Imaging Pearls ❯ Spleen ❯ Normal Spleen
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- “Wandering spleen refers to a spleen located in the abdominal cavity other than the typical location in the LUQ as usual. It is a very rare anomaly, with an incidence of less than 0.5% . This anomaly is usually found in children or in women between 20–40 years of age. Normally, the position of the spleen is fixed by the gastrosplenic and splenorenal ligaments. Wandering spleen is thought to be caused by laxity or maldevelopment of the splenic ligaments. Most patients with wandering spleen do not have symptoms. However, splenic torsion owing to increased spleen mobility can lead to splenic infarction and congestion, which may cause mild discomfort or acute abdominal pain. On CT of this condition, the spleen is not visible in the LUQ but is instead detected in the central abdomen or pelvic cavity. Sometimes, splenic vessels are elongated from the LUQ and lead to the spleen. When torsion is accompanied, splenic pedicles containing splenic vessels and surrounding fat tissue show a “whirlpool” appearance with decreased blood flow in part or all of the spleen.”
Various congenital anomalies and anatomical variations of the spleen: a multimodality pictorial review
Young Sil Jang1 et al.
Abdominal Radiology (2023) 48:1505–1513 - “Hemangioma is the most common benign tumor of the spleen, with the cavernous type being the most common. Splenic hemangiomas are mostly discovered incidentally without showing overt symptoms. Most lesions are less than 2 cm in diameter, but, when larger, spontaneous rupture can occur, which has been reported in approximately 25% of patients with splenic hemangioma. Splenic hemangioma is thought to be a congenital disorder that arises from the endothelium of blood sinusoids in splenic red pulp.”
Various congenital anomalies and anatomical variations of the spleen: a multimodality pictorial review
Young Sil Jang1 et al.
Abdominal Radiology (2023) 48:1505–1513
- Normal Variant Anatomy of the Spleen (1)
- Splenic cleft and lobulation
--- The cleft on the superior border are remnants of the groves that originally separated the fetal lobules, and can simulate lacerations.
- Accessory spleen
--- Found in 10-20% of individuals.
--- Within the tail of the pancreas is the second common site of the accessory spleen, and can mimic hypervascular pancreatic tumor (e.g. neuroendocrine tumor)
--- Accessory spleen can be a site of relapse of hypersplenism after splenectomy in patients with a hematologic disorder with hypersplenism. - Normal Variant Anatomy of the Spleen
- Accessory spleen
--- Found in 10-20% of individuals.
--- Within the tail of the pancreas is the second common site of the accessory spleen, and can mimic hypervascular pancreatic tumor (e.g. neuroendocrine tumor)
--- Accessory spleen can be a site of relapse of hypersplenism after splenectomy in patients with a hematologic disorder with hypersplenism.
- Splenosis
--- Ectopic splenic tissue caused by autotransplantation of splenic cells resulting from traumatic disruption of the splenic capsule via trauma or surgery.
--- More numerous and widespread than accessory spleens. - Normal Variant Anatomy of the Spleen
- Polysplenia
--- A rare complex syndrome, consists of situs ambiguous with features of left isomerism (bilateral left-sidedness)
--- Multiple spleen in right or left upper quadrant, single, lobulated spleen, or a normal spleen
--- Anomalous position of abdominal viscera, short pancreas, abnormal bowel rotation, cardiovascular anomalies
- Asplenia
--- Absent spleen, situs ambiguous, multiple anomalies including cardiovascular anomalies (typically more complex than those with polysplenia), bowel malrotation, genitourinary tract anomalies. - Normal Variant Anatomy of the Spleen
- Wandering spleen
--- The spleen migrate from its normal position due to congenital or acquired laxity of the splenic suspensory ligament.
--- At risk of vascular pedicle torsion and splenic infarct.
- What is a normal spleen?
- Splenic size varies depending on age, nutrition and patient size.
normal: 12 x 4 x 7 cm
- Splenic Volume
AP x transverse x superior-inferior / 2.
normal: < 150 g - Normal Spleen: Facts
Accessory spleens are common
- failure of fusion, usually near hilum
- usually < 3 cm, round, enhance like spleen
- don’t mistake accessory spleens for nodes
Lobulations are very common
- clefts cause lobulations
- don’t mistake clefts for lacerations or infarcts - "Multidetector row CT volumetrics and anatomic evaluation provided accurate and reproducible information."
Laparoscopic Splenectomy: Multidetector Row CT for Preoperative Evaluation
Napoli A et al.
Radiology 2004; 232:361-367 - "Complete vascular mapping of the spleen is now feasible because of the technical advances in multidetector row technology with isotrophic data acquisition and high resolution post processing imaging display."
Laparoscopic Splenectomy: Multidetector Row CT for Preoperative Evaluation
Napoli A et al.
Radiology 2004; 232:361-367 - Splenic Arterial Anatomy: Facts
- The average number of branches to the spleen originating 3-13 cm from the hilum is between 6 and 12 as is called a distributed pattern.
- A magistral type of branching consists of a long splenic artery that divides near the hilum into 3 or 4 large short terminal branches