Computed tomography and ultrasound examination of subcapsular prostatic cyst in a fiveyear-old dog with severe benign prostatic hyperplasia.

Computed tomography and ultrasound examination of

subcapsular prostatic cyst in a five-year-old dog with

severe benign prostatic hyperplasia

Department of Veterinary Clinical Sciences, Small Animal and Equine Reproduction1_{, Diagnostic Imaging}2_{, University of Liège, Belgium. E-mail: flore.brutinel@uliege.be}

Case

A 5-year-old entire Bullmastiff dog, initially presented for staging of an extra skeletal osteosarcoma on the right hip, had intermittent haematuria for months.

Complementary exams

- _{Abdominal computer tomographic examination (CT): Figure 1: Dorsal view of the prostate before (a) and after (b) contrast agent injection}

- _{Prostate ultrasonography (US): Figure 2: US cross section of the prostate (a) and the subcapsular prostatic cyst at colour-Doppler US (b)}

- Cytology

Treatment and outcome

- Surgical castration

- No urinary symptoms three weeks after surgery

Purpose : Description of the CT and US examination of a subcapsular prostatic cyst. To compare the imaging and the cytologic exams in a case of severe benign prostatic hyperplasia.

22st Congress of the EVSSAR June 28-29 2019 Berlin (Germany)

Diagnosis

Subcapsular prostatic cyst and severe benign prostatic hyperplasia

Conclusion

We report a cyst that collected peripherally between the parenchyma and the prostatic capsule. CT and US are sensitive to detect early prostatic changes but do not differentiate between prostatic conditions. Prostatic cytology should be performed to refine the imaging diagnosis and propose the most accurate treatment.

• Enlarged (8x7.6x5 cm), heterogeneous prostate with contrast enhancement.

• Peripheral cystic lesion on the right lobe (*). • Periprostatic fat stranding (arrow).

• Enlarged prostate (7.6x4cm in cross section), bilobed

• Anechoic, irregular-shaped area with distal enhancement between the parenchyma and the prostatic capsule of the right lobe (*)

• Hyperechoic surrounding fat suggesting secondary steatitis (arrow)

b a

a b

*

- from fluid collected by prostatic lavage, from parenchyma by ultrasound-guided fine needle aspiration (FNA) (Figure 3)

• Red blood cells (1), prostatic cells (2) • No inflammatory cells or bacteria

- From fluid collected into the subcapsular cavity

• 0.2ml of serous fluid without signs of inflammation

CT after contrast agent injection:

- Detects earlier prostatic changes than US

-> In this case : CT shows a more heterogeneous tissue structure than US. These features + steatitis : prostatitis hypothesis

- More accurate than US for evaluating prostatic size

-> Same prostatic width by CT and US (7,6cm), height underestimated by US (4 vs 5cm)

- Rarely performed when investigating the prostate (general anaesthesia, costs)

US:

- Gold standard

- US-FNA could be performed and focus on lesion detected by US

Cytology after centrifugation of fluid obtained by prostatic lavage:

- Good correlation with histology in case of inflammation - Contamination by cells of the urinary tract

US-FNA:

- Strongest correlation with histological diagnosis

- Aspiration of fibrotic tissue can lead to poor cellularity

-> No inflammation detected, both methods lead to a benign prostatic hyperplasia diagnosis

Discussion

Small intraparenchymal cysts are common findings in benign prostatic hyperplasia: Cellular hyperplasia and hypertrophy -> obstruction of ducts -> accumulation of prostatic secretions

Most cysts associated with benign prostatic hyperplasia are located within the parenchyma : we report that they can also locate between the parenchyma and the capsule.

Prostatic imaging and cytology exams to diagnose prostatic diseases

Figure 3 : Cytology of the prostatic parenchyma (FNA)

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