland carcinomas require wide excision; consider lymph node dissection for advanced disease, Trichilemmal carcinomas arise from outer root sheath and need wide excision, Differentiate SCC from BCC because SCC has higher metastatic risk, Use adjuvant radiotherapy or chemotherapy for nodal or distant metastases when indicated, Atypical fibroxanthoma is a superficial variant of MFH with generally less aggressive behavior