Cutaneous Metastases
Cutaneous metastases occur when cancer cells from a primary malignancy deep in an internal organ or the blood-forming system spread to, invade and grow in the skin and subcutaneous tissue. Their appearance signals that the cancer has reached an advanced stage (stage IV), or that a previously treated malignancy has quietly recurred.
Skin metastases develop in roughly 0.7%–10.4% of all people with cancer. The most common primary sources differ markedly between the sexes:
- Women: Breast cancer is by far the leading source (over 70% of skin metastases in women), followed by melanoma, colorectal, lung and ovarian cancer.
- Men: Lung cancer is the most frequent source (about 25–30%), followed by colorectal cancer, melanoma, renal cell carcinoma (RCC) and head and neck cancers.
At the molecular level, cancer reaches the skin by three main routes: the lymphatics (most common in breast cancer), the bloodstream (typical of lung and kidney cancer and melanoma), or direct seeding along a previous surgical incision or invasive procedure. Tumor cells break away from the primary mass through epithelial–mesenchymal transition (EMT), travel in the circulation and lodge in the skin's dense capillary network through integrin–selectin interactions. They then release vascular endothelial growth factor (VEGF) to build new blood vessels and grow into a metastatic nodule.
At Haute-Derma, we see early recognition of skin metastases as the key to getting the right diagnosis, avoiding misguided cosmetic procedures and returning patients quickly to systemic oncology care.
Clinical Features and Morphologic Types
Skin metastases take many forms and can easily masquerade as benign skin conditions or primary skin tumors:
- Nodular metastases (the most common type):
- Firm, fairly well-defined nodules in the dermis or subcutis that are painless or only slightly tender.
- Color varies: skin-colored, pink, bright red, deep plum, or very dark to black (typical of metastatic melanoma).
- They usually appear singly or in clusters on skin near the primary tumor, for example on the chest wall in breast cancer or the abdominal wall in gastrointestinal cancer.
- Carcinoma erysipeloides: A red, swollen, warm, tender and sharply bordered patch that closely resembles dermatitis or erysipelas. It is most often seen on the chest wall in metastatic breast cancer, where tumor cells block the dermal lymphatics.
- Carcinoma en cuirasse: Skin of the chest or back becomes infiltrated, hardened and thickened like a wooden breastplate, losing its normal elasticity. This is an advanced, fibrosing form of lymphatic spread.
- Alopecia neoplastica: Firm, shiny, scarring patches of hair loss on the scalp that are easily mistaken for benign alopecia areata or fibrosing patterned hair loss.
- Sister Mary Joseph nodule: A hard, rough or ulcerated nodule right at the navel. It is a classic sign of metastasis from pelvic and abdominal cancers, especially gastric, colorectal, ovarian and pancreatic cancer.
Diagnosis and Clinical Management at Haute-Derma
When a patient develops unusual firm lumps under the skin or a rapidly spreading red, hardened patch, Haute-Derma follows a structured diagnostic pathway:
Dermoscopy and Oncologic History
- Digital dermoscopy: We look for abnormal vessels (serpentine or comma-shaped, irregularly branching), structureless pigment-free areas, or the characteristic deep plum color.
- Detailed medical history: We record every previous cancer diagnosis, tumor surgery, course of chemotherapy or radiotherapy, and any earlier recurrences.
Cosmetic Procedures on the Lesion Are Strictly Contraindicated
- No mesotherapy, laser, squeezing, incision or liposuction: Cosmetic procedures (fat-dissolving injections, mesotherapy, thermal laser, microneedling) and trial squeezing or lancing must never be performed on these lesions. Inappropriate manipulation can rupture the tumor, seed cancer cells across the skin surface and destroy the margins needed for biopsy.
Skin Biopsy and Immunohistochemistry (IHC)
To pin down the origin of the primary tumor, the doctor takes a skin biopsy:
- Biopsy technique: A punch or excisional biopsy that includes the full thickness of the dermis and subcutis.
- Immunohistochemistry (IHC) panel:
- CK7 / CK20: CK7+/CK20− points toward breast, lung or ovarian cancer; CK7−/CK20+ points toward colorectal cancer.
- TTF-1: Strongly positive in lung and thyroid cancer.
- GATA3 / mammaglobin: Specific markers of breast cancer.
- CDX2: Specific for gastrointestinal cancers (stomach, colon).
- PAX8: Positive in ovarian cancer and renal cell carcinoma (RCC).
- Melan-A / SOX10 / S100: Positive in metastatic melanoma.
Referral to Oncology
We prepare a specialist case file and refer the patient straight to an oncology center for:
- Whole-body PET/CT or multislice CT to stage the spread of disease and locate the primary tumor if it is not yet known.
- A multidisciplinary team (MDT) review to restart or change chemotherapy, targeted therapy or immunotherapy.
