Clinical History
A 70-year-old male patient presented with left anterior chest pain spreading to the abdomen after a recent minor trauma assessed with negative physical examination and chest X-rays and was discharged after excluding major complications. After some time, he came to the radiology department for CT follow-up of his known aortic aneurysm.
Imaging Findings
The scan demonstrated both a typical accessory spleen and a thin homogeneous parenchymal protuberance, inseparable from the splenic body and resembling a peduncle. From the caudal part of the spleen, it extended below up to the left iliac pit, running close to the left colon. The main splenic body and hilar vessels were located normally in their corresponding anatomic locus. We initially hypothesised that the symptoms reported by the patient may have been related to these CT findings and that, somehow, there might be a correlation with the recent traumatic injury. We then consulted the radiological archive of our institution in order to find any mention to the splenic anomaly detected. In a previous CT scan, performed 5 years before, the same splenic appearance was already recognisable but not mentioned. Therefore, we concluded that this finding was presumably asymptomatic (regardless of the trauma) and congenital.
Discussion
The spleen itself rarely represents the main diagnostic question for more advanced imaging studies (i.e. MDCT for focal lesions characterisation) and in daily routine practice its evaluation is generally included in a wide set of disorders. The first step of spleen assessment is generally represented by the evaluation of its morphology, also in relation to the potentially adjacent organs and structures (i.e. left hemidiaphragm, stomach, pancreatic tail, left kidney and corresponding adrenal gland and splenic flexure of the colon). The detection of morphologic variations is not surprising or uncommon, since incisions, bumps and lobes (expression of fetal residual) are not infrequently appreciable in adulthood. It is also a frequent incidental finding ("splenic incidentalomas"), generally with no clinical significance but potentially representing a differential diagnosis (i.e. intrapancreatic accessory spleen). [1] Among known anomalies, the most common one is the presence of accessory spleens (Figure 1), reported as an occasional finding in about 16% of patients undergoing a contrast-enhanced multidetector computed tomography (MDCT) scan of the abdomen [2] and often localised at the splenic hilum and contiguous to the organ. Sometimes polysplenia does not occur alone but coupled with other developmental abnormalities, such as intestinal malrotation, biliary atresia and situs viscerum inversus. [3] Not least, ectopic or migrants spleens can be found even in the pelvic cavity. The wandering or displaced spleen is a rare condition, often associated with childhood, typically not only due to embryological defects of the suspensory splenic ligaments (laxity or agenesis) but also secondary to trauma or splenomegaly.
To our knowledge, the morphologic variation described in this case has never been previously reported in the literature. The importance of diagnosing any morphological abnormality of the spleen, even in asymptomatic variants, is mainly related to those cases where a surgical intervention may be necessary. A careful diagnosis might also be essential in cases requiring a specific surgical management: the potential occurrence of torsion in presence of a wandering spleen (non-specific abdominal symptoms) [4-5] or bleeding originating from ectopic splenic tissue in cases of abdominal trauma. [6] Also in our case, regardless any potential relation with the above mentioned symptoms, the knowledge of the marked cranial-caudal extension of this splenic appendix and its close relationship with other left-sided organs and structures (Fig. 2, 3, 4 and 5) may furnish a comprehensive overview useful, as per any other anatomic variant, for patient management and history.
Differential Diagnosis List
Tubular spleen
Accessory spleen
Wandering spleen
