Polyclonality in Sclerosing Angiomatoid Nodular Transformation of the Spleen

Fifth Edition of the World Health Organization Classification of Tumors of the Hematopoietic and Lymphoid Tissues: Mature T-Cell, NK-Cell, and Stroma-Derived Neoplasms of Lymphoid Tissues

This review focuses on mature T cells, natural killer (NK) cells, and stroma-derived neoplasms in the fifth edition of the World Health Organization classification of hematolymphoid tumors, including changes from the revised fourth edition. Overall, information has expanded, primarily due to advancements in genomic understanding. The updated classification adopts a hierarchical format. The updated classification relies on a multidisciplinary approach, incorporating insights from a diverse group of pathologists, clinicians, and geneticists. Indolent NK-cell lymphoproliferative disorder of the gastrointestinal tract, Epstein-Barr virus-positive nodal T- and NK-cell lymphoma, and several stroma-derived neoplasms of lymphoid tissues have been newly introduced or included. The review also provides guidance on how the fifth edition of the World Health Organization classification of hematolymphoid tumors can be applied in routine clinical practice.

Stroma-derived neoplasms and pseudoneoplastic lesions of the spleen: a select review of pathologic and CT/MRI findings

A wide spectrum of benign and malignant primary mesenchymal tumors and tumor-like lesions of the spleen has been recently included under the umbrella term 'stroma-derived' neoplasms and tumor-like lesions. These include dendritic cell neoplasms such as follicular dendritic cell sarcoma, EBV-positive inflammatory follicular dendritic cell sarcoma, and fibroblastic reticular cell tumor; smooth muscle and myofibroblastic lesions such as inflammatory pseudotumor, EBV-associated smooth muscle tumor and undifferentiated pleomorphic sarcoma as well as a diverse spectrum of vascular and vascular-stromal tumors and tumor-like lesions. While some tumor and tumor-like lesions are unique to the spleen, others may also occur in diverse extra-splenic viscera. These tumors and tumor-like lesions demonstrate characteristic histopathology, immunocytochemistry and biological behavior. While cross-sectional imaging studies allow detection, staging and limited characterization of these splenic lesions, histopathological confirmation permits optimal management and surveillance strategies.

What is new in the 5th edition of the World Health Organization classification of mature B and T/NK cell tumors and stromal neoplasms?

The classification of tumors is essential in the diagnosis and clinical management of patients with malignant neoplasms. The World Health Organization (WHO) provides a globally applicable classification scheme of neoplasms and it was updated several times. In this review, we briefly outline the cornerstones of the upcoming 5th edition of the World Health Organization Classification of Haematolymphoid Tumours on lymphoid neoplasms. As is adopted throughout the 5th edition of the WHO classification of tumors of all organ systems, entities are listed by a hierarchical system. For the first time, tumor-like lesions have been included in the classification, and modifications of nomenclature for some entities, revisions of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities are presented along with mesenchymal lesions specific to the stroma of lymph nodes and the spleen. In addition to specific outlines on constitutional and somatic genetic changes associated with given entities, a separate chapter on germline predisposition syndromes related to hematologic neoplasms has been added.

Laparoscopic splenectomy for sclerosing angiomatoid nodular transformation of the spleen: Report a case

INTRODUCTION AND IMPORTANCE

Sclerosing angiomatoid nodular transformation (SANT) of the spleen is an extremely rare benign lesion.

CASE PRESENTATION

Here, we describe the case of a 52-year-woman who was diagnosed with sclerosing angiomatoid nodular transformation of the spleen. Abdominal contrast-enhanced CT revealed a solid lesion in the splenic hilum that was slowly enhanced between the portal venous and equilibrium phases incidentally. Fluorodeoxyglucose positron emission tomography (FDG-PET) revealed FDG accumulation within the mass, with a maximum standardized uptake value (SUVmax) of 2.57. Based on these findings, the patient was scheduled for laparoscopic splenectomy. The total operating time was 193 min, and the intraoperative blood loss was 20 ml. The resected specimen was 9.0 × 8.4 × 5.6 cm and dark brown in colour with a large central stellate fibrotic scar.

CLINICAL DISCUSSION

Pathological examination revealed nodular angioma lesions and the proliferation of fibrotic interstices and inflammatory cells. We could diagnose the SANT by the only HE staining without Immunohistochemical staining.

CONCLUSION

Although SANT is a rare benign lesion, which is difficult to definitively diagnose based on preoperative imaging findings alone, it should be considered in cases of solitary splenic lesions, and we recommend performing LS and subsequent histological examination for the diagnosis of this disease.

A case of multifocal sclerosis angiomatoid nodular transformations of the spleen occurring after partial splenic infarction with transcatheter arterial embolization for splenic artery aneurysm

A 48-year-old woman underwent transcatheter arterial embolization (TAE) for a splenic artery aneurysm, which resulted in a partial splenic infarction in the middle lobe. Five years after TAE, a 20-mm diameter mass in the noninfarcted area of the spleen was detected on imaging, which grew to 25 mm in diameter after 6 months. MRI after gadolinium administration showed a 35 × 34 mm mass within the superior pole and 15 × 12 mm mass within the inferior pole. The patient underwent laparoscopic splenectomy and had an uneventful postoperative recovery. No evidence of recurrence was observed during the 2-year follow-up period after surgery. The mass was pathologically confirmed to be sclerosing angiomatoid nodular transformation (SANT) of the spleen. While some studies hypothesize that SANT is a response to vascular injury or trauma, to the best of our knowledge, there have been no previous reports of SANT occurring after procedures directly affecting splenic blood flow. Additionally, multifocal SANTs are reported to be very rare, accounting for only 4.7% of all reported SANTs of the spleen. We highlight a rare course of SANT of the spleen and discuss the possible relationship between blood flow abnormalities and the appearance of SANT.

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.

Lymph Nodes With Increased IgG4-positive Plasma Cells and Patterns Suspicious for IgG4-related Disease: Can Lymph Nodes Be the Only Site of Disease?

Lymphadenopathy with increased immunoglobulin (Ig) G4 + plasma cells can be a nonspecific finding or a manifestation of immunoglobulin G4-related disease (IgG4-RD). It remains unclear whether there are characteristic pathologic features of IgG4-RD involving lymph nodes, or if IgG4-RD lymphadenopathy can occur without other manifestations of IgG4-RD. In this study, we assessed 55 lymph node biopsy specimens (44 men and 11 women with a mean age of 55 y) with increased IgG4 + plasma cells that had 1 of the 6 well-described pathologic patterns. We also correlated these findings with IgG4 serum levels and followed these patients for 7 to 108 months (mean, 34.9 mo) for the occurrence of extranodal IgG4-RD. We further compared lymphadenopathy in patients who developed other manifestations of IgG4-RD (RD + , n=20, 36%) versus those who did not (RD - , n=35, 64%). We found that there were only minor significant differences between 2 groups, including frequency of receiving treatment (RD + , 90% vs. RD - , 60%, P =0.021) and higher serum levels of C-reactive protein (>8 mg/L, RD + , 53% vs. RD - , 13%, P =0.007). Other differences were either borderline or not significant, including mean age (RD + , 59.8 y vs. RD - , 51.9 y, P =0.097), male-to-female ratio (RD + , 16:4 vs. RD - , 28:7, P =1), constitutional symptoms (RD + , 25% vs. RD - , 9%, P =0.096), multiple enlarged lymph nodes (RD + , 45% vs. RD - , 26%, P =0.143), good response to therapy (RD + , 94% vs. RD - , 94%, P =1); higher serum IgG4 levels (>280 mg/dL, RD + , 75% vs. RD - , 51%, P =0.086), anemia (RD + , 45% vs. RD - , 43%, P =0.877), leukopenia (RD + , 0% vs. RD - , 3%, P =0.446), thrombocytopenia (RD + , 10% vs. RD - , 6%, P =0.556), positivity for antinuclear antibody (RD + , 24% vs. RD - , 29%, P =0.688), elevated serum levels of lactate dehydrogenase (>225 U/L, RD + , 0% vs. RD - , 20%, P =0.064), elevated serum IgE level (>100 IU/mL, RD + , 75% vs. RD - , 92%, P =0.238), and hypergammaglobulinemia (RD + , 90% vs. RD - , 86%, P =0.754). There were also no differences in morphologic patterns ( P =0.466), IgG4 + cell location ( P =0.104), eosinophil counts (RD + , 10.3±11.3 vs. RD - , 13.4±17.5, P =0.496), Epstein-Barr virus positivity (RD + , 35% vs. RD - , 60%, P =0.074), and Epstein-Barr virus-positive cell location ( P =0.351). Our findings suggest that there are minimal differences between stringently defined IgG4-RD lymphadenopathy with versus without other manifestations of IgG4-RD. These findings also suggest the existence of IgG4-RD lymphadenopathy as the sole presentation of IgG4-RD.

Sclerosing angiomatoid nodular transformation of the spleen: a case report

Sclerosing angiomatoid nodular transformation (SANT) of the spleen is an uncommon primary benign condition with specific histopathological characteristics. The majority of the patients are usually asymptomatic and present for treatment after an incidental finding on a routine abdominal imaging. The differential diagnosis includes other benign tumours, as well as primary malignancy or metastases of unknown origin. We report a 55-year-old woman who was presented to the surgical team of our hospital for splenectomy after the investigation of an incidental splenic lesion led to the diagnosis of SANT. The pathology report of the specimen repeated the initial diagnosis. The patient has not yet presented any complication or recurrence of the disease 8 months after the operation. From such infrequent cases, the most valuable conclusion which can be yielded is that the more the number of patients reported, the more the knowledge about the disease is broadened.

Morphologic Spectrum of Lymphadenopathy in Adult-onset Immunodeficiency (Anti-interferon-γ Autoantibodies)

Adult-onset immunodeficiency syndrome (AOIS) caused by anti-interferon-γ autoantibodies is an emerging disease. Affected patients present typically with systemic lymphadenopathy, fatigue, and fever. We studied 36 biopsy specimens, 31 lymph nodes, and 5 extranodal sites, of AOIS confirmed by serum autoantibody or QuantiFERON-TB Gold In-Tube assay. We describe the morphologic features and the results of ancillary studies, including special stains, immunohistochemistry, and molecular testing. The overall median age of these patients was 60.5 years (range, 41 to 83 y) with a male-to-female ratio of 20:16. All biopsy specimens showed nontuberculous mycobacterial infection, and most cases showed the following histologic features: capsular thickening with intranodal sclerosing fibrosis, irregularly distributed ill-formed granulomas or histiocytic aggregates with neutrophilic infiltration, interfollicular expansion by a polymorphic infiltrate with some Hodgkin-like cells that commonly effaces most of the nodal architecture and proliferation of high endothelial venules. In situ hybridization analysis for Epstein-Barr virus-encoded RNA showed scattered (<1%) to relatively more common (4% to 5%) positive cells in 29 of 30 (97%) tested specimens, reflecting immune dysregulation due to an interferon-γ defect. In the 31 lymph node specimens, 23 (74%) cases showed increased immunoglobulin G4-positive plasma cells (4 to 145/HPF; mean, 49.7/HPF) with focal areas of sclerosis reminiscent of immunoglobulin G4-related lymphadenopathy, 4 (13%) cases resembled, in part, nodular sclerosis Hodgkin lymphoma, and 9 (29%) cases mimicked T-cell lymphoma. Among 33 patients with available clinical follow-up, 20 (61%) showed persistent or refractory disease despite antimycobacterial therapy, and 1 patient died of the disease. We conclude that the presence of ill-defined granulomas, clusters of neutrophils adjacent to the histiocytic aggregates, and some Epstein-Barr virus-positive cells are features highly suggestive of AOIS. A high index of clinical suspicion and awareness of the morphologic features and differential diagnosis of AOIS are helpful for establishing the diagnosis.

Loss of CTNNB1 exon 3 in sclerosing angiomatoid nodular transformation of the spleen

Sclerosing angiomatoid nodular transformation (SANT) is a rare vascular lesion of the spleen. Although several hypotheses have been suggested, the etiopathogenesis of SANT remains unknown. It is also unclear whether SANT is a reactive or a neoplastic lesion. Since CTNNB1 (β-catenin gene) exon 3 mutations were frequently detected in some rare fibrovascular lesions, we aimed to investigate the presence of oncogenic CTNNB1 mutations in SANT cases. For this purpose, 7 cases of SANT with typical histopathological features were retrieved. First, the presence of CTNNB1 exon 3 alterations was examined with a recently described immunohistochemistry-based method. Then, the findings were confirmed with polymerase chain reaction (PCR), reverse transcription PCR (RT-PCR), and Sanger sequencing. In all cases, immunochemistry of β-catenin gave a staining pattern that was suggestive of exon 3 alteration; however, no missense mutations were found in any case at the CTNNB1 exon 3 hotspot region. Subsequently, we screened for large interstitial deletions of CTNNB1 exon 3 which revealed short PCR products in three cases. Sequencing confirmed that these cases had large interstitial deletions, resulting in loss of the entire exon 3 of CTNNB1. In the remaining four cases, loss of exon 3 was documented at the cDNA level, although genomic deletion was not identified. These results demonstrate that loss of CTNNB1 exon 3 and stabilization of β-catenin with activation of Wnt signaling pathway might have a significant role in the pathogenesis of SANT. Through this study, we provided important evidence for the neoplastic nature and pathogenesis of this disorder.

Sclerosing Angiomatoid Nodular Transformation of the Spleen: Analysis of Clinical and Pathological Features in Five Cases

Objective: We aimed to summarize the clinical and pathological features of sclerosing angiomatoid nodular transformation (SANT) in spleen among five cases.

Methods: Five cases (male: 3; female: 2; mean age: 47.6 years) with SANT confirmed by pathological analysis between July 2010 and November 2019 in our hospital were included in this study. The clinical, imaging, and pathological data were analyzed retrospectively.

Results: Three patients presented with mild abdominal pain or discomfort, while the other two were symptom free. Two patients received ultrasonography (US), and all patients underwent a computerized tomography (CT) scan in our hospital. The typical “spoke wheel” pattern was seen in two cases, and central calcification was detected in one case on the CT scans. All patients indicated peripheral enhancement around the SANT lesion during the arterial phase. Open or laparoscopic splenectomy was performed for treatment. No patient showed recurrence in the follow-up. The pathological characteristics of our cases were in line with those of previous literatures.

Conclusions: Peripheral enhancement around the SANT lesion during the arterial phase should be taken into consideration for the diagnosis of SANT as an imaging sign on CT scans. Special attention should be paid to the splenic integrality during the laparoscopic approach, due to the probability of malignancy and the fragility of the spleen.

Treatment options for sclerosing angiomatoid nodular transformation of spleen

BACKGROUND

To summarise the clinical features of Sclerosing angiomatoid nodular transformation (SANT) of the spleen and to compare the efficacy of three different surgical treatments.

METHODS

We performed a retrospective analysis of patients with SANT of spleen treated at our center from 2009 to 2018. We compared the efficacy and safety of three different types of surgical procedures. ANOVA and the chi-square test were used for statistical analysis.

RESULTS

A total of 37 patients were included. Most (35/37; 94.6%) were asymptomatic. A number presented as obscure boundary lesions such that malignancy could not be excluded. Open splenectomy was performed for 12 patients, laparoscopic splenectomy for 12 patients and laparoscopic partial splenectomy for 13 patients. Operation time (P = 0.355), blood loss (P = 0.135), length of hospital stay after operation (P = 0.271) and postoperative complications (P = 0.502) were comparable between the three groups. Duration of drainage tube placement was significantly longer in laparoscopic partial splenectomy patients (P = 0.006). Peak platelet count after operation was significantly lower in laparoscopic partial splenectomy patients (P < 0.001).

CONCLUSION

Laparoscopic partial splenectomy appears to be a technically feasible and therapeutically effective approach for SANT.

A sclerosing angiomatoid nodular transformation (SANT) mimicking a metachronous splenic metastasis from endometrioid cancer and ovarian cancer

INTRODUCTION

Sclerosing angiomatoid nodular transformation (SANT) of the spleen has been considered a differential diagnosis of splenic lesions since it was originally reported. However, preoperative diagnosis of SANT is often difficult and histopathological examination by surgical resection is required.

CASE PRESENTATION

Because of a new splenic lesion, a 48-year-old woman was suspected of having metachronous solitary splenic metastasis during her postoperative follow-up for endometrioid and ovarian cancer that occurred 3 years previously. Because there was no metastasis to other sites, laparoscopic splenectomy was successfully performed for diagnosis and treatment. Histopathological examination revealed that the splenic lesion consisted of three distinct splenic vessels, thereby indicating SANT without any cancer cells or lymphoproliferative disorders.

CONCLUSION

Splenectomy should be considered for the diagnosis and treatment of incidentally detected splenic lesions during follow-up for malignancy.

Sclerosing Angiomatoid Nodular Transformation of the Spleen: Lessons from a Rare Case and Review of the Literature

Sclerosing angiomatoid nodular transformation (SANT) of the spleen is an extremely rare benign lesion. We herein report a case of asymptomatic SANT of the spleen in a middle-aged woman with early breast carcinoma and an undiagnosed splenic mass, which was successfully treated by laparoscopic splenectomy and diagnosed postoperatively. We also review the literature on SANT to help make knowledge more accessible when clinicians encounter a splenic tumor. The present case taught us the following lesson: the presence of a splenic lesion during follow-up for malignancy is not always indicative of metastasis. Therefore, SANT should be considered in the differential diagnosis.

Sclerosing angiomatoid nodular transformation in the spleen: A case series study and literature review

To assess the clinicopathologic features, differential diagnosis, and pathogenesis of sclerosing angiomatoid nodular transformation (SANT) of the spleen.The clinical characteristics of 7 cases with SANT were retrospectively analyzed. Histochemical and immunohistochemical (EnVision method) examinations were performed. Moreover, quantitative assessment of IgG4 and IgG-positive cells was performed.The 7 SANT patients included 1 female and 6 males, with ages ranging from 7 to 60 years (mean 33.4 years). They showed no specific clinical manifestations. Macroscopically, the surface of the excised masses was gray-white, and vague nodularity was observed. Mass sizes ranged from 3.0 to 7.0 cm (mean 5.5 cm). Microscopically, all cases were characterized based on multiple angiomatoid nodules of various sizes embedded in a fibrosclerotic stroma. The nodules were round and sometimes convoluted. Moreover, the nodules were composed of slit-like, irregularly-shaped, or slightly dilated vascular spaces lined by plump endothelial cells, and interspersed with a population of spindly or ovoid cells. Immunohistochemical examination showed a heterogeneous staining pattern, with the lining cells of small capillaries expressing CD34 and those of sinusoid-like structures expressing CD8. CD31 was stained in the lining and interspersed cells, thus resulting in a complex meshwork. Additionally, the lining cells were focally positive for CD68. Vimentin and smooth muscle antibody were expressed in all 7 cases, whereas no desmin or CD21 was detected. IgG4-positive cells accounted for 2 to 5 per high-power field (mean 3.7). Furthermore, the IgG-positive cells accounted for 2 to 8 per high-power field (mean 4.2).SANT is a rare primary benign tumor-like lesion of the spleen, and has characteristic histopathological features and immunohistochemical profiles. SANT should be distinguished from other angiomatoid tumors and tumor-like lesions. Moreover, SANT could be treated by splenectomy, with favorable prognosis. The relationship between SANT and IgG4-related sclerosing lesions remains to be clarified.

Sclerosing angiomatoid nodular transformation (SANT) of spleen mimicking a splenic abscess: Case report and review of the literature

INTRODUCTION

SANT of the spleen is a benign lesion that does not recur after splenectomy with unknown etiology.

PRESENTATION OF THE CASE

We report a case of sclerosing angiomatoid nodular transformation (SANT) of the spleen mimicking a splenic abscess in a patient with imaging studies that failed to differentiate this lesion from other splenic lesions.

DISCUSSION

SANT of the spleen is a rare condition, with only less than 100 cases reported in the literature. Clinically, SANT is only a kind of described pathological diagnostic conception. As in our case, these splenic lesions are often incidental findings on imaging studies performed for other reasons.

CONCLUSION

The patient was treated with splenectomy, which has proved to be both diagnostic and therapeutic. Although histology can lead to the diagnosis of vascular tumor, immunohistochemistry is the only way to confirm the diagnosis.

Sclerosing angiomatoid nodular transformation of the spleen (SANT) in a patient with clear cell carcinoma of the uterus: a case report

Background

Sclerosing angiomatoid nodular transformation of the spleen is a very rare benign vascular lesion recently described. Usually, sclerosing angiomatoid nodular transformation of the spleen is an incidental finding; the association with malignant tumors is extremely rare. To the best of our knowledge, we report the first case of sclerosing angiomatoid nodular transformation of the spleen associated with uterine clear cell carcinoma.

Case presentation

A 49-year-old Arabic woman presented to our institute with abdominal pain and distention. An abdominal computed tomographic scan was obtained, which showed a 14-cm uterine malignant tumor and a 4-cm isolated splenic nodule suggesting a metastatic lesion. The tumor was limited to the uterus but did not extend beyond. The patient underwent surgical treatment, and the histopathological examination of the resected uterine and splenic specimens disclosed invasive uterine clear cell carcinoma and sclerosing angiomatoid nodular transformation of the spleen, respectively. The patient had no signs of the disease 17 months after surgical treatment.

Conclusions

Sclerosing angiomatoid nodular transformation of the spleen is a very rare benign disease with a misleading presentation when associated with a malignant tumor. Pathological assessment of the resected spleen is the only way to achieve the correct diagnosis.

Sclerosing angiomatoid nodular transformation of the accessory spleen: A case report and review of literature

RATIONALE

Sclerosing angiomatoid nodular transformation (SANT) is a rare case which usually occurs in spleen, but our case occurs in accessory spleen.

PATIENT CONCERNS

We reported a case of a 27 year old man who was identified with an isodense mass in the left abdominal cavity by ultrasonicphysical examination without symptoms. Blood routine and tumor markers (alpha fetal protein, carcinoembryonic antigen, CA19-9, CA125) were normal.

DIAGNOSES

The tumor was firstly diagnosed as left abdominal mass and its origin was considered as small intestinal by the radiologist. The pathological diagnosis was the sclerosing angiomatoid nodular transformation (SANT) of the accessory spleen.

INTERVENTIONS

Laparoscopic splenectomy is a more reliable method for the treatment of SANT.

OUTCOMES

Non-enhanced CT showed iso-intensity lesion of the accessory spleen, and enhanced CT showed progressive enhancement. According to the above characteristics, we should consider the diagnosis of spleen SANT. We reviewed some literatures to summarize the characteristics of SANT.