Gastric Adenocarcinoma with Bone Marrow Metastasis

Introduction

Gastric cancer, as a common gastrointestinal malignancy, demonstrates a low clinical detection rate of bone marrow metastasis. Nevertheless, it ranks first among primary carcinomas causing metastatic bone marrow involvement.[1] Despite recent advances in precision oncology that have improved the overall prognosis of malignancies, patients with gastric cancer bone marrow metastasis still face dismal survival outcomes. This article describes a rare case of bone marrow metastasis in a female patient with gastric adenocarcinoma, detected by ¹⁸F fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F FDG PET/CT) without evident bone destruction on conventional CT imaging.

Case Report

A 64-year-old female was admitted to the hospital with generalized pain and fatigue for 5 days. Laboratory results showed hemoglobin of 36 g/L and platelet count of 42.00 (×10⁹/L) with preserved leukocyte count. Diagnostic workup included ¹⁸F FDG PET/CT demonstrating: Axial fused [Figure 1] images indicated thickening of the gastric wall in the antrum and increased FDG uptake. In addition, multiple lymph node lesions were identified around the stomach, exhibiting increased FDG uptake [Figure 2]. The coronal fused image [Figure 3] showed increased FDG uptake in the axial and appendicular skeleton. Coronal CT images [Figure 4] showed no signs of bone destruction in the corresponding parts. The sagittal maximum intensity projection image [Figure 5] and axial image [Figure 6] simultaneously demonstrate increased FDG uptake in the gastric antrum wall and multiple skeletal sites throughout the body. Subsequently, the patient underwent gastroscopy and right anterior superior iliac spine puncture bone marrow biopsy. Histological view of the biopsy tissue [Figures 7 and 8, Hematoxylin and Eosin, ×20] obtained at endoscopy, showing multiple poorly differentiated adenocarcinoma cells. Bone marrow biopsy [Figure 6, Wright-Giemsa, original magnification ×1000] revealed multiple adenocarcinoma cells. Immunohistochemical studies showed that CK (pan)⁺, CK7⁺, CK19⁺, CK20⁻, Mucin-5AC⁺, CD56⁺, CDX2⁻, TTF-1⁻, Mucin-2⁻, CD45⁻, CD3⁻, Pax-5⁻, CD10⁻, CD68⁻, CD42b⁻. As such, the diagnosis of gastric adenocarcinoma with widespread bone marrow metastases was finally made. In our case, the patient passed away after 28 days after diagnosis.

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Figure 1 Axial fused images indicated thickening of the gastric wall in the antrum and increased fluorodeoxyglucose uptake

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Figure 2 Multiple lymph node lesions were identified around the stomach with increased fluorodeoxyglucose uptake

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Figure 3 The fused image showed increased fluorodeoxyglucose uptake in the axial and appendicular skeleton

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Figure 4 No signs of bone destruction in the corresponding parts

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Figure 5 The sagittal maximum intensity projection image simultaneously demonstrates increased fluorodeoxyglucose uptake in the gastric antrum wall (marked by the arrow) and multiple skeletal sites throughout the body

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Figure 6 The sagittal axial image simultaneously demonstrates increased fluorodeoxyglucose uptake in the gastric antrum wall (marked by the arrow) and multiple skeletal sites throughout the body

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Figure 7 Gastric adenocarcinoma

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Figure 8 Bone marrow pathological biopsy revealed heteroepithelial cells’ infiltration

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Discussions

Gastric cancer is a common neoplasm and is the third most widespread cause of cancer-related deaths worldwide, which is a cancer type usually diagnosed at an advanced stage.[2] While hepatic, peritoneal, and pulmonary metastases predominate, bone marrow metastasis in gastric cancer is rare, and only a few cases have been reported.[3] The prognosis of patients with gastric cancer complicated with bone marrow metastasis is poor.[4] The patient expired 28 days after definitive diagnosis.

The pathogenesis of bone marrow metastasis in gastric cancer remains poorly understood. Clinical manifestations are heterogeneous, with anemia and thrombocytopenia constituting the predominant clinical features resulting from neoplastic infiltration of the medullary cavity.[5] In this case, the patient presented with generalized bone pain and fatigue, accompanied by laboratory findings of markedly reduced hemoglobin and platelet levels. The clinical detection rate of gastric cancer-associated bone marrow metastasis is remarkably low (0.7%), whereas autopsy studies reveal a significantly higher incidence (17.6%), suggesting substantial underdiagnosis in clinical practice.[6] ¹⁸F FDG PET/CT serves as a highly sensitive modality for detecting bone marrow metastases.[7] In our case, ¹⁸F FDG PET/CT demonstrated increased metabolic activity in the gastric antrum, axial skeleton, and appendicular bones, while corresponding CT images showed no evidence of bone destruction.

In addition, this case demonstrates the advantage of PET/CT in detecting hidden primary lesions and distant metastases, particularly its critical role in detecting extensive bone marrow involvement without concomitant structural bone abnormalities.