Discovered in approximately 1.3% cases at the time of primary tumor presentation, cutaneous metastases of cancers are extremely rare. The phenomenon generally occurs several years after primary diagnosis or resection of the primary tumor, commonly secondary to malignant melanoma, cancer of the lung, or breast cancer. Cutaneous metastases occur in 4% to 6.5% of metastatic cancer cases, with the abdominal skin as the most common site of manifestation. As there is no standardized treatment so far, the presentation of cutaneous metastases typically indicates poor prognosis and short survival times.
Patterns of Cutaneous Metastases
The patterns of cutaneous metastases vary among men and women. In men, melanoma, lung cancer, and colorectal cancer are the most common sites of cutaneous metastases, while breast cancer, colorectal cancer, and melanoma frequently metastasize to the skin in women. In addition, metastases have also been associated with cancers of gastric, esophageal, prostatic, ovarian, hematologic, laryngeal, palatine-tonsillar, pancreatic, parotid, thyroid, uterine origin, and others. Cutaneous metastases may occur through lymphogenous spread, intravascular dissemination, direct extension of tumors, surgical implantation, and a spread along embryonal remnants.
Manifestation of Cutaneous Metastases in Patients
Cutaneous metastases can present in a variety of clinical manifestations, including rapidly growing painless dermal or subcutaneous nodules with intact overlying epidermis or they can mimic inflammatory dermatosis. Among the most common presentations of cutaneous metastases are ulceration, nodules, bullae, and fibrotic processes.
A new patient case report published in the New England Medical Journal identifies a recent case of cutaneous colorectal cancer metastasis.
Referred to a dermatology clinic with a possible case of shingles, a 59-year-old man with metastatic colon cancer presented with a 10-week history of painless, non-pruritic skin lesions located around a large abdominal scar from a hemicolectomy performed 3 years prior. Both a liver resection and cholecystectomy were performed through the same incision. Under examination, the lesions were firm, pink to violaceous in color, appeared vesicular, and revealed the presence of ascites.
Dermatologists concluded that cutaneous metastases was the most likely cause of these skin changes, confirming the diagnosis of metastatic colon adenocarcinoma with a skin biopsy. As seen in this patient’s case, the most common site of cutaneous metastases in cases of colon adenocarcinoma is the abdominal skin, in or around surgical scars. Unfortunately, the patient received hospice care and died 5 months after cutaneous presentation.
The type of metastasis described in this case occurred through the contact of tumor cells with the outside skin as a result of tumor extraction. This underscores the importance of wound protectors, which are often used during surgery and can help protect the skin from unintended tumor cell implantation, to prevent this type of fatal metastasis.
Cutaneous cancer metastases are usually indicative of widespread disease resulting in survival rates ranging from 1 to 34 months and a mean survival of 4.4 months. Treatment modalities are currently limited and there is a persistent lack of standardized strategy for such cases; management techniques are based on systemic chemotherapy and surgical resection. In metastatic colorectal cancer, surgical resection may offer the possibility of long-term survival, however, outcomes vary.
Although rare in prevalence, the phenomenon remains important and should not be ignored as early diagnoses is critical to effective management of the condition and can help support improved disease prognosis. The latest patient case report underlines the pressing need for the further investigation of more effective therapeutic methods in the coming years.