Non-traumatic torsion of an accessory spleen as a cause of acute abdomen in adults

Introduction

An accessory spleen (AS) is a congenital anomaly of splenic tissue manifesting in nodules formed separately from the primary spleen [1–3]. Its prevalence varies and is estimated to be about 10–30%, depending on the study and group location, peaking in North America and Europe. In autopsies, it is over 10% [4]. In laparotomies, its prevalence is about 15% [5]. The AS can be the source of many complications, such as torsion, infarction, and cyst formation. In cases of injury, AS can also be the source of bleeding. AS can also migrate within the abdomen, causing recurrent pain by putting pressure on internal organs. An unusual location of AS can suggest a neoplasm as a differential diagnosis. However, a thorough histopathological exam can confirm the presence of splenic tissue. AS torsion is challenging to diagnose pre-operatively. Usually, when abdominal pain arises in the left hypochondriac region, the main suspicion is primary spleen pathology. It is rare for AS to be the primary source of symptoms. However, if some appropriate conditions, such as lack of fixation and ligaments, long vascular pedicle, and migration through the abdomen occur, torsion can be possible. AS torsion is more frequent in children [6]; thus, we would like to focus on adults as a less frequent anomaly. Torsion of an AS indeed can cause an acute abdomen. Acute abdomen is a condition that requires immediate attention and treatment and is potentially life-threatening [7].

Aim of the research

The aim of the study was to analyse the clinical course of the AS in terms of the symptoms it causes that require surgical intervention.
In the professional literature, reports can be found regarding symptoms caused by AS; however, these were only case reports. This prompted the authors to conduct a broader analysis of this clinical issue.

Material and methods

The material in the study comprised 24 cases of non-traumatic torsion of the AS in adults published between 2001 and 2024 (only complete cases, not abstracts). The material includes only articles from 2001 onward because this was the year when the first article that utilized diagnostic laparoscopy was published. The introduction of laparoscopic techniques marked a significant advancement in diagnosing and treating AS torsion. As a result, studies before 2001 did not incorporate this modern, minimally invasive approach, making them less relevant to the current understanding and management of the condition.
The desk research method was used, involving existing data described as individual cases by other researchers. The research was monographic, qualitative, and quantitative in nature, conducted in the form of a detailed description. Separate cases were obtained after searching the following Internet databases: PubMed, ClinicalKey, Academic Search Ultimate (EBSCO), BMJ Journals, Elsevier Journals, Embase, Karger, Oxford Journals, Scopus, Springer, and Wiley Online Library. Some articles were found by Google searches. All searches were performed between April and October 2024.
Each eligible case of AS torsion was entered into a case card; the data included patient age, sex, medical history, preoperative diagnosis and findings, treatment, pathology, size, and location of AS. The findings are presented in Table 1 [8–31].

Statistical analysis

The results were also subjected to statistical analysis, including the calculation of arithmetic means, standard deviations, medians, and minimum and maximum values.

Results

In total, 24 AS torsion cases were found, including 16 women and 8 men. The patients’ ages ranged from 19 to 47. The mean age was 27.1 ±7.7, and half of the subjects were no older than 24.5. In all cases, AS was found in the abdominal or pelvic cavity.
The most common symptom reported by patients was abdominal pain, which occurred in all patients (24 cases). The side of the pain was described in 20 (83.3%) cases: in 16 cases, the pain was predominantly on the left side (66.7%), and in 4 cases, on the right side (16.7%). Tenderness was reported in 16 (66.7%) cases. A palpable mass was described by 7 (29.2%) patients. Nausea or vomiting occurred in 7 (29.2%) patients.
The correct preoperative diagnosis (torsion of AS) was made in 8 cases (33.3% of cases). The key imaging studies for establishing the diagnosis before surgery were computed tomography (CT), magnetic resonance imaging (MRI), and Doppler ultrasound.
Other indications for surgical intervention included: abdominal mass/tumour; abdominal mass with twisted vascular pedicle; acute appendicitis; acute abdominal pain; peritoneal signs; ovarian or colonic neoplasm; splenic lymphangioma; gastrointestinal stromal tumour (GIST), tumours originating from the omentum, hemorrhagic infarction due to torsion, an organized hematoma.
In all cases of AS torsion, surgical treatment was performed with splenectomy of AS by laparotomy (15 cases; 62.5% of cases) and by laparoscopy (9 cases; 37.5% of cases).
No mortality has been reported.

Discussion

The accessory spleen usually gains clinical significance in cases of total splenectomies (including primary and accessory spleens) for haematological diseases or immune thrombocytopenic purpura (ITP). Incomplete resection of splenic tissue may result in the need for reoperation [32, 33]. AS also plays a crucial role when detected during radiological procedures. Accessory spleens may be detected incidentally and must be carefully distinguished from conditions such as splenosis, neoplasms, or lymphadenopathy. When the pain in the abdomen occurs, AS can also be a possible cause. Usually, AS is asymptomatic. In certain conditions, such as torsion, rupture, enlargement of AS, and haemorrhage, AS may produce symptoms [34]. Usually, when AS becomes symptomatic, the symptoms are not specific. They may be associated with location, such as pain in the left upper quadrant of the abdomen. Still, AS can also wander through/migrate within the abdomen, for example, mimicking acute appendicitis [35]. The differential diagnosis of AS torsion should include a broad spectrum of abdominal diseases. The symptoms of AS torsion (abdominal pain, tenderness, palpable mass, nausea, vomiting) are very similar to those described in primary spleen torsion [36]. The complaints reported by the patient may also resemble subserosal torsion of uterine myoma [37, 38]. The most prevalent locations of AS are the splenic hilum, the tail of the pancreas, gastrosplenic and lienorenal ligaments, the greater omentum, the mesentery [34, 39]. AS can also be located in the pelvis [40] and the thorax [41].
Torsion of AS is a rare condition but can be the cause of acute abdomen. As it manifests in a nonspecific manner, just like the torsion of a primary spleen, it often requires imaging diagnostics to be diagnosed [42]. Depending on the availability and stability of the patient, it is usually determined through USG, CT, or MRI. The condition manifests as a lack of flow through Doppler USG. If the patient is stable, 99mTc-denatured RBC scans can be helpful in identifying the AS [3, 43]. However, in cases of hemodynamical instability caused by internal bleeding, the diagnosis is made during emergency surgery. The laparoscopic/robotic/minimally invasive surgery seems to be a proper approach. However, it may not be attainable in cases of extensive abdominal masses. Thus, laparotomy is always an applicable approach.

Conclusions

AS torsion is a rare condition. Almost all of the cases involved individuals aged up to 40. AS torsion should always be considered a possible cause of acute abdomen of unknown aetiology, especially in young adults, who were dominant in our study. The symptoms of AS torsion do not differ from those of the primary spleen torsion. The AS may be misdiagnosed as an abdominal neoplasm of nearby affected organs, especially when it is asymptomatic. Nevertheless, if acute abdomen symptoms occur, AS should always be excised. Preoperative identification of an AS or the absence of a primary spleen facilitates patient management and shortens the duration of surgery.

Funding

The publication fee was financed by the Department of Biomedicine and Experimental Surgery, Medical University of Lodz.

Ethical approval

Not applicable.

Conflict of interest

The authors declare no conflict of interest.

References