Selective Spleen Scintigraphy in the Evaluation of Accessory Spleen/Splenosis in Splenectomized/Nonsplenectomized Patients and the Contribution of SPECT Imaging

Are accessory spleen screening and resection in refractory immune cytopenia an effective strategy or a waste of resources?

Splenectomy remains an effective treatment for refractory immune cytopenia (RIC), which encompasses immune thrombocytopenia (ITP) and autoimmune hemolytic anemia (AIHA). Accessory spleens (AS) have been described without identifying specific risk factors. We retrospectively analyzed patients with RIC after splenectomy who underwent splenic scintigraphy (SS) at our institution. Seventy-one patients were included. Sixty-two patients had ITP, five had AIHA, and four had Evans syndrome. Seventy-five percent (n = 53) were women. Eleven patients (15.5%) had an AS detected by SS. A complete response (CR) to first-line steroids (odds ratio (OR) 5.75, 95% confidence interval (CI) 1.37-24.14, p = 0.017) and the absence of Howell-Jolly bodies (HJB) in peripheral blood smear (PBS) (OR 11.37, 95% CI 2.70-47.85, p = 0.001) were found to be risk factors. Patients with both elements had a higher rate of AS (83.3%) when compared to those with one or no factors (p < 0.001). Eight patients (73%) underwent an accessory splenectomy: seven (87.5%) achieved a CR, and none had perioperative complications. The presence of HJB in PBS changed from 25 to 87.5% after accessory splenectomy. We recommend the search for an AS via SS in patients with RIC due to ITP, who had a CR to corticosteroids and the absence of HJB in PBS. Accessory splenectomy is a safe and effective procedure.

PET/CT of the Spleen with Gallium-Oxine-Labeled, Heat-Damaged Red Blood Cells: Clinical Experience and Technical Aspects

Several scintigraphic techniques have been supplemented or replaced by PET/CT methods because of their superior sensitivity, high resolution, and absolute activity quantification capability. The purpose of this project was the development of a PET tracer for splenic imaging, its radiopharmaceutical validation, and its application in selected patients in whom unclear constellations of findings could not be resolved with established imaging methods. Heat-damaged red blood cells (RBCs) were labeled with [⁶⁸Ga]gallium-oxine, which was produced from [⁶⁸Ga]gallium and 8-Hydroxyquinoline (oxine) on an automated synthesizer. Ten patients underwent [⁶⁸Ga]gallium-oxine-RBC-PET/CT for the classification of eleven unclear lesions (3 intra-, 8 extrapancreatic). [⁶⁸Ga]gallium-oxine and [68Ga]gallium-oxine-labeled RBCs could be synthesized reproducibly and reliably. The products met GMP quality standards. The tracer showed high accumulation in splenic tissue. Of the 11 lesions evaluated by PET/CT, 3 were correctly classified as non-splenic, 6 as splenic, 1 as equivocal, and 1 lesion as a splenic hypoplasia. All lesions classified as non-splenic were malignant, and all lesions classified as splenic did not show malignant features during follow-up. PET/CT imaging of the spleen with [⁶⁸Ga]gallium-oxine-labeled, heat-damaged RBCs is feasible and allowed differentiation of splenic from non-splenic tissues, and the diagnosis of splenic anomalies.

High-Resolution Splenic Imaging: [68Ga]Ga-Oxine Red Blood Cell PET/CT for Differentiation of Splenosis Mimicking Malignant Lymphoma

The differentiation of splenic tissue from malignant lesions via imaging may be challenging, particularly considering aberrant or accessory lesions and diseases that are rarely encountered. Functioning splenic tissue can be identified using technetium-99m red blood cell (^99mTc-RBC) scintigraphy, but its sensitivity is limited and may not be available. We present the case of a patient in whom disseminated abdomino-pelvic splenosis was diagnosed using PET/CT with gallium-68-oxine-labeled RBCs. The method represents a feasible and probably superior alternative to splenic scintigraphy.

Multimodal study of pelvic splenosis: a rare cause of abdominal pain

We present a rare case of pelvic splenosis, in a 46-year-old man, with a previous history of partial splenectomy, complaining of nonspecific pain in the lower abdominal quadrants. Splenosis is a benign acquired condition, defined as a heterotopic autotransplantation of splenic tissue in other compartments of the body, caused by rupture of the splenic capsule following trauma or splenectomy. Splenosis is often asymptomatic and incidentally found and does not require treatment. Surgery is indicated only in patients presenting with symptoms or complications. In our case, the multimodal imaging study (ultrasound, MRI, CT, and scintigraphy) allowed a correct differential diagnosis without resorting to invasive procedures, susceptible to complications

Primary splenic lymphoma on top of intrahepatic splenosis: A unique case report

Solid organ splenosis is a challenging diagnosis with many atypical imaging features that can overlap with neoplastic masses of the affected organ. We present a sporadic case of intrahepatic splenosis in a 68-year-old woman with transformation into a low-grade B cell lymphoma. Initial cross-sectional imaging suggested focal nodular hyperplasia (FNH) ruled out on contrast-enhanced Magnetic Resonance Imaging (MRI) using a hepatobiliary-specific contrast agent. A Tc-99m sulfur colloid scan was negative. The final diagnosis was confirmed by a needle-guided biopsy revealing intrahepatic splenosis with transformation into a low-grade B cell lymphoma.

Subcutaneous Splenosis Presenting 37 years post-traumatic splenectomy; A Case Report

INTRODUCTION

The term splenosis refers to autotransplantation of splenic tissue in ectopic sites. Ectopic splenic tissue may be found in the liver, thorax, pelvis and subcutaneous tissues following traumatic splenectomy. Although clinically insignificant, local symptoms such as abdominal pain may arise. In this paper we report a case of subcutaneous splenosis presenting 37 years post-traumatic splenectomy.

CASE PRESENTATION

A 40-year-old medically free lady presented to our institution with a surgical history of post-traumatic splenectomy at the age of three and two cesarean sections. She complained for nonpainful right upper quadrant soft mass that has been stable in size over the years. Her laboratory results, including peripheral blood smear, were all within normal limits and no asplenic changes were detected. SPECT scan confirmed extraperitoneal splenosis in right upper quadrant.

DISCUSSION

Splenosis is an acquired form of ectopic splenic tissue that is defined as an auto-transplantation of a viable splenic tissue. It commonly occurs after traumatic rupture of the spleen.5 Splenosis has been widely reported around the world with an incidence of 16-67% after traumatic splenic rupture or splenectomy. Subcutaneous splenosis is an extremely rare condition, mostly observed in abdominal surgical scars. It is believed to follow laparotomy for splenectomy where splenic cells auto-implant or spread hematogenously at different locations.

CONCLUSION

Subcutaneous splenosis is a rare consequence of post-traumatic splenectomy that can manifest itself up to three decades after. Although concerning to the patient and alarming to the surgeon as it may resemble more serious entities such as abdominal wall sarcoma, surgical removal of asymptomatic splenosis is subject to the location of mass and patients' wishes.

Detection of Splenic Tissue Using 99mTc-Labelled Denatured Red Blood Cells Scintigraphy—A Quantitative Single Center Analysis

Background: Red blood cells (RBC) scintigraphy can be used not only for detection of bleeding sites, but also of spleen tissue. However, there is no established quantitative readout. Therefore, we investigated uptake in suspected splenic lesions in direct quantitative correlation to sites of physiologic uptake in order to objectify the readout. Methods: 20 patients with Tc-99m-labelled RBC scintigraphy and SPECT/low-dose CT for assessment of suspected splenic tissue were included. Lesions were rated as vital splenic or non-splenic tissue, and uptake and physiologic uptake of bone marrow, pancreas, and spleen were then quantified using a volume-of-interest based approach. Hepatic uptake served as a reference. Results: The median uptake ratio was significantly higher in splenic (2.82 (range, 0.58–24.10), n = 47) compared to other lesions (0.49 (0.01–0.83), n = 7), p < 0.001, and 5 lesions were newly discovered. The median pancreatic uptake was 0.09 (range 0.03–0.67), bone marrow 0.17 (0.03–0.45), and orthotopic spleen 14.45 (3.04–29.82). Compared to orthotopic spleens, the pancreas showed lowest uptake (0.09 vs. 14.45, p = 0.004). Based on pancreatic uptake we defined a cutoff (0.75) to distinguish splenic from other tissues. Conclusion: As the uptake in extra-splenic regions is invariably low compared to splenules, it can be used as comparator for evaluating suspected splenic tissues.

WFUMB Position Paper-Incidental Findings, How to Manage: Spleen

The World Federation for Ultrasound in Medicine and Biology (WFUMB) is addressing the issue of incidental findings (IFs) with a series of publications entitled "Incidental Imaging Findings-The Role of Medical Ultrasound." IFs are less commonly encountered in the spleen than in many other abdominal organs but remain a frequent dilemma in clinical practice. A histological diagnosis is rarely necessary for patient management. Many IFs, such as secondary spleens and splenic cysts, are harmless and do not require any further investigation. The diagnosis of many other focal splenic lesions is, however, often problematic. The following overview is intended to illustrate a variety of incidentally detected spleen pathologies such as size variants, shape variants, secondary spleens, focal splenic lesions and splenic calcifications. It should aid the examiner in establishing the diagnosis. Moreover, it should help the ultrasound practitioner decide which pathologies need no further investigation, those requiring interval imaging and cases in which immediate further diagnostic procedures are required.

SPECT/CT with 99mTc labelled heat-denatured erythrocyte to detect thoracic and abdominal splenosis

Scintigraphy with ^99mTc labelled heat-denatured erythrocyte (DRBC) allows non invasive diagnosis of heterotopic splenic tissue implantation (splenosis) following splenic trauma or surgery. Single-photon emission computed tomography (SPECT) combined with computed tomography (CT) improves diagnostic accuracy of planar imaging through a more precise localization of functional findings. We report about two cases of splenosis occurring many years after splenectomy. ^99MTc-DCRBC scintigraphy was used for differential diagnosis of metastatic disease in one case and to assess an incidental finding at bone scan in the second one. SPECT/CT increased specificity of planar imaging, expecially revealing combined (thoracic and abdominal) splenosis. (www.actabiomedica.it)

Intrapancreatic accessory spleen mimicking malignant tumor: three case reports

Intrapancreatic hypervascular lesions may represent metastases, neuroendocrine tumors, or intrapancreatic accessory spleens. The benign intrapancreatic accessory spleen can be difficult to separate from a malignant neuroendocrine tumor or metastasis. We report three cases of pancreatic lesions that underwent pancreatic surgery due to suspicion of malignancy on imaging; all cases were histologically intrapancreatic accessory spleens. Our cases point to the importance of performing single-photon emission computed tomography with heat-damaged Tc-99m-pertechnetate labelled erythrocytes to identify splenic tissue, even though small lesions can show a false-negative result.

Where is My Spleen? - A Case of Splenosis Diagnosed Years Later after Splenectomy

Hepatic splenosis was first described in 1939 and is a rare condition that results from splenic trauma or splenectomy.

A 43-year-old man with a past medical history significant for a prior splenectomy was admitted to the hospital due to right upper quadrant pain for two days. Magnetic resonance imaging (MRI) of the abdomen suggested features of hepatic adenoma, however, a percutaneous biopsy showed the mass within the liver to be a discrete collection of splenic tissue, apparently the result of a traumatic splenic rupture years ago.

Hepatic splenosis is a rare entity, and due to the asymptomatic nature of this condition, most cases are found incidentally after different imaging modalities are done. The management of this entity is based on conservative measures. We report this case to emphasize that in the appropriate clinical setting, hepatic splenosis should be considered in the differential diagnosis of a patient with a homogenous well-circumscribed liver mass.