Scalp and Neck Metastasis From HER2-Positive Gastric Cancer: A Case Report and Literature Review

Cutaneous metastasis of gastric cancer is a rare manifestation (2.6%) of advanced gastrointestinal cancers and occurs in less than 1% of upper GI tract malignancies. The nodular type is the most common type. Tissue diagnosis and anatomic localization of the primary tumor are best obtained by upper gastrointestinal endoscopy. However, when the patient presents with dermatological and scalp lesions, the procedure is to take a targeted biopsy of said lesions.

A 60-year-old female with advanced disease (Stage IV HER2-positive gastric cancer) was diagnosed due to skin metastases: erythematous alopecic skin lesions on the central scalp, as well as a raised, erythematous, indurated, nontender, irregular 6 × 8 cm lesion on the cervicodorsal region. Treatment with capecitabine + oxaliplatin + trastuzumab every 3 weeks was initiated. By the sixth cycle, the scalp lesion had resolved completely, and the cervical lesion had reduced to 3 × 4 cm. After 1 year of treatment, the lesions continued to show a favorable response.

To the best of our knowledge, this is the second reported case of cutaneous metastases from HER2-positive gastric cancer. Fewer than 20 cases involving metastases to the scalp and neck region have been reported in the English-language literature.