2 THE SECRETORY PATHWAY
2.1 Early secretory pathway
2.1.2 ER export sites and ER-to-Golgi transport
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62a
CASE 62
History
A 46-year-old female, recently emigrated to the UK from Africa, presented with symptoms of urinary frequency and urgency.
63
CASE 63
History
A 45-year-old diabetic presented with pyrexia and abdominal pain.
ANSWER 62
Observations (62a)
This single coned view of the pelvis shows curvilinear wall calcification of a relatively normal capacity bladder. No calcification of the lower ureters is seen. No discontinuity in the calcification is seen.
The history of residence in Africa raises the possibilities of bladder TB and schistosomiasis. The absence of gross bladder contraction makes the latter more likely, but it would also be helpful to review a full length abdominal film to look for upper tract calcification. Transitional cell tumour must also be excluded.
Diagnosis
Schistosomiasis.
Differential diagnosis
For calcified bladder wall:
• Cancer – primarily transitional cell carcinoma (TCC) but also other rarer bladder tumours.
• Radiotherapy.
• Infection – TB and schistosomiasis.
Discussion
Schistosomiasis is one of the most common parasitic infections, affecting 8% of the global population.
Schisto so ma hae mato b ium is the female parasite which
affects the genitourinary system. Unlike TB, which tends to affect the kidneys first and then spreads caudally, schistosomiasis has a reverse involvement and usually is confined to bladder and lower ureters. (Another case of bladder schistosomiasis [62b] is shown – note the absence of upper tract calcification that one might see in TB.)
Classically, the patient presents with urinary frequency, urgency and dysuria. Imaging findings are of:
• Calcification of the bladder – which results in reduced bladder filling capacity and increased postmicturition residual volume.
• Calcification of the lower ureters. • Lower ureteric strictures. • Ureteritis cystica.
Complications of disease affecting the genitourinary system include:
• Cystitis.
• Vesicoureteric reflux and subsequent pyelonephritis. • Increased risk of squamous cell carcinoma of the
bladder.
Other systems can be affected:
• Liver – oval migration results in portal hypertension and subsequent oesophageal varices.
• Respiratory system – diffuse granulomatous lung lesions.
Practical tips
• Schistosomiasis involves bladder and lower ureters and results in a calcified, nonshrunken bladder. TB involves the kidneys and spreads via the ureters to involve the bladder. It is very unusual to have isolated bladder involvement with TB and the degree of bladder contraction is more marked than in schistosomiasis.
• Discontinuity of calcification in the bladder wall should arouse suspicion of bladder cancer.
Further management
Follow-up in these patients is required since the latency for development of squamous cell carcinoma of the bladder can be up to 30–35 years.
62b
62b Calcification of the bladder is seen in
schistosomiasis with absence of upper tract calcification to help differentiate from TB.
Answer 63
Abdominal Imaging
Case 64
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ANSWER 63
Observations (63)
Supine abdominal radiograph demonstrates gas within the left pelvicalyceal system and upper ureter. No intra - parenchymal renal gas is seen. No gas is seen in the right renal tract or in the bladder.
Diagnosis
Emphysematous pyelitis.
Differential diagnosis
Of cause of gas in the urinary tract:
• Emphysematous pyelonephritis/pyelitis/cystitis. • Gas forming perinephric abscess.
• Trauma.
• Iatrogenic – urinary diversion procedures.
• Urinary tract fistula to bowel due to inflammation, e.g. Crohn’s, diverticulitis or spreading malignancy.
Discussion
Emphysematous pyelitis is a condition in which infective organisms produce gas, which is confined within the renal pelvicalyceal system. In emphysematous pyelonephritis, gas also forms within the renal parenchyma – a life-threatening condition that requires prompt diagnosis and treatment.
There is an increased incidence of these conditions in patients with diabetes mellitus and women are three times more commonly affected than men. Escherichia co li is the causative organism in 70% of cases with Klebsiella, Pro teus,
Candida and Pseudo mo nas organisms also being found.
In emphysematous pyelonephritis, small gas bubbles are initially seen on plain radiographs involving the renal parenchyma; this progresses to give a diffuse mottling in more advanced disease and then progresses to produce a crescent of perinephric gas when there is extension into the perirenal fat.
Practical tips
CT is the best imaging modality for assessing extent and location of gas.
Further management
Depends on cause but obviously infective causes require prompt, appropriate antibiotic treatment.
Further reading
Joseph RC, Amendola MA, Artze ME, et al. (1996). Genitourinary tract gas: imaging evaluation.
Radio Graphics 16: 295–308.
64a
CASE 64
History
A 39-year-old female presented with early satiety and epigastric pain.
ANSWER 64
Observations (64a)
Single image from a double contrast barium meal examination shows a well defined smooth walled ovoid mass lesion in the gastric antrum. A central smooth ulcer is present and no calcification is seen.
Diagnosis
Leiomyoma of the stomach.
Differential diagnosis
For target lesions: • Neurofibroma. • Lipoma (64b). • Ectopic pancreatic rest.
• Metastases – commonly breast, lung, renal and malignant melanoma.
• Haemangioma.
Discussion
This is the second most common benign gastric tumour after gastric polyps. Like oesophageal leiomyoma, these are slow growing lesions and are usually asymptomatic until
they increase in size, when there may be epigastric pain and bleeding. The gastric antrum and pylorus are the most common sites affected. The majority of these lesions extend intraluminally (60%) and form well defined ovoid defects. They are more likely to ulcerate than oesophageal leiomyoma with ulceration seen in up to 50%. Calcification is rare.
Complications include: • Bleeding.
• Obstruction.
• Intussusception – tumour can act as a lead point. • Malignant degeneration – seen in up to 15–20% of
cases.
Practical tips
Smooth, well defined, slow growing gastric lesions are likely to be benign.
Further management
Although radiological appearances suggest this to be a benign lesion, referral for endoscopy +/– biopsy should be made.
64b Axial CT image demonstrating a well defined,
smooth, rounded lesion in the stomach, which has clearly the same attenuation as intra-/extra-abominal fat. This has appearances of a gastric lipoma.