Clinicopathological features of sclerosing angiomatoid nodular transformation of the spleen

Sclerosing Angiomatoid Nodular Transformation of the Laparoscopically Resected Spleen: Case Reports and Review of the Literature

INTRODUCTION

Most splenic tumors are benign; however, it is essential to differentiate them from malignant tumors, such as malignant lymphoma and metastatic tumors. Sclerosing angiomatoid nodular transformation (SANT) is a relatively rare benign tumor that has been reported recently. Splenectomy is performed in most cases of SANT because of the challenges associated with a definitive diagnosis. However, in some cases, SANT can be diagnosed through endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA), and these cases are subsequently followed up. In this report, we present 2 cases of splenic SANT that underwent laparoscopic resection. In Case 1, atypical imaging findings required EUS-FNA for further evaluation. Case 2 exhibited typical imaging findings of SANT, and therefore, EUS-FNA was not performed.

CASE PRESENTATION

Case 1: A 47-year-old female was found to have a 26 mm tumor in the spleen on abdominal ultrasonography during follow-up for gallbladder polyps. Abdominal computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography-CT were performed. EUS-FNA was performed because of the high surgical risk associated with pulmonary hypertension and because hemangioendothelioma, an intermediate malignancy, was suspected. Subsequently, laparoscopic splenectomy was performed, and SANT was diagnosed. Case 2: A 46-year-old female had an incidental detection of a tumor in the spleen on CT. SANT was suspected based on CT and MRI findings. Malignancy could not be completely ruled out owing to the gradual growth of the mass; therefore, the patient was referred to our hospital for surgery. Laparoscopic splenectomy was performed, and SANT was subsequently diagnosed.

CONCLUSION

SANT is a benign tumor that is difficult to diagnose; however, in some cases, it can be diagnosed using EUS-FNA. We report 2 cases of SANT of the spleen that underwent laparoscopic resection. In cases where the diagnosis is confirmed through imaging or histological examination, disease management with follow-up and without surgery is a possible alternative.

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.

Clinicopathological analysis of sclerosing angiomatoid nodular transformation in the spleen

Background

Splenic sclerosing angiomatoid nodular transformation (SANT) is a rare benign nodular lesion in the red medulla of the spleen. In the past, SANT has not been consistently recognized as the name for this condition and was often misdiagnosed for other conditions. In recent years, SANT has been acknowledged by most scholars as multiple reports have been published.

Aim

To assess the clinicopathological features of SANT to identify the histological characteristics of SANT to improve diagnosis and clinical treatment.

Materials and Methods

We assessed 25 cases of SANT diagnosed at Zhongshan Hospital affiliated with Fudan University from September 2014 to October 2021, including 14 men and 11 women, aged 24-62 years old.

Results

Fourteen cases were complicated with benign tumors of the liver, pancreas, kidney, uterus, and prostate. One case was complicated with renal clear cell carcinoma, and one was complicated with hepatocellular carcinoma. The gross neoplasm is multinodular and well defined. Histologically, angiomatoid nodules are composed of fattened, round, or irregular blood vessels, with or without red blood cells in the lumen, with unequal red blood cell extravasation, and fibrocytes around the nodules. The hemangiomatous nodules were positive for CD31 and CD34, while the vascular wall smooth muscle cells and fibrocytes around the nodules were positive for SMA.

Conclusion

The diagnosis of SANT requires a combination of immunohistochemical and histological features, and early splenectomy is crucial for treatment.

Controversies in the Spleen: Histiocytic, Dendritic, and Stromal Cell Lesions

Histiocytic, dendritic, and stromal cell lesions that occur in the spleen are challenging diagnostically, not well studied due to their rarity, and therefore somewhat controversial. New techniques for obtaining tissue samples also create challenges as splenectomy is no longer common and needle biopsy does not afford the same opportunity for examination of tissue. Characteristic primary splenic histiocytic, dendritic, and stromal cell lesions are presented in this paper with new molecular genetic findings in some entities that help differentiate these lesions from those occurring in non-splenic sites, such as soft tissue, and identify possible molecular markers for diagnosis.

Conventional and contrast-enhanced ultrasound of scleroring angiomatoid nodular transformation of the spleen

Sclerosing angiomatoid nodular transformation (SANT) is an uncommon non-tumorous disease of the spleen. The low morbidity and non-specific clinical symptoms of SANT might cause a misdiagnosis. The present study reported a case of a 31-year-old female with a SANT of the spleen. Findings on clinical manifestations and examinations, especially on contrast-enhanced ultrasound (CEUS), were carefully analyzed, and relevant literatures have also been reviewed.