Primary Gastric Squamous Cell Carcinoma: Challenges in Treatment Strategy

Primary gastric squamous cell carcinoma (GSCC) is an extremely rare malignancy, accounting for approximately 0.04-0.07% of all gastric malignant tumours. The disease carries a poor prognosis, and there is currently no globally standardised treatment protocol.

A 59-year-old female patient with no significant medical history presented with prolonged epigastric pain. Gastroscopy revealed a 5 × 7 cm ulcerated mass along the greater curvature of the gastric body; biopsy confirmed squamous cell carcinoma. Computed tomography (CT) demonstrated tumour invasion through the serosa with perigastric fat infiltration and multiple perigastric lymph nodes >1 cm (the largest node in station 10 measuring 5 cm); tumour marker CA72-4 was elevated at 29.3 U/ml. Comprehensive evaluation revealed no primary lesions at other sites, including esophagogastroduodenoscopy, colonoscopy, chest CT and physical examination. Primary squamous cell carcinoma of the gastric body, cT4N2M0. The patient underwent total gastrectomy, distal pancreatectomy, splenectomy and D2+ lymphadenectomy (including stations 12b, 12p, 13). Histopathological examination confirmed poorly differentiated squamous cell carcinoma with serosal invasion, invasion into the greater omentum, lymphovascular invasion (LVI+) and perineural invasion (PNI+), with 7/25 lymph nodes positive for metastasis. Immunohistochemistry showed diffuse positivity for p63, CK5/6 and CK7; p16 was negative. Post-operative staging: pT4bN3aM0, LVI+, PNI+. The patient received adjuvant chemotherapy with eight cycles of the XELOX regimen.

GSCC is a rare disease entity with a poor prognosis. Radical resection combined with adjuvant chemotherapy represents a reasonable approach for resectable disease. Multicentre studies and clinical trials are needed to establish optimal treatment protocols for this rare malignancy.

Diagnosis requires systematically excluding other primary squamous cell carcinoma sites (oesophagus, lung, head and neck) before confirming primary gastric squamous cell carcinoma (GSCC).Radical resection (R0) combined with aggressive adjuvant chemotherapy is the optimal treatment strategy, offering the best survival chance even in advanced disease (pT4bN3aM0, LVI+/PNI+).Treatment must be individualised due to a lack of standardised protocols: for this extremely rare malignancy, the decision between upfront surgery versus neoadjuvant chemotherapy should be based on tumour resect ability, biological characteristics and multidisciplinary tumour board discussion.