Diffuse Bone Metastases as the Initial Presentation of Gastric Adenocarcinoma: A Rare and Atypical Case Report

Background: The occurrence of skeletal metastases is generally indicative of an adverse prognosis. Despite the immediate negative impact of bone involvement on cancer outcomes, accurate identification of the primary tumour is critical. Aim: We report the unusual case of a 58-year-old man who initially presented with persistent right shoulder pain that rapidly became generalized and refractory to standard analgesics, in a context of profound functional decline and significant weight loss. Diagnostic evaluation revealed a poorly differentiated gastric adenocarcinoma with upfront bone metastases. Discussion: Bone dissemination occurs in approximately 10% of gastric cancers and is therefore relatively rare. The originality of this case lies in its inaugural presentation as isolated bone pain in the absence of typical gastrointestinal symptoms, associated with bicytopenia and markedly elevated serum tumor markers. Conclusion: This case underscores the importance of considering an underlying digestive malignancy in patients presenting with unexplained bone disease, particularly when biological abnormalities are suggestive.