Cutaneous Metastasis of Gastric Adenocarcinoma at the Site of a Traumatic Ecchymosis

To the Editor:

In a recent Cutis^® article, Cesaretti et al¹ reported a case of cutaneous metastasis from primary gastric cancer that appeared on a resection scar 6 years after remission and without any relapse of the primary tumor. We report a case of a 68-year-old man who was referred to the dermatology clinic with a 15×20-cm nonpruritic, nonscaly, bruiselike lesion on the right forearm of 1 month’s duration. Approximately 1.5 years prior to presentation, the patient was diagnosed with gastric adenocarcinoma (stage IV: T4N3M1) with hepatic and lung metastasis. Following 6 months of chemotherapy with cisplatin and 5-fluorouracil, a positron emission tomography–computed tomography scan was performed and showed a reduction in metastasis but growth of the primitive tumor. After 1 year of chemotherapy, the new positron emission tomography–computed tomography scan showed no metastases. However, the primitive tumor had increased in size.

One month prior to presentation to the dermatology department, a traumatic blood sample on the right forearm left the patient with a persistent ecchymosis. The lesion was thought to be a healing ecchymosis and no biopsy was performed. One month later, the skin lesion had become much thicker and more erythematous (Figure) but not larger. A skin biopsy of this well-defined plaque was performed. Histologic examination showed neovascularization, proliferative epithelial cells, and cytokeratin markers AE1/AE3 and CK20, leading to the diagnosis of skin metastasis of the gastric adenocarcinoma. Chemotherapy was discontinued because of the patient’s altered general status and palliative care was given until he died the following month (2 months after presentation).

Skin metastasis on the right forearm (anterior view).

Iatrogenic dissemination of cancer cells has been described often on scars of tumor surgery,² and in malignant melanoma, bruises and hematoma revealing preexisting metastases have been reported.^3,4 Our report of secondary metastasis on an ecchymosis suggests that the traumatic blood sample performed before the development of the metastasis caused circulating tumor cells in the skin, which led to their local proliferation. The skin metastasis was the first sign of relapse and was followed by alteration of the general status and death.

Our patient is an example of the “soil and seed”⁵ hypothesis. Our case illustrates the abilities of tumor cells to colonize the skin under favorable conditions and emphasizes the importance of minimizing bleeding events and iatrogenic seeding of internal neoplasms in daily practice.