Sclerosing Angiomatoid Nodular Transformation of the Spleen: Multimodality Imaging Findings and Pathologic Correlate

Sclerosing angiomatoid nodular transformation of the spleen: multimodality imaging features and literature review

OBJECTIVE

The purpose of this study was to evaluate the CT and MRI findings, clinicopathologic features, and differential diagnosis of Sclerosing angiomatoid nodular transformation (SANT).

METHODS AND MATERIALS

Seven men and seven women with pathological diagnoses of SANT were included in this retrospect study. Patients underwent at least one radiological examination before surgery. The number, shape, margin, size, attenuation, signal intensity, homogeneity, and enhancing pattern of the lesion were evaluated by two abdominal radiologists independently. Immunohistochemistry reports were available for 11 patients. The immunoreactivity to the vascular markers CD8, CD31, and CD34 was assessed.

RESULTS

The 14 SANT patients (7 men, 7 women; mean age, 43.5 years; age range, 24-56 years) presented with a single lesion and showed no specific clinical symptoms. Among 14 patients, 12 patients underwent MR scan, 5 patients underwent CT scan and 3 patients underwent PET-CT. On CT, all 5 lesions showed hypodensity on non-contrast images and spoke-wheel enhancing pattern after contrast administration, and calcification was observed. On T2WI, 10 cases(83.3%)showed hypointensity and 2 cases (16.7%) showed hyperintensity with central hypointensity. On T1WI, 10 cases (83.3%) were isointense and 2 cases (16.7%) were slightly hypointense. 10 cases (83.3%) showed hypointensity on DWI and 2 cases (16.7%) showed slightly hyperintensity on DWI. After contrast administration, all 12 lesions showed progressive enhancement. 18 F-fluorodeoxyglucose (FDG) uptake in the tumor was seen in all three cases that underwent PET-CT. The maximum standardized uptake value (SUVmax) was 4.5, 5.1, and 3.8 respectively.

RESULTS

Apart from the progressive spoke-wheel enhancing pattern, DWI and ADC findings will add value to the diagnosis of SANT.

Sclerosing Angiomatoid Nodular Transformation of the Spleen: A Diagnostic Conundrum

A splenic lesion often represents a diagnostic challenge due to relative scarcity and the broad differential diagnosis. Sclerosing Angiomatoid Nodular Transformation (SANT) of the spleen is usually encountered only incidentally. Although benign, patients with SANT often receive splenectomy, due to its rarity, diagnostic uncertainty and sometimes intimidating imaging morphology and size. Imaging features on computed tomography, magnetic resonance and positron emission tomography have a high diagnostic value for SANT and help differentiate this entity from other splenic lesions. When the imaging parameters are matched with core needle biopsy tissue analysis, further watchful waiting can be recommended in order to avoid splenectomy.

Sclerosing angiomatoid nodular transformation presenting with thrombocytopenia after laparoscopic splenectomy - Case report and systematic review of 230 patients

Background

Sclerosing angiomatoid vascular transformation (SANT) is a rare vascular disease of the spleen, which is difficult to diagnose due to its pre-intervention appearance of malignancy. Case Report: An 85-year-old male was transferred to our clinic for thrombocytopenia and splenic mass. A contrast enhanced abdominal CT and MRI showed nodular lesions, the largest 50mm in diameter, and several areas of heterogeneous contrast field involvement in the spleen parenchyma. Laparoscopic splenectomy was performed with normal range of platelet level. The patient's postoperative course was uneventful and he was discharged on the 6th postoperative day. Histopathology revealed SANT. The patient is now in the 18 th month of remission with platelet levels within normal range and with no recurrence.

Results

Between 2004 and April 2020, a total of 230 SANT patients who underwent laparoscopic or open splenectomy or biopsy were reported in the literature. Most patients were female (52.1%), and the median age was 46 years (9 weeks-85 years). Most patients were asymptomatic (56%). Open splenectomy was performed on 166 patients (72.1%),laparoscopic splenectomy on 35 patients (15.2%) and laparoscopic partial splenectomy on 15 patients (6.5%). The median operation time and spleen weight were 143 minutes (88-213) and 260gr (68-2,720), respectively. Median follow-up time was 12 months (0-166). No recurrence was seen in patients undergoing total splenectomy.

Conclusion

SANT is an unusual disease of the spleen. In the light of this systematic review, a minimally invasive method for total or partial splenectomy,specifically laparoscopy, can be preferred as the treatment of choice.

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SANT is a rare, benign vascular disease of the spleen.

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The correct diagnosis of SANT pre-intervention or preoperatively is a significant for treatment.

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Laparoscopic splenectomy is curative treatment for SANT.

Laparoscopic Splenectomy in a Patient with Sclerosing Angiomatoid Nodular Transformation

Sclerosing angiomatoid nodular transformation (SANT) of the spleen is a specific, tumor-forming, non-neoplastic, vascular lesion with few reported cases worldwide. Herein, we describe the case of a patient who underwent laparoscopic splenectomy for SANT. A 47-year-old woman underwent upper gastrointestinal endoscopy for suspected gastric submucosal tumor. Contrast-enhanced abdominal computed tomography revealed the presence of a gradually enhancing lesion in the splenic hilum. Although we suspected splenic fibrotic hamartoma, malignancy could not be ruled out. Therefore, the patient underwent laparoscopic splenectomy, resulting in the histopathological diagnosis of SANT. Although SANT is a benign tumor, it may be difficult to obtain definitive diagnosis using preoperative imaging alone. Because the long-term natural history of SANT is unknown, we believe that splenectomy could be an appropriate technique for the diagnosis and treatment of SANT.

Sclerosing angiomatoid nodular transformation (SANT) of the spleen: a case report with FDG-PET findings and literature review

We report the 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) findings of sclerosing angiomatoid nodular transformation (SANT) of the spleen. The patient was a 37-year-old woman with a splenic mass incidentally found on abdominal ultrasound. FDG-PET/CT showed weak FDG accumulation (maximum standardized uptake value = 3.65). An unenhanced CT scan showed a low density and well-circumscribed splenic tumor that demonstrated weak enhancement from the arterial to delayed phase. Although hemangioma or hamartoma of the spleen was preoperatively diagnosed, histopathological examination revealed SANT. Therefore, when a splenic tumor with weak contrast medium enhancement and low FDG accumulation is observed, SANT should be considered as a differential diagnosis. Although CT and magnetic resonance imaging features of SANT have been reported, there are few reports on FDG-PET/CT findings. We report the radiological features of SANT, including FDG-PET/CT, and review the literature on SANT.

Differentiation of an unclear splenic lesion in a patient with cholangiocarcinoma

Here we report on a 51-year-old man with the primary diagnosis of cholangiocarcinoma. Workup with CT and contrast-enhanced ultrasound revealed an additional lesion in the spleen, raising the concern for metastasis. Combined FDG PET/CT revealed a different metabolic pattern, making a metastasis unlikely. Histopathology of the splenic lesion confirmed sclerosing angiomatoid nodular transformation, a rare benign lesion of the spleen.

Two cases of sclerosing angiomatoid nodular transformation of the spleen with gradual growth: usefulness of diffusion-weighted imaging

Sclerosing angiomatoid nodular transformation (SANT) is a recently recognized and rare, nonneoplastic lesion of the spleen. Some papers have reported an increased SANT diameter during the follow-up period. We present two cases of SANT whose size increased during the follow-up period. Diffusion-weighted magnetic resonance imaging (DWI) findings correlated well with the pathological findings of SANT, the multinodular high-intensity area as the angiomatoid nodules and the peripheral low-intensity area as fibrous tissues. Therefore, DWI may be a useful imaging tool.

A case of sclerosing angiomatoid nodular transformation of the spleen: correlations between contrast-enhanced ultrasonography and histopathologic findings

Sclerosing angiomatoid nodular transformation (SANT) is a recently recognized benign vascular lesion of the spleen. Detection of SANT as an incidentaloma has increased due to improvements in imaging techniques. However, a definitive diagnosis of SANT on CT or MRI remains difficult. We report the use of contrast-enhanced ultrasonography with Sonazoid in a case of SANT in a 50-year-old woman, with gross and microscopic pathologic correlations.

Sclerosing angiomatoid nodular transformation of the spleen (SANT): multimodality imaging appearance of five cases with radiology-pathology correlation

OBJECTIVE

Sclerosing angiomatoid nodular transformation (SANT) is an extremely rare splenic lesion first reported in 2004, representing an unusual reaction of splenic red pulp to stromal inflammation or vascular injury. There are very few descriptions of the imaging appearance of SANT in the literature. We present five pathologically proven cases of SANT, with a description of the imaging appearance using multiple different modalities, as well as correlation with the histopathologic features of the lesion.

CONCLUSION

While there are several imaging features of SANT which have been described in the literature, it is not routinely possible to make a prospective diagnosis based on the imaging features alone. Moreover, it may not be possible to exclude malignancy based on the imaging features, and splenectomy may be required in certain cases.

Sclerosing angiomatoid nodular transformation of the spleen

Sclerosing Angiomatoid Nodular Transformation (SANT) of the spleen is a rare benign lesion of the spleen with unknown etiology. SANT is classically considered to be a female-predominant disease, with most of the patients in the 30- to 60-year age group. Most lesions are found incidentally on imaging. Although SANT has specific imaging findings, the differential diagnosis from other splenic tumors or malignant lesions is very difficult. Histopathologically, these tumors reveal multiple confluent angiomatoid nodules; these nodules are surrounded by concentric collagen fibers exhibiting an inflammatory and myofibroblastic response and are accompanied by numerous erythrocytes and siderophages. The nodules are populated by endothelial cells, phenotypically recapitulating normal splenic vasculature, such as sinusoids, capillaries, and small veins. Nuclear atypia is minimal, mitotic figures are extremely rare, and necrosis is consistently absent. This lesion has a unique immunohistochemical profile characterized by CD34(-)CD31(+)CD8(+) sinusoids, CD34(+)CD31(+)CD8(-) capillaries, and CD34(-)CD31(+)CD8(-) small veins. CD68 is positive in macrophages. Splenectomy is a useful and effective technique for the management of SANT. SANT patients have a good prognosis, with no recurrence after splenectomy. In this review, we discuss the current knowledge of SANT of the spleen and its clinical relevance.

Sclerosing angiomatoid nodular transformation of the spleen: CT and MRI features with pathologic correlation

OBJECTIVE

The objective of this study was to describe the CT and MRI features of sclerosing angiomatoid nodular transformation of the spleen with pathologic correlation.

MATERIALS AND METHODS

Nine patients with surgically resected and pathologically confirmed sclerosing angiomatoid nodular transformation were included in the study. Clinical history was reviewed to determine patient demographics and symptoms at presentation. Gross pathologic, histologic, and immunohistochemical findings were recorded. CT (n = 9) and MRI (n = 4) examinations were evaluated for lesion shape and margins, intrinsic characteristics, and enhancement pattern.

RESULTS

Patients included were six women and three men, with a mean age of 41.2 years. Pathologic features of sclerosing angiomatoid nodular transformation included multiple angiomatous nodules in a radiating pattern with a central stellate fibrous scar and evidence of hemosiderin deposition. On imaging, the lesions were solitary and round, 78% having a lobulated margin. They were heterogeneously hypoenhancing during the arterial and portal venous phases of contrast-enhanced CT or MRI, with peripheral enhancing radiating lines in 88% of lesions. They showed progressive enhancement and were isoenhancing or hyperenhancing in the delayed phase. A hypoenhancing central scar was shown on imaging in 22% of lesions. All lesions were hypointense on T2-weighted images.

CONCLUSION

Sclerosing angiomatoid nodular transformation shows characteristic CT and MRI findings reflecting the underlying pathology. Typical features are a solitary, round, lobulated mass with early peripheral enhancing radiating lines and progressive enhancement of the angiomatous nodules; delayed enhancement of the fibrous tissue; and hypo-intense T2 signal intensity from hemosiderin deposition.

Sclerosing angiomatoid nodular transformation of the spleen: clinical and radiologic characteristics

BACKGROUND

Sclerosing angiomatoid nodular transformation (SANT) is a rare benign primary vascular lesion of the spleen. Although there have been many reports about the pathology of SANTs of the spleen, there have been no comprehensive descriptions of the imaging findings of SANTs of the spleen.

PURPOSE

To determine the clinical characteristics and imaging findings of SANTs of the spleen.

MATERIAL AND METHODS

We retrospectively evaluated seven patients with pathologically confirmed SANT, who underwent CT (n = 7), MRI (n = 4), ultrasonography (n = 4), and PET/CT (n = 3). Follow-up CT examinations were obtained in five patients. Clinical characteristics such as symptoms and concurrent disease were assessed. CT and MRI findings were evaluated by two radiologists, including the number, border, signal intensity, enhancement pattern, hemorrhage, and cystic change or necrosis. The longest diameter of each tumor was measured on CT. Echogenicity on ultrasonography and standardized uptake value on PET/CT were also evaluated.

RESULTS

No specific symptom was associated with SANT. Two patients had a history of malignancy, one with cervical cancer and the other with early gastric cancer. Tumor growth was observed in four of five patients. On CT, all seven SANTs appeared as single, well-demarcated masses. CT showed a heterogeneous enhancement in seven patients. MRI showed centripetal progressive enhancement and absence of cystic change or necrosis in four patients, with three of these patients showing evidence of old hemorrhage. Ultrasonography showed heterogeneous hypoechoic mass in four patients. PET/CT showed increased standardized uptake value, ranging from 2.0 to 2.8, in three patients.

CONCLUSION

SANT of the spleen is a single, well-demarcated solid mass without cystic change or necrosis. Increased FDG activity and tumor growth on follow-up imaging are common.

Sclerosing Angiomatoid Nodular Transformation (SANT) of the spleen: Case report and review of the literature

INTRODUCTION

Sclerosing Angiomatoid Nodular Transformation of the spleen (SANT) is a rare benign vascular lesion of the spleen with extensive sclerosis and unknown etiology.

PRESENTATION OF CASE

We report a new case of SANT of the spleen found in a 53-year-old female following detection of a splenic mass on a routine computed tomography (CT). The patient underwent an uncomplicated laparoscopic splenectomy and the specimen was sent for histopathologic examination.

DISCUSSION

A review of the 97 reported cases of SANT found in the literature was undertaken. There were 43 males and 54 females with a median age of 46 years (range: 11-82 years). SANT is classically considered to be a female predominant disease, however 44.3% of reported case were male and the gender predilection may soon be neutralized as more cases are reported. 65 of the 97 (67%) patients were in 30-60 year age group. The majority of lesions (n=50) were incidentally found on imaging, and for those patients presenting with symptoms, abdominal pain (n=18) was the predominant symptom.

CONCLUSION

The diagnosis of SANT should be considered in any patient presenting with a splenic lesion that contains an angiomatoid or inflammatory component. As the differential diagnosis for SANT includes malignant pathologies, and currently no reliable diagnostic radiological feature has been identified to differentiate between these conditions, SANT will continue to be diagnosed on the basis of surgical histopathology.

[Laparoscopic splenectomy for sclerosing angiomatoid nodular transformation]

Sclerosing angiomatoid nodular transformation (SANT) is a benign lesion of the spleen which can be cured by splenectomy. In the literature about 45 cases have been reviewed. Although it is defined by the morphological details, data regarding surgical therapy are scarce. To the best of our knowledge, a laparoscopic approach has not been published before. We investigated in one case of SANT the feasibility of a laparoscopic approach. Histological investigations confirmed the diagnosis of a SANT which was resected in toto. This report shows that the laparoscopic splenectomy is a feasible, safe and effective method for treatment of SANT.