Unusual locations of involvement by malignancies: Case 3. Gastric signet ring carcinoma presenting as a diffuse thigh mass

Isolated brachioradialis metastasis of gastric adenocarcinoma after R0 resection

BACKGROUND

Gastric cancer is the fifth most common cancer worldwide, with an incidence of 6.72 per 100,000 people. Thirty-two percent of gastric cancer patients will live 5 years after diagnosis. Single-site metastasis is noted in 26% of patients with gastric cancer, most commonly in the liver (48%), peritoneum (32%), lung (15%), and bone (12%). Here, a case is presented in which a single skeletal muscle metastasis appeared after appropriate resection and treatment.

CASE PRESENTATION

A 63-year-old man underwent neoadjuvant chemotherapy and a multivisceral en bloc R0 resection. Final pathology showed no evidence of lymph node metastasis with 31 negative lymph nodes. Four months postoperatively, the patient was found to have a rapidly growing biopsy-proven extremity soft tissue gastric metastasis within the brachioradialis muscle. He subsequently underwent metastasectomy and immunotherapy.

CONCLUSION

This case is a rare example of an isolated extremity metastasis of gastric adenocarcinoma in the setting of an R0 resection of the primary tumor and negative nodal disease on final pathology, suggestive of hematogenous spread. We review the biology, workup, and management of gastric cancer and highlight new advancements in the treatment of this aggressive cancer.

Metastatic involvement of skeletal muscle from gastric adenocarcinoma

Gastric cancer represents the fifth most common cancer diagnosis worldwide and the third leading cause of cancer-related mortality. In the USA, the overall 5-year survival rate is 31%, with distant disease nearing 5%. The most common sites of metastasis are the liver and peritoneum. Skeletal muscle involvement has been rarely reported. Since clinical and imaging findings overlap with primary sarcomas, a confirmatory biopsy is required for diagnosis. Prognosis remains poor with treatment options including palliative chemotherapy, radiotherapy and surgical resection. We report the case of a 57-year-old female presenting with extensive involvement of skeletal muscle 10 years after achieving remission. In addition to illustrating the refractoriness and poor outcomes associated with muscle involvement, this case and comprehensive review of the literature highlights important characteristics of disease biology and tumor genomics that warrant detailed discussion and exposition to a wider audience.

[Metastasis in the palatine tonsil as the first sign of a gastric adenocarcinoma]

Gastric adenocarcinomas rarely give rise to metastases in the palatine tonsils; twelve such cases have been published. In two of them the tonsillar tumour was the first sign of the disease. We present a patient with a tumour of the palatine tonsil and cervical lymph node involvement who was diagnosed as having an adenocarcinoma of "signet ring" cells in the histopathology and cytology studies. Finding such cells directed us to the stomach in our search for the primary.