Littoral cell angioma of the spleen: A study of 10 cases case series and literature review.

Background: Current study aimed to investigate the clinical characterization, differential diagnosis, and treatment of splenic littoral cell angioma (LCA).

Methods: A retrospective analysis was performed for 10 LCA cases admitted to Huzhou Central Hospital from 2007 to 2023, for clinical manifestations, hematological tests, imaging features, pathological features, treatment methods, and prognosis along with the relevant literature was also reviewed.

Results: During examinations, no specific clinical manifestations and hematological abnormalities were seen in all 10 cases of LCA. Imaging observations depicted single or even multiple spherical lesions in the spleen. Plains shown by computed tomography (CT) were found somewhat equal or slightly lower in density. On the other hand, magnetic resonance imaging (MRI) plain scans viz. T1 weighted image showed equal low and mixed signals while T2-weighted showed high and low mixed signals. Moreover, punctate low signals could be seen in high signals named "freckle sign" in MRI scans. On contrast-enhanced CT scans, the enhancement of the lesions was not obvious in the arterial phase, and some of the lesions showed edged ring-like enhancements and "filling lake" progressive enhancement during the venous phase and delayed phase. In multiple lesions, the number of enhanced scan lesions showed a variable changing pattern "less-more-less." MRI-enhanced scan showed the characteristics of "fast in and slow out." Microscopic examinations identified tumor tissue actually composed of sinus-like lacunae that anastomosed with each other in the form of a network. Furthermore, cystic expansion and pseudopapillary protrusions were also seen in the dilated sinus cavity which was lined with single-layer endothelial cells having conspicuous cytoplasmic hemosiderin. High immunophenotypic expressions of vascular endothelial cell phenotype (CD31, CD34, FVIII) and tissue cell phenotype (CD68) were also seen. Total and partial splenectomy were performed in 8 and 2 patients, respectively, and follow-up examinations showed survival in all patients with no recurrence.

Conclusion: LCA is a rare splenic benign lesion with atypical clinical manifestations. CT and MRI imaging are important tools in preoperative diagnosis based on pathomorphological and immunohistochemical examinations. Splenectomy is a superior therapeutic choice with significant impacts and prognosis.