Spleen Flashcards
- A 64-year-old man with known sigmoid adenocarcinoma diagnosed at endoscopy undergoes staging CT. A solitary, well-defined, rounded, homogeneous, 1 cm mass of mean attenuation value identical to the spleen is seen near the splenic hilum. What is the most likely diagnosis?
A. metastatic lymph node
B. wandering spleen
C. splenic artery aneurysm
D. polysplenia
E. accessory spleen
E. accessory spleen
Accessory spleen (splenunculus) is seen in 10–30% of the population and results fromdevelopmental failure of fusion of the mesodermal buds that form the spleen. Theyappear as small (usually <10 mm), well-defined masses with identical attenuation andenhancement characteristics as the spleen, and are most commonly located near thesplenic hilum.
Following splenectomy for haematological disorders, an accessory spleenmay undergo hypertrophy and result in recurrence of the original disorder.
Regional lymph nodes from colorectal cancer extend along the course of the main vessels supplying the segment of bowel.
Wandering spleen refers to a normal spleen positionedin an abnormal location within the abdomen due to laxity of the splenic ligaments.
Splenic artery aneurysms are focal dilatations of the splenic artery, which may be intra or extra splenic and are frequently calcified.
Polysplenia is a rare congenital disorderassociated with situs ambiguous, and characterized by multiple small spleens usually inthe right abdomen.
- A 45-year-old woman with pleuritic chest pain and breathlessness undergoes CT pulmonary angiogram for suspected acute pulmonary embolism, which demonstrates multiple irregular areas of relatively poor enhancement in the visualized portion of the spleen. What is the most likely cause?
A. normal arterial-phase enhancement
B. splenic infarction
C. splenic clefts
D. splenosis
E. spontaneous splenic rupture
A. normal arterial-phase enhancement
A CT pulmonary angiogram is performed during pulmonary arterial phase enhancement. During arterial phase enhancement, variable rates of flow through the splenicparenchyma result in heterogeneous enhancement, which may appear as alternatingbands of high and low attenuation, or give the impression of irregular, low-density masslesions. Enhancement becomes homogeneous in the portal venous phase.
Splenic infarction is the most common cause of (true) focal splenic defects, and typically appears as single or multiple, wedge-shaped, peripheral, low-attenuation defects.
Clefts in the splenic contour are common normal variants, appearing as smoothly contoured, medially located defects, and should not be mistaken for lacerations.
Splenosis is the implantation of splenic tissue in ectopic sites following traumatic rupture or splenectomy, and appears as multiple, small, homogeneous, enhancing masses that maymimic peritoneal deposits.
Spontaneous splenic rupture is rare, though it may be delayed following trauma or be associated with splenomegaly. Appearances may include low-density, linear, parenchymal lacerations and areas of mottled parenchymal enhancement representing contusions.
- A 64-year-old man undergoes renal ultrasound scan and is incidentally noted to have a welldefined, rounded, 3 cm lesion in the spleen. It has a thin wall with curvilinear rim calcification and contains low-level internal echoes. What is the most likely diagnosis?
A. post-traumatic (false) cyst
B. epidermoid cyst
C. echinococcal cyst
D. pyogenic abscess
E. pancreatic pseudocyst
A. post-traumatic (false) cyst
Approximately 80% of all splenic cysts are post-traumatic cysts (also known as false cysts or non-pancreatic pseudocysts), which represent the cystic end stage of trauma, infection or infarction.
They are not true cysts, as they lack an epithelial wall. They often contain internal echoes from debris and cyst wall calcification.
True cysts may be parasitic (echinococcal) or non-parasitic (epithelial). The spleen is involved in 0.9–8% of cases of echinococcal disease. Features include daughter cysts, and multiple internal dependent echogenic foci resulting in a ‘snowstorm’ sign.
Epidermoid cysts are congenital cysts with the same appearance as post-traumatic cysts, but they are rarer, and rim calcification is less commonly seen.
Pyogenic abscesses tend to appear asirregular hypoechoic areas on ultrasound scan, and hyperechoic gas bubbles may bevisible.
Intrasplenic pancreatic pseudocysts are seen in up to 5% of patients with pancreatitis.
- On contrast-enhanced CT of the abdomen, what is the most common abnormality of the spleen seen in sarcoidosis?
A. capsular calcification
B. multiple low-attenuation nodules
C. splenomegaly
D. splenic rupture
E. multiple cystic lesions
C. splenomegaly
Although symptoms directly referable to the spleen are unusual, autopsy studies have demonstrated the spleen to be involved in 38–77% of patients with sarcoidosis. The commonest abnormality demonstrated on imaging is splenomegaly, occurring in up to 60% of patients.
Multiple hypoattenuating nodules measuring up to 3 cm maybe seen distributed diffusely throughout the spleen in around 15% of cases, and may occur in the absence of splenomegaly. The lesions appear hypointense on all sequences at MRI and are best seen on T1W or early phase, gadolinium-enhanced, T2W fat suppressed sequences. Abdominal or systemic symptoms are more frequent in patients with nodular hepatosplenic sarcoidosis.
Spontaneous splenic rupture in sarcoidosis hasbeen described but is very rare.
Capsular calcification and multiple cystic lesions are notfeatures of the disease.
- A 32 year old male front seat passenger is involved in a road traffic accident and sustains blunt abdominal trauma. He is admitted via the emergency department and CT reveals a splenic laceration with subcapsular haematoma. Which one of the following associated injuries is most likely to be found?
a. Diaphragmatic rupture
b. Injury to the liver
c. Injury to the left kidney
d. Ipsilateral rib fractures
e. Injury to the small bowel mesentery
- d. Ipsilateral rib fractures
All are potential associated injuries and should be actively searched for in the context of blunt abdominal trauma.
Rib fractures are found in up to 50% of patients with splenic injuries and as such are the most common association.
The left kidney is injured in 10% of patients with splenic injury, and diaphragm rupture is even rarer.
Diaphragm rupture may be difficult to appreciate on axial slices, and may be more evident on coronal reformats.
- A 73 year old female has a CT abdomen and pelvis for the investigation of anaemia and weight loss. Massive splenomegaly (30 cm) is present with no other abnormalities. Which of the following conditions is most likely to be the underlying cause?
a. Sarcoidosis
b. Felty’s syndrome
c. Chronic myeloid leukaemia
d. Haemochromatosis
e. Non-Hodgkin’s lymphoma
- c. Chronic myeloid leukaemia
Splenomegaly is a relatively common finding in many different diseases, but massive splenomegaly always indicates underlying pathology.
Although there is no unifying definition, it is often recognised to be enlargement of the spleen into the left lower quadrant of the abdomen or crossing the midline.
All the options listed are causes of splenomegaly, however chronic myeloid leukaemia is the only listed cause of massive splenomegaly.
Other causes of massive splenomegaly include Gaucher’s disease, malaria, myelofibrosis, schistosomiasis and Leishmaniasis.
- A 32 year old woman with no significant past medical history has a CT scan as an outpatient for right iliac fossa pain. No cause for the pain is discovered on this investigation. However, a 1 cm diameter, smoothly marginated, circular, homogenous area of tissue is seen next to the splenic hilum. This area of tissue is isodense compared to normal splenic parenchyma. What is this most likely to be?
a. Splenosis
b. Splenunculus
c. Lymphoma
d. Splenic hamartoma
e. Wandering spleen
- b. Splenunculus
Splenunculus is most likely, and is often seen incidentally. It is much more common than splenosis and is more likely to occur at the splenic hilum than splenosis.
A splenunculus, or accessory spleen, is present in up to 30% of people and is most often located near the splenic hilum, but can occur anywhere in the abdomen.
Splenogonadal fusion is a recognised entity whereby the accessory splenic tissue is attached to the left ovary or testis.
Splenosis occurs following trauma, whereby splenic tissue autotransplants elsewhere in the abdomen, and can also implant above the diaphragm if associated with diaphragm rupture.
A wandering spleen denotes abnormal mobility of the spleen on long peritoneal ligaments.
@# A 47-year-old patient is referred for abdominal US. In the spleen, several rounded, thin-walled hypoechoic lesions are seen in a subcapsular position. CT shows the lesions have a density of 20 HU and there is no enhancement with intravenous contrast medium. What is the most likely diagnosis?
(a) Infarction
(b) hemangioma
(c) Lymphangioma
(d) Hamartoma
(e) abscess
(C) Lymphangioma. Corrected
These are the typical imaging features of these asymptomatic lesions. Infarcts are usually wedge-shaped, whilst the remaining lesions usually show some enhancement.
Which of the following is true of polysplenia?
(a) It has an 80% mortality in the first year
(b) It is associated with total anomalous pulmonary venous drainage
(c) It is more com common in females
(d) It is associated with right isomerism
(e) It is associated annular pancreas
(c) It is more com common in females
The remaining features are seen in asplenia, is more commonly seen in males. Polysplenia has a mortality of 50-60% and is associated with partial abnormal pulmonary venous return, isomerism and a semi-annular pancreas.
A 18 year old man undergoes an abdominal US and is found to have splenomegaly with multiple focal lesions.
Which of the following diagnoses is least likely to give these appearances?
(a) Sarcoidosis
(b) Lymphoma
(c) Portal hypertension
(d) Sickle cell disease
(e) Amyloidosis
(d) Sickle cell disease
Sickle cell disease results in chronic sequestration with a small, left occasionally calcified, spleen. The remaining diagnoses can cause splenomegaly with or without focal lesions.
A 47-year-old man undergoes a CT of the abdomen and pelvis for suspected renal colic. Other than a previous road traffic accident, the patient has no medical history. Incidentally, the radiologist finds a number of lesions throughout the abdominal cavity of uncertain aetiology. The patient subsequently undergoes a Tc-sulphur colloid study and the lesions show tracer uptake.
What is the most likely diagnosis?
(a) Peritoneal metastases
(b) Tuberculosis
(c) Sarcoidosis
(d) Splenosis
(e) Mesothelioma
(d) Splenosis
Splenosis represents the heterotopic autotransplantation of splenic tissue that usually follows traumatic rupture of the spleen.
The diagnosis may also be made with 99mTc-labelled heat denatured erythrocytes or MRI following administration of iron-oxide particles.
QUESTION 46
A 32-year-old man attends the Emergency Department 2 hours after he was assaulted outside a night club. On examination, he is hemodynamically stable with abrasions and tenderness over the lower left chest. The patient reports that he sustained significant abdominal injuries following an assault 7years ago. A contrast-enhanced CT of the chest and abdomen is performed and demonstrates a fracture of the left 10th rib, but no intrathoracic injury. There is no visible spleen but multiple small nodules of uniformly enhancing soft tissue are present in the left upper quadrant and extend to the left iliac fossa. No peritoneal free fluid is demonstrated. What is the most likely diagnosis?
A Asplenia
B Polysplenia
C Shattered spleen
D Splenosis
E Wandering spleen
D Splenosis
Previous splenic injury leads to autotransplantation of splenic tissue onto serosal surfaces within the abdomen.
- A 24-year-old male patient is brought into A&E following a high-speedRTA. His blood pressure was 90/60 mmHg and his heart rate was 112 onadmission, but these observations respond well to intravenous fluids andthe patient has remained stable since. He complains of left-sided abdominalpain. A pneumothorax is noted on CXR, with associated left-sided ribfractures. An urgent CT scan of chest and abdomen is carried out. Thisreveals fluid in the abdomen. A cresenteric area of low attenuation is notedaround the spleen. There is a further area of hypoattenuation passing 4 cminto the splenic parenchyma, adjacent to the hilum. The rest of the splenicparenchyma is of uniform attenuation. The CT also shows a flail segment of chest and an area of lung contusion at the left base. Which of the followingstatements with regard to the spleen is true?
A. The appearances described represent subcapsular haematomas.
B. The appearances described represent a haematoma and a parenchymal laceration. Thepresence of free fluid represents acute haemorrhage and a laparotomy is indicated.
C. The appearances are consistent with a shattered spleen as the laceration extends to thehilum.
D. The appearances are consistent with a subcapsular haematoma and a splenic laceration. Conservative management is appropriate with serial CT scans.
E. Whilst the appearances are consistent with a laceration and subcapsular haematoma, radiological findings are not reliable in determining the need for a laparotomy.
- E. Whilst the appearances are consistent with a laceration and subcapsular haematoma, radiological findings are not reliable in determining the need for a laparotomy.
Splenic injuries can be graded 1–5 (American Association of Trauma Surgeons). Grade 1 is a subcapsular haematoma that involves <25% of the splenic surface or a laceration <1cm deep. Grade 2 is a haematoma that involves 25–50% of the surface or a laceration up to 3cm deep. Grade 3 is a haematoma involving >50% of splenic surface or 10 cm in length or a lacerationgreater than 3 cm into the parenchyma. Grade 4 is a laceration extending into the hilum that devascularizes up to 25% of the spleen. Grade 5 is a shattered spleen, with multiple lacerationsor a spleen avulsed from its vascular bed. Radiological findings do not correlate well with requirement for laparotomy in the more minor splenic injuries. Clinical assessment is of more value, with surgery only indicated in unstable patients. The value of radiology is in detecting other injuries and in quantifying the amount of the haematoma due to the risk of delayed splenic rupture in more severe injuries.
- A 54-year-old man has a CT scan of renal tracts for suspected right renalcolic. The right renal tract is normal, but an incidental 6-cm well-defined cyst is noted within the spleen. There is no past medical history of note. What is the most likely aetiology of the splenic cyst?
A. Previous trauma.
B. Echinococcal infection.
C. Congenital cyst.
D. Liquefied infarct.
E. Unilocular lymphangioma.
- A. Previous trauma.
Splenic cysts are classified into two major subtypes: true cysts and false cysts (post-traumaticpseudocysts). This differentiation is based on the presence or absence of an epithelial lining. They cannot be distinguished on imaging. On CT as both usually appear well-defined and of fluid density. True cysts, which constitute approximately 20% of all splenic cysts and show an epithelial lining,are further divided into non-parasitic cysts and parasitic subtypes. Non-parasitic, true cysts,primarily known as epidermoid cysts, are congenitally derived from peritoneal mesotheliumand represent only 2.5% of all splenic cysts. The majority of true cysts are related to parasiticinfection, usually hydatid disease.False cysts, also known as post-traumatic pseudocysts, lack an epithelial lining and are consideredto represent the end stage of a previous intrasplenic hematoma. They account for up to 80% ofall splenic cysts. Patients may report a history of trauma to the left upper quadrant, but up to30% of patients do not recall any association with such an event. More rarely they may be theresult of previous infarction or infection. True cysts are more likely to have slight wall trabeculation and thin peripheral septation (up to86%), whereas false cysts are more likely to have mural calcification (up to 50%).Isolated splenic lymphangioma is uncommon in adults, usually being diagnosed in childhood. Itusually appears as thin-walled, well-defined masses of low attenuation, without enhancement. They may have curvilinear peripheral mural calcification.
A 65-year-old recently retired labourer had an abdominal CT to investigate general malaise. This showed multiple discrete areas of low attenuation within the spleen, which were rounded with ill-defined margins and distorted the splenic contour. It was thought that these were most likely to represent metastatic disease but the primary was not visible on the scan. What is the most likely site of the underlying primary tumour?
a Bronchogenic carcinoma
b Undetected colon carcinoma
c Renal cell carcinoma
d Prostate carcinoma
e Malignant melanoma
Answer E: Malignant melanoma
Malignant melanoma is the most common primary that metastases to the spleen. Malignant melanoma is more common in fair skinned individuals and those that spend a significant amount of time outdoors.
