A Splenic IgG4+ Sclerosing Angiomatoid Nodular Transformation (SANT) Treated by Hemisplenectomy: A Radiologic, Histochemical, and Immunohistochemical Study

Sclerosing Angiomatoid Nodular Transformation of the Spleen in a Patient With Granulomatosis With Polyangiitis

We present an intriguing case involving a rare occurrence of sclerosing angiomatoid nodular transformation (SANT) in a 57-year-old woman with a history of granulomatosis with polyangiitis (GPA). Despite the extensive literature on SANT, its pathogenesis remains elusive. The patient, diagnosed with serum anti-proteinase 3 antineutrophil cytoplasmic antibody (PR3-ANCA)-positive GPA seven years earlier, exhibited a splenic lesion during imaging, leading to laparoscopic splenectomy due to severe abdominal pain. Microscopic analysis unveiled nodular structures with vascular elements surrounded by fibrosclerotic stroma and chronic inflammatory cells. This case raises questions about the interplay between SANT, GPA activity, and vascular damage. Hypotheses regarding SANT's origin, including its potential association with organized hematoma or alterations in splenic blood flow, are discussed. The uniqueness of this case lies in the coexistence of PR3-ANCA-positive GPA and SANT, suggesting a potential link between GPA activity, vascular damage, and SANT development. While causality remains uncertain, this report marks the first documented case of a patient with PR3-ANCA-positive GPA developing SANT. The findings prompt reflection on a potential common pathophysiological mechanism and underscore the importance of considering SANT in cases of splenic lesions associated with conditions causing alterations in splenic blood flow. This contribution serves as a valuable addition to the existing knowledge, urging further research and consideration of SANT in diagnostic scenarios involving splenic abnormalities.

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.

•

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

•

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

•

Laparoscopic splenectomy is curative treatment for SANT.