Case Report: Bone marrow metastasis revealing gastric signet ring cell carcinoma: a case report

<ns3:p> Bone marrow metastasis from gastric adenocarcinoma is uncommon and may present with cytopenias and diffuse skeletal lesions, mimicking primary hematologic disorders. Herein, we report the case of a 53-year-old man of North African descent who presented with a two-month history of epigastric pain, unintentional weight loss, and functional decline. Laboratory testing revealed thrombocytopenia (80 × 10 <ns3:sup>3</ns3:sup> /mm <ns3:sup>3</ns3:sup> ) and markedly elevated alkaline phosphatase (1500 IU/L). Contrast-enhanced computed tomography showed diffuse osteolytic lesions without an evident primary tumor. Bone marrow trephine biopsy demonstrated extensive replacement by a malignant epithelial proliferation. Tumor cells stained positive for cytokeratin, consistent with metastatic carcinoma. Upper gastrointestinal endoscopy identified an ill-defined ulceroinfiltrative lesion along the lesser curvature with friable margins and spontaneous bleeding on minimal touch. Biopsies confirmed poorly differentiated signet ring cell adenocarcinoma. The diagnosis of gastric carcinoma with bone marrow metastasis was then retained. The patient was managed with palliative systemic chemotherapy as well as supportive care and remains alive at 10 months of follow-up. This case highlights that diffuse osteolytic disease with unexplained cytopenias and disproportionate alkaline phosphatase elevation should prompt consideration of occult solid malignancy with marrow involvement. Early bone marrow biopsy with immunohistochemistry can rapidly establish epithelial lineage and should prompt evaluation for an occult gastrointestinal primary malignancy. </ns3:p>