Canine prostatic serum esterase and strain and 2D-shear wave sonoelastography for evaluation of normal prostate in dogs: Preliminary results.

Canine prostatic serum esterase (CPSE) is considered a useful tool to identify prostate disorders in dogs, with increasing interest in ultrasound (US)-based sonoelastography to non-invasively detect prostate disorders. Since no report is available about a possible correlation between these diagnostic tools, we aimed to investigate a possible correlation between strain elastography (SE) and 2D-shear wave elastography (SWE) and CPSE. Twenty-one dogs were included and, on each animal, CPSE was evaluated followed by a complete US examination and SE and 2D-SWE application. Healthy dogs were identified based on the CPSE results. All the dogs included were characterized by normal CPSE values (<52.3 ng/mL) and normal US prostate appearance. The prostate was characterized by intermediate stiffness with SE (pattern III - 84.7% for the left lobe and 79.27% for the right lobe) and softer than the abdominal wall (SR 0.6 for the left lobe and 0.56 for the right lobe), with low values for both m/s and kilopascals (kPa) for 2D-SWE, pointing that the healthy tissue is not hard. 2D-SWE results were, respectively, 13.51 ± 5.55 kPa and 2.31 ± 0.42 m/s for the left lobe and 18.05 ± 6.47 kPa and 2.39 ± 0.43 m/s for the right lobe. The significant difference between the right and left measurements expressed with kPa, not evidenced with m/s, can be considered indicative of m/s as the most reliable measurement to be considered regarding the prostate parenchyma. Even though no linear correlation was detected between CPSE and elastography values, these preliminary results evidence that the healthy prostates were characterized by a similar elastographic pattern, thus pointing that these techniques can be potentially useful to be applied in case of prostatic disorders to improve the accuracy of the final diagnosis in a non-invasive way.

Surgical treatment and outcome of sterile prostatic cysts in dogs.

OBJECTIVE: To describe the surgical treatment and outcome of a large cohort of dogs with sterile prostatic cysts (PCs). STUDY DESIGN: Retrospective study. ANIMALS: Forty-four client-owned dogs. METHODS: Dogs with sterile PCs with at least 6 months of follow-up were included. Clinical variables, type of surgery, complications, recurrences, and outcomes (telephonic interviews or rechecks) were recorded. RESULTS: Extra- and intraparenchymal cysts were diagnosed in 29 and 11 dogs, respectively. Four dogs had both types. Extraparenchymal cysts were treated by partial resection and omentalization (n = 22) and complete resection (n = 7). Drainage and intracapsular omentalization were performed in all dogs with intraparenchymal cysts. The four dogs with both types of cyst were treated by omentalization. Resolution was documented in 39/44 dogs (88.6%). Intraoperative complications occurred in one dog (urethral tear). Major complications resulting in death occurred in three dogs (oliguric kidney injury, cardiac arrhythmia, and persisting urinary tract obstruction). Minor complications (n = 10) consisted of temporary urinary incontinence (n = 2), permanent urinary incontinence (n = 5), urinary retention (n = 2), and dysuria (n = 1). Recurrence occurred in two dogs with extraparenchymal cysts. Median long-term follow-up was 528 days (range, 250-730 days). Thirty-nine dogs had no signs associated with prostatic disease at long-term follow-up. CONCLUSION: Partial or complete resection and/or omentalization of sterile PCs led to resolution of clinical signs in most dogs, although postoperative urinary incontinence was frequent. IMPACT: This study is the largest case series relative to canine sterile PCs treated surgically and provides evidence on the prognosis and rate of complications.

An unusual case of infected uterus masculinus in a dog.

BACKGROUND: Paraprostatic cysts are large structures that develop between the prostate gland and urinary bladder, usually in older, intact dogs. Their incidence is reported to be 1.1-5.3% in dogs with prostatic disease. The aetiology of paraprostatic cysts is not fully understood, but they are believed to develop from the uterus masculinus. Whereas the uterus masculinus has been reported to communicate with the urethra in men and horses, no communication between the uterus masculinus and urethra has been identified in dogs. CASE PRESENTATION: An entire male dog was presented with a bloody discharge from its penis and tenesmus of 5 days' duration. A diagnosis of cystic uterus masculinus was made on the basis of the findings of abdominal ultrasonography and histopathology of tissues obtained during an exploratory laparotomy. In addition, a Sertoli cell tumour affecting both testes was diagnosed following scrotal castration. The cystic uterus masculinus was completely resected, after which the tenesmus and bloody discharge resolved. Thus, cystic uterus masculinus should be considered as a differential diagnosis for a paraprostatic cyst when such a lesion develops as part of the feminising effect of a Sertoli cell tumour. CONCLUSIONS: Cystic uterus masculinus should be considered as a differential diagnosis for tenesmus and penile discharge, and for structures resembling paraprostatic cysts. This case report confirms that a uterus masculinus can communicate with the urethra in dogs, as in other species, and demonstrates endocrine responsiveness, manifesting as epithelial and glandular metaplasia and mucus production, with the potential for subsequent infection.

Clinical approach to prostatic diseases in the dog.

In small animal practice, prostatic diseases are increasingly encountered. All dogs may experience prostatic disease, but particular care should be addressed to breeding dogs, in which prostatic affection may lead to decrease in semen quality and fertility. The most common prostatic disease is the benign prostatic hyperplasia (BPH) followed by prostatitis, prostatic neoplasia and prostate squamous metaplasia. These diseases do not have pathognomonic symptoms, therefore, making a correct diagnosis may not be easy. An accurate clinical examination and a correct diagnostic protocol are essential in order to begin the most appropriate treatment, and also to do a good prophylaxis where it is possible. BPH therapy is usually recommended when mild-severe signs are present or if symptoms disturb the patient. New therapeutic approaches, both medical and surgical, allow to maintain fertility in most animals with prostatic disorders. Prostate cancer is relatively infrequent. Elective therapy is the surgical one, but it is considered palliative and can result in important post-operative complications. The aim of this paper is to lay down the most appropriate diagnostic process describing the aetiologies of prostatic disease, their symptoms, the right investigative tools and therapy.

Prostatic Lesions in Odontocete Cetaceans.

The prostate is the only accessory male genital gland described in cetaceans. Although few studies describe the gross and histologic anatomy of the prostate in cetaceans, there is no information on pathological findings involving this organ. The prostate glands of 45 cetaceans, including 8 different odontocete species ( n = 44) and 1 mysticete, were evaluated. The main pathologic diagnoses were verminous prostatitis, septic prostatitis, viral prostatitis, benign prostatic hyperplasia, and prostatitis of unknown etiology. Verminous prostatitis ( n = 12) was caused by nematodes of the genus Crassicauda, and different presentations were observed. Septic prostatitis, identified in 2 cases, both involved nematode infestation and Clostridium spp coinfection. One case of viral prostatitis was identified and was associated with morbillivirus infection. In prostatitis of unknown cause ( n = 7), varying degrees of prostatic lesions, mostly chronic inflammation, were identified. Impacts at individual levels (eg, localized disease, loss of reproductive capacity) and population levels (eg, decreased reproductive success) are plausible. Our results indicate a high occurrence of prostatic lesions in free-ranging odontocetes. For this reason, the prostate should be routinely inspected and sampled during necropsy of odontocete cetaceans.

Accuracy of ultrasonography and fine-needle aspiration cytology in the diagnosis of prostate diseases in dogs.

Clinical signs of prostatic diseases in dogs are often non-specific. Appropriate treatment should be based on a detailed investigation using reliable diagnostic tools. The aim of our study was to evaluate the diagnostic value of ultrasonography (US) and fine-needle aspiration (FNA) cytology in dogs' prostate diseases. The mean accuracy of FNA cytology and US were 0.72 and 0.88 (n = 13), respectively. US gland size measurements and actual gland dimensions were highly concordant. Obtained results confirm the high diagnostic value of US and FNA biopsy and in prostatic diseases. Diagnosis based on US is highly reliable; however, it should be combined with clinical signs. Therefore, cytological evaluation of prostate gland material may be performed to differentiate or confirm presumptive diagnosis.

Computed tomography: a beneficial diagnostic tool for the evaluation of the canine prostate?

BACKGROUND: Prostatic diseases in intact male dogs are common. However, studies about the computed tomographic (CT) examination of the prostate in dogs are rare. The aim of the present study was to evaluate age related-changes in the canine prostate with the help of the CT and to evaluate whether measuring Hounsfield Units (HUs) in different morphological conditions of the prostate is of diagnostic value. Fifty pre- and post-contrast CT scans of the prostate of dogs were evaluated and divided into three groups according to the tissue structure: Group1 dogs with homogenous prostate tissue (16/50); group 2 with prostate cysts (26/50) and group 3 with inhomogeneous prostate tissue (8/50). The prostatic dimensions were measured and the ratio between length, height and width and the sixth lumbar vertebra was calculated. Median values of prostatic attenuation measured in HUs, using regions of interests (ROIs) were determined on pre- and post- contrast scans over the whole length of the prostate. The results were compared to the dog's age. Furthermore, the CT Images were compared with the results of ultrasonography (47/50). RESULTS: On pre-contrast scans HUs within ROIs placed in the prostate did not differ statistically significantly between the different morphological groups (1: 37.7; 2: 36.3; 3: 39.8 HU). HUs within on the post- contrast scans showed statistically significant differences between the groups. Group one had a mean density of 93.6 HU, group two had a mean density of 106.1 HU and group three had one of 138.2 HU. The prostatic size in the first group was smaller than in the other groups, whereas the largest prostates were found in the second group. In six cases the post-contrast CT scan showed results that differed from the ultrasound examination. Dogs had a homogenous tissue in ultrasonography while the CT scan revealed an inhomogeneous tissue structure. CONCLUSIONS: The CT examination can be a beneficial diagnostic tool for examining the prostatic size and for evaluating the prostatic tissue. The different HUs reflected age-related changes and alterations in the prostate while measuring the density of the prostate. Contrast agent application enables a more specific analysis of the prostate to be carried out and for precise changes in tissue structure to be observed.

Evaluation of dogs with macroscopic haematuria: a retrospective study of 162 cases (2003-2010).

AIMS: To retrospectively describe clinical features of dogs that were presented to a small animal clinic between 2003-10 with macroscopic haematuria, and investigate whether signalment of the dog and severity and duration of the haematuria at admission were associated with specific aetiologies. METHODS: Medical records were evaluated of 162 dogs with macroscopic haematuria admitted to a University-based small animal clinic in Thessaloniki, Greece, from January 2003 to December 2010. The inclusion criteria were discolouration of the urine sediment combined with abnormal numbers of erythrocytes, when examined microscopically. Data collected from the medical records included signalment, severity, frequency and duration of haematuria, and diagnosis. RESULTS: Between January 2007 and December 2010, 8,893 dogs were admitted to the clinic; of these 99 (1.1%) were admitted with haematuria. Of the 162 dogs with records of haematuria, 80 (49.4%) were aged between 5.1-10 years, presented with acute (96/162; 59.3%), constant (99/162; 61.1%) and mild/moderate (150/162; 92.6%) haematuria. Of 147 dogs with a recorded diagnosis, the commonest diagnoses were urinary tract infection (UTI, 42/147; 28.6%), urolithiasis (38/147; 25.9%), prostatic disease (25/147; 17.0%) and urinary tumours (13/147; 8.8%). The prevalence of UTI was higher in female (22/56; 39%) than male (20/91; 22%) dogs, and in medium sized (22/52; 42%) than small (6/40; 15%) dogs. Urolithiasis was most prevalent in small (21/40; 52.5%) dogs, and all dogs with urolithiasis presented with mild/moderate haematuria. The prevalence of prostatic disease was highest in large (11/46; 24%) and giant (3/9; 33%) sized dogs and in dogs aged >10 years (8/30; 27%). CONCLUSIONS AND CLINICAL RELEVANCE: In this retrospective study from one small animal clinic, UTI, urolithiasis, prostatic disease and urinary tumours predominated among the causes of canine haematuria. The consideration of sex, age, and size of the dog and characteristics of haematuria were found to be useful parameters when forming the list of differential diagnoses.

Inguinal herniation of a mineralized paraprostatic cyst in a dog.

A firm mass was noted in the right inguinal subcutaneous region of an 11-year-old intact male Labrador retriever dog presented for right pelvic limb weakness. Pelvic radiographs showed 2 large ovoid structures with circumferential thin eggshell-like mineralization in the right external inguinal region. The structures were confirmed sonographically, and on magnetic resonance imaging as a large folded herniated mineralized paraprostatic cyst through a defect in the right inguinal wall. To the author's knowledge, this is the first published report of an inguinal herniated mineralized paraprostatic cyst.

Herniation inguinale d'un kyste paraprostatique minéralisé chez un chien. Une masse ferme a été observée dans la région sous-cutanée chez un Labrador retriever mâle intact âgé de 11 ans qui était présenté pour une faiblesse du membre pelvien droit et des radiographies pelviennes ont montré deux grosses structures ovoïdes avec une mince minéralisation circonférencielle semblable à une coquille d'oeuf dans la région inguinale droite. Les structures ont été confirmées par échographie et à l'imagerie par résonance magnétique comme un gros kyste paraprostatique replié minéralisé et hernié via un défaut de la paroi inguinale droite. À la connaissance de l'auteur, il s'agit du premier rapport publié d'un kyste paraprostatique minéralisé hernié inguinal.(Traduit par Isabelle Vallières).

Ultrasonographic features of uterus masculinus in six dogs.

Uterus masculinus (persistent Mullerian duct) is a vestigial embryological remnant of the paramesonephric duct system in males and has been associated with clinical signs such as dysuria, incontinence, tenesmus and urethral obstruction in dogs. The radiological appearance of cystic uterus masculinus in dogs has been described previously with the aid of retrograde positive or negative contrast cystography. The purpose of this retrospective study was to describe ultrasonographic features of confirmed or presumed uterus masculinus in a group of dogs with confirmed or presumed disease. Ultrasonographic findings were recorded based on a consensus opinion of two readers. A uterus masculinus was defined as cylindrical when no lumen was observed and tubular when it had lumen that was filled with anechoic fluid. Six dogs met the inclusion criterion with a mean age of 8 years and 9 months. Uterus masculinus appeared as single (four dogs) or two (two dogs) horn-like, tubular (four dogs) or cylindrical (two dogs) structures, originating from the craniodorsal aspect of the prostate gland and extending cranially. The walls of the uterus masculinus were isoechoic to the urinary bladder wall. The diameter of the observed uterus masculinus varied from 0.3 cm to 1 cm. The length of the uterus masculinus varied from 2 cm to 6.5 cm but the cranial terminal end was not identified in two dogs. Concomitant prostatomegaly was seen in five dogs (83.3%) and urinary tract infection was noted in three dogs (50%). Findings indicated that uterus masculinus should be included as a differential diagnosis for male dogs with these ultrasonographic characteristics.

Diagnosis of common prostatic conditions in dogs: an update.

Prostatic diseases account for 3-10% of intact male dogs presented to veterinary surgeons. Conditions vary according to severity and frequency ranging from the most common, such as prostatic hyperplasia and cysts to the rarer conditions such as prostatic abcesses and neoplasia. Different causes of prostatic disease can often not be distinguished by evaluation of clinical signs, as these are not very distinctive and may be similar for many prostatic conditions. Understanding which additional diagnostic tools to use for each of the possible conditions is essential in making a correct diagnosis leading to the proper treatment. This article will discuss the different etiologies, age groups of dogs and the decision-making process which will help the practitioner to choose the right investigative tools, treatments and prognosis when dealing with prostatic disease.

Multidrug-resistant Escherichia coli causing canine pyometra and urinary tract infections are genetically related but distinct from those causing prostatic abscesses.

Despite extensive characterisation of uropathogenic Escherichia coli (UPEC) causing urinary tract infections (UTIs), the genetic background of non-urinary extraintestinal pathogenic E. coli (ExPEC) in companion animals remains inadequately understood. In this study, we characterised virulence traits of 104 E. coli isolated from canine pyometra (n = 61) and prostatic abscesses (PAs) (n = 38), and bloodstream infections (BSIs) in dogs (n = 2), and cats (n = 3). A stronger association with UPEC of pyometra strains in comparison to PA strains was revealed. Notably, 44 isolates exhibited resistance to third-generation cephalosporins and/or fluoroquinolones, 15 were extended-spectrum ß-lactamase-producers. Twelve multidrug-resistant (MDR) strains, isolated from pyometra (n = 4), PAs (n = 5), and BSIs (n = 3), along with 7 previously characterised UPEC strains from dogs and cats, were sequenced. Genomic characteristics revealed that MDR E. coli associated with UTIs, pyometra, and BSIs belonged to international high-risk E. coli clones, including sequence type (ST) 38, ST131, ST617, ST648, and ST1193. However, PA strains belonged to distinct lineages, including ST12, ST44, ST457, ST744, and ST13037. The coreSNPs, cgMLST, and pan-genome illustrated intra-clonal variations within the same ST from different sources. The high-risk ST131 and ST1193 (phylogroup B2) contained high numbers of ExPEC virulence genes on pathogenicity islands, predominating in pyometra and UTI. Hybrid MDR/virulence IncF multi-replicon plasmids, containing aerobactin genes, were commonly found in non-B2 phylogroups from all sources. These findings offer genomic insights into non-urinary ExPEC, highlighting its potential for invasive infections in pets beyond UTIs, particularly with regards to high-risk global clones.

Unusual presentation of alveolar echinococcosis as prostatic and paraprostatic cysts in a dog.

BACKGROUND: Alveolar echinococcosis (AE) is caused by the larval stage (metacestode) of Echinococcus multilocularis. The domestic dog can act as a definitive host and harbor adult cestodes in its small intestine or become an aberrant intermediate host carrying larval stages that may cause severe lesions in the liver, lungs and other organs with clinical signs similar to AE in humans. CASE PRESENTATION: A case of canine AE, affecting the liver and prostate with development of multilocular hydatid paraprostatic cysts and possible lung involvement is described in an 8-year-old neutered male Labrador retriever dog.The dog presented with progressive weight loss, acute constipation, stranguria and a suspected soft tissue mass in the sublumbar region. Further evaluation included computed tomography of the thorax and abdomen, which revealed cystic changes in the prostate, a paraprostatic cyst, as well as lesions in the liver and lungs. Cytological examination of fine-needle aspirates of the liver, prostate and paraprostatic cyst revealed parasitic hyaline membranes typical of an Echinococcus infection and the presence of E. multilocularis-DNA was confirmed by PCR. The dog was treated with albendazole and debulking surgery was considered in case there was a good response to antiparasitic treatment. Constipation and stranguria resolved completely. Six months after the definitive diagnosis, the dog was euthanized due to treatment-resistant ascites and acute anorexia and lethargy. CONCLUSIONS: To the authors' knowledge, this is the first publication of an E. multilocularis infection in a dog causing prostatic and paraprostatic cysts. Although rare, E. multilocularis infection should be considered as an extended differential diagnosis in dogs presenting with prostatic and paraprostatic disease, especially in areas where E. multilocularis is endemic.

B-mode and contrast-enhanced ultrasonographic findings in canine prostatic disorders.

Ultrasound is a common imaging technique used for examination of the dog's prostate gland that has proven to be successful for diagnosis of many clinical conditions. Whilst B-mode ultrasound is useful for assessment of the prostate gland, there appears to be substantial variation in the appearance of some pathological conditions, although individual experienced ultrasonographers often have a high aptitude for making a correct diagnosis. Here, we report the normal volume and appearance of the canine prostate gland with B-mode ultrasound and use thematic analysis to identify the categories described by experienced ultrasonographers when reporting both normal and abnormal findings. Four thematic categories were identified: background echotexture, parenchymal stippling, generalized appearance and focal changes. We found that a relatively narrow variety of thematic variables (descriptors) were used for reporting of prostatic pathology within these thematic categories. There was also poor association between these descriptors and the underlying pathology, with the only unique descriptors being 'cysts' for benign prostatic hyperplasia and 'parenchymal mineralization' for adenocarcinoma. In comparison with the limitations of B-mode ultrasound, we document the value of measurement of vascular perfusion kinetics using contrast-enhanced ultrasound and demonstrate how perfusion kinetics differ between benign and malignant prostatic disease.

Assessment of vascular perfusion kinetics using contrast-enhanced ultrasound for the diagnosis of prostatic disease in dogs.

Vascular perfusion was assessed in 10 dogs without prostatic abnormalities and 26 dogs with prostatic disease using contrast-enhanced ultrasound. The time to reach peak contrast intensity (TTP) and peak perfusion intensity (PPI) were measured, and histological biopsies were collected from each dog. Biopsies confirmed normal prostate (n = 10), benign prostatic hyperplasia (n = 11), mixed benign pathology (n = 9), prostatitis (n = 1), prostatic malignancy [adenocarcinoma (n = 4); leiomyosarcoma (n = 1)]. In normal dogs, mean PPI was 16.8% ± 5.8 SD, and mean TTP was 33.6 ± 6.4 s. Benign conditions overall were not statistically different from normal dogs (p > 0.05); for benign prostatic hyperplasia, mean PPI was 16.9 ± 3.8%, and mean TTP was 26.2 ± 5.8 s; for mixed benign pathology mean PPI was 14.8 ± 7.8%, and mean TTP was 31.9 ± 9.7 s; for prostatitis, PPI was 14.2%, and TTP was 25.9 s. The malignant conditions overall had perfusion values that differed from the normal dogs (p < 0.05), although evaluation of the data for individual malignancies did not demonstrate a consistent trend; for adenocarcinomas, the PPI was numerically higher with a mean of 23.7 ± 1.9%, and the mean TTP was 26.9 ± 4.8 s, whilst for the dog with leiomyosarcoma values were numerically lower with a PPI of 14.1% and TTP of 41.3 s. Contrast-enhanced ultrasound appears to offer some ability to document differences in perfusion that may differentiate between malignant and benign lesions, although studies with larger numbers of animals are required to confirm this contention.

Blastomyces dermatitidis prostatic and testicular infection in eight dogs (1992-2005).

This was a retrospective case study of eight dogs diagnosed with prostatic or testicular B. dermatitidis infection. Signalment, clinical presentation, diagnostic procedures, and treatment options were evaluated. Review of medical records of dogs diagnosed with blastomycosis at the University of Illinois Veterinary Teaching Hospital from 1992 to 2005 yielded four dogs with prostatic blastomycosis (PB) and four dogs with testicular blastomycosis (TB). Three of the four dogs with PB and all four dogs with TB had evidence of urogenital disease. Three dogs with PB had an elevated body temperature and all had systemic disease. All dogs with TB had a normal body temperature, and three had systemic disease and one had clinical signs limited to testicular disease. Cytology or histopathology was used to diagnose PB or TB. Treatment included itraconazole or fluconazole with or without nonsteroidal anti-inflammatory drugs. PB and TB are infrequently recognized and may be under diagnosed due to failure to specifically evaluate these tissues. PB or TB should be considered in the evaluation and staging of male dogs with blastomycosis. Male dogs with urogenital signs should be evaluated via prostatic or testicular cytology or histopathology since proper identification and management of PB or TB may improve overall treatment success.

Two cases of paraprostatic cysts in castrated male dogs.

Two castrated male dogs presented for evaluation of tenesmus. Presurgical evaluations included complete physical examinations, serum biochemistry, abdominal ultrasonography, and MRI (case 2 only). Paraprostatic cysts were diagnosed in both cases based on the results of abdominal ultrasonography, MRI, and histopathology of tissue samples obtained during exploratory laparotomy. To the authors' knowledge, the two cases presented herein are the first documented cases of paraprostatic cysts that developed after castration in male dogs. Paraprostatic cysts should be considered in the differential diagnoses for castrated male dogs with prostatic disease.

Cyclosporine treatment of perianal gland adenoma concurrent with benign prostatic hyperplasia in a dog.

A 13-year-old, intact male, mixed-breed dog was evaluated for multiple intradermal nodules around the anus. The nodules were diagnosed as perianal gland adenoma based on histopathologic examination. After therapy with cyclosporin A for 5 wk, the perianal masses were moderately shrunken. The dog's condition has remained stable over 6 mo.

Laparoscopy-guided prostate biopsy in dogs--a study of 13 cases.

This paper describes laparoscopy-guided prostate biopsy experiments in 13 dogs. Biopsy material was evaluated histopathologically to diagnose causes of prostatic gland enlargement. Laparoscopic biopsy was performed in male dogs diagnosed with prostatic gland enlargement, based on clinical symptoms and results of rectal examinations.

[Development of a large intraprostatic cyst following the use of a GnRH agonist-implant in a male dog with benign prostatic hyperplasia]. / Entwicklung einer großen intraprostatischen Zyste nach Einsatz eines GnRH-Agonist-Implantats bei einem Rüden mit benigner Prostatahyperplasie.

A male dog with benign prostatic hyperplasia and several small intraprostatic cysts was treated with a GnRH-agonist implant containing 4,7 mg deslorelin (Suprelorin®). Within 2 weeks after the implantation, the prior urethral bleeding worsened. A large intraprostatic cyst was detected sonographically. The patient was subsequently treated with osaterone acetate (0.4 mg/kg p. o. once a day for 7 days) and enrofloxacin (5 mg/kg p. o. once a day for 21 days). The clinical symptoms receded within 10 days. Within one month, the cyst regressed completely. The mechanisms of cyst enlargement are discussed.