Clinicopathological analysis of sclerosing haemangiomatoid nodular transformation of the spleen: analysis of three cases and a literature review.

Objective: To examine the clinicopathological features, immunohistochemical profiles, and differential diagnosis of sclerosing angiomatiod nodular transformation (SANT).

Methods: Three cases of SANT of the spleen, diagnosed between 2014 and 2023 at the Affiliated Hospital of Zunyi Medical University, were analysed. Pathological features were assessed using haematoxylin and eosin staining, followed by immunohistochemistry with the EnVision system. Additionally, a review of relevant literature was conducted.

Results: The study included one male and two female patients aged 40-55 years, with a median age of 47.5 years. All lesions were solitary, with tumour diameters ranging from 4 to 7.4 cm (mean 5.7 cm). Gross examination demonstrated that the masses were well-demarcated from the surrounding splenic tissue, with no evident capsule. The cut surfaces of the masses exhibited irregular, porcelain-white nodules that were tough in consistency, with some areas intermingling with splenic tissue. Microscopic examination revealed round or circular nodules comprising multiple slit-like or sinusoidal capillaries, separated by concentric collagen fibres. The nodules exhibited chronic inflammatory cell infiltration, calcification, haemosiderin deposition, and fibrous connective tissue with hyaline or mucoid changes. Immunohistochemical analysis demonstrated differential expression of markers, including cluster of differentiation (CD) 34, CD31, and CD8, within the sinusoidal nodule areas. Periodic acid-Schiff staining was positive for perinodular collagen deposits, while reticulin staining highlighted nodule profiles and intranodular vessels. None of the patients experienced postoperative recurrence or metastasis, and one patient was on aspirin for thrombocytosis.

Conclusion: SANT of the spleen is generally considered a rare, benign lesion with angioma-like characteristics. It exhibits exhibiting distinctive histomorphological features within the red pulp. Understanding the differential diagnosis is crucial to prevent missed or incorrect diagnoses.