Context: Splenic metastases from solid tumors, defined as parenchymal lesion, are considered exceptional. Nevertheless, the number of case reports has been increasing due to the improvement of imaging techniques and the long-term follow-up of patients with cancer. Splenic metastases occur in a context of multivisceral disseminated cancer or as a solitary lesion.
Objective: To provide a general overview of the clinicopathologic features, differential diagnosis, and pathogenesis of splenic metastases.
Data sources: Relevant articles indexed in PubMed (National Library of Medicine) database. The search was based on the following terms: (metastasis or metastases) and spleen.
Conclusions: The most common primary sources of splenic metastasis are breast, lung, colorectal, and ovarian carcinomas and melanoma in cases of multivisceral cancer and colorectal and ovarian carcinomas in cases of solitary splenic lesion. Splenectomy can be replaced by less aggressive methods such as fine-needle aspiration or percutaneous biopsy for establishing the diagnosis of solitary splenic metastasis. The main differential diagnoses are primary lymphoma, vascular tumors, and infectious lesions of the spleen. The relative rarity of splenic metastases could be explained by anatomic factors and the inhibitory effect of the splenic microenvironment on the growth of metastatic cells. The analysis of clinical case reports suggests that solitary splenic metastases may result from the growth of an early blood-borne micrometastasis following a period of clinical latency, often several years after the diagnosis of the primary tumor.