Fetal cardiac calcifications: report of four prenatally diagnosed cases and review of the literature

Fetal cardiac calcifications are defined as diffuse hyperechogenicities in the different layers of the heart. This is an uncommon fetal ultrasound finding associated with significant myocardial dysfunction. We report four cases with massive fetal myocardial calcifications detected on prenatal ultrasound at 18-22 weeks' gestation and associated, in all cases, with significant cardiac dysfunction. Detailed fetal echocardiographic evaluation, chromosome analysis, and an extensive search for intrauterine infection as a cause of these abnormalities, were carried out on all cases. A thorough autopsy was performed on all deceased fetuses and postnatal investigation of the sole survivor was performed. Two of our patients chose to interrupt their pregnancies, one fetus suffered intrauterine demise, and one child was born alive. In all of our cases the karyotypes were normal, and no specific infectious etiology or maternal autoantibody was noted. Histopathology findings in the non-survivors included myo- and epicardial calcification maximal at the base of the heart. The living child has findings suggestive of an intrauterine infection, although no infectious entity was identified. Long-term follow-up showed sensorineural hearing loss and severe developmental delay.

Prenatal diagnosis of horseshoe kidney by measurement of the renal pelvic angle

OBJECTIVE

The aim of this study was to evaluate the usefulness of measurement of the angle between bilateral renal pelves on axial views in the prenatal ultrasonographic diagnosis of horseshoe kidney.

METHODS

We retrospectively measured the renal pelvic angle in 19 fetuses with horseshoe and 20 fetuses with normal kidneys in the second and third trimesters. Renal pelvic angle was defined as the angle between the long axis of the renal pelves on the axial view of the abdomen. We compared the renal pelvic angles of horseshoe and normal kidneys with unpaired t-test. Taking 140 degrees as a cut-off value, we calculated the sensitivity, specificity and accuracy of pelvic angle measurement for the prenatal diagnosis of horseshoe kidney.

RESULTS

The mean pelvic angles in the fetuses with horseshoe kidney were 116 degrees and 110 degrees in the second and third trimester, respectively. In the normal fetuses, the equivalent angles were 172 degrees and 161 degrees. The difference between the two groups was statistically significant (P < 0.01). Using 140 degrees as the discriminating criterion, the sensitivity, specificity and accuracy of renal pelvic angle measurement for the prenatal diagnosis of horseshoe kidney were all 100%. Fifteen of 19 fetuses with horseshoe kidney had no other abnormality. Four (21%) fetuses had severe complex abnormalities which were associated with trisomy 18 in three cases.

CONCLUSION

Observation and measurement of the renal pelvic angle is a simple and useful method in the prenatal diagnosis of the horseshoe kidney.

Measurement of nuchal skin fold thickness in the second trimester: influence of imaging angle and fetal presentation

OBJECTIVE

To assess the effect of imaging angle and fetal presentation on the measurement of nuchal skin fold thickness (NFT) in the second trimester.

METHODS

Fetal NFT was prospectively measured in 921 women at 18-21 weeks' gestation. The population was divided into two groups according to fetal presentation. Group A comprised 643 fetuses in cephalic or transverse presentation and Group B comprised 278 fetuses in breech presentation. To determine whether there was a difference in NFT depending on imaging angle, in Group A the NFT was measured on the standard axial horizontal images and then on images obtained after moving the transducer about 30 degrees toward the occiput. In Group B an assessment was made as to whether NFT changed with fetal presentation. Initial measurements were made with the fetuses in breech presentation. Repeat NFT measurements were made after 15 min in 64 fetuses that had converted to cephalic or transverse presentation. Statistical analysis was performed using a paired t-test.

RESULTS

The mean NFT on the standard horizontal image was 5.2 mm, while that on the 30 degrees occiput image was 4.0 mm. The difference was significant (P < 0.001). One hundred and twenty-three (19.1%) fetuses had a NFT greater than 6 mm on the standard image, but only two (0.3%) had an NFT of > 6 mm on the 30 degrees occiput image. There were no chromosomal or structural abnormalities in the 123 fetuses in which the NFT was > 6 mm. The mean NFT of 64 fetuses in the breech presentation was 4.4 mm, while it was 3.9 mm when they had converted to other presentations. The difference was statistically significant (P = 0.001). In breech presentation, 13/64 (20.3%) fetuses had a NFT greater than 6 mm compared to only one (1.6%) fetus in the other presentations. There were no structural or chromosomal abnormalities in any fetus with a NFT > 6 mm in either group.

CONCLUSIONS

In this study the NFT measurement varied with scan direction and fetal presentation. To avoid falsely thickened NFT measurements the scan should be directed to image the posterior surface of the occipital bone. This can be achieved by scanning from a 30 degrees occipital direction. Also, NFT is greater in fetuses in a breech presentation. Attention to these details can reduce false-positive NFT measurements.

Prenatal ultrasound findings of lissencephaly associated with Miller-Dieker syndrome and comparison with pre- and postnatal magnetic resonance imaging

OBJECTIVE

To report on the prenatal ultrasound findings in fetuses with lissencephaly associated with Miller-Dieker syndrome (MDS) and to compare these findings with those of magnetic resonance imaging (MRI).

METHODS

Cases of MDS confirmed by postnatal chromosome microdeletion analysis were identified through review of patient records. Prenatal ultrasound scans were reviewed retrospectively by two radiologists. For cerebral cortical development, the Sylvian, parieto-occipital and calcarine fissures, and the cingulate sulcus and sulci over the cerebral convexity were evaluated. If one or more of these fissures or sulci were not visualized at the expected gestational age or their appearance was abnormal for gestational age, cortical development was considered delayed. Prenatal and postnatal MRI examinations were reviewed by a pediatric neuroradiologist.

RESULTS

There were seven cases of MDS. In three cases, the prenatal diagnosis of agyria/lissencephaly was prospectively suspected by ultrasound at 23, 26 and 30 weeks, and subsequently confirmed by prenatal MRI. When we retrospectively reviewed the prenatal ultrasound scans of all fetuses, all had delayed cortical development identified on ultrasound performed after 23 weeks' gestation. In all cases the Sylvian fissure was abnormal on both ultrasound and MRI. In one fetus, a normal cortical appearance for gestational age was seen at the initial 20-week ultrasound examination, but delayed cortical development was identified at a 24-week scan. Mild ventriculomegaly was seen in six fetuses and dysgenesis of the corpus callosum in one. Extracranial abnormalities were detected in five fetuses. Delayed cortical development was seen in two fetuses with mild ventriculomegaly, but no other fetal anomalies.

CONCLUSIONS

In fetuses with MDS, delayed cortical development can be suspected on ultrasound as early as 23 weeks' gestation. This finding warrants further investigations including MRI and FISH analysis for chromosome 17p13.3 deletion.

How early are fetal cerebral sulci visible at prenatal ultrasound and what is the normal pattern of early fetal sulcal development?

OBJECTIVES

To evaluate the time of appearance and pattern of development of fetal cerebral sulci at prenatal ultrasound.

METHODS

We studied 50 normal fetuses for visibility of cerebral sulci, especially sulci which appear early in anatomical studies, namely the parieto-occipital fissure, calcarine sulcus, cingulate sulcus, convexity sulci and insula/Sylvian fissure. The gestational ages of the fetuses studied ranged from 15.6 to 29.6 weeks.

RESULTS

Sulci could be seen by transabdominal ultrasound as early as 18.5 weeks. Medial hemispheric sulci and the insula were visible earlier and more confidently than convexity sulci. The earliest gestational ages at which specific sulci could be seen in any fetus were as follows: parieto-occipital fissure 18.5 weeks, calcarine sulcus 18.5 weeks, cingulate sulcus 23.2 weeks and convexity sulci 23.2 weeks. In the present series, the gestational ages at which these sulci were always visible were as follows: parieto-occipital fissure >20.5 weeks, calcarine sulcus >21.9 weeks, cingulate sulcus >24.3 weeks and convexity sulci >27.9 weeks. The insula and its margin (the circular sulcus) and the overgrowing opercula undergo characteristic maturation. The circular sulcus at the margin of the insula was initially smooth but started becoming angular after about 17 weeks as it started to be overgrown by the parietal and temporal lobe opercula. Initially the insula/operculum angle was obtuse. An acute angle was first evident at 23.2 weeks and in all fetuses older than 24.5 weeks. Our ultrasound data were consistent with anatomical studies and fetal magnetic resonance imaging findings.

CONCLUSIONS

Some cerebral sulci can be seen at prenatal ultrasound as early as 18.5 weeks. Familiarity with the normal pattern of sulcal development and the discriminating gestational ages for the appearance of different sulci may allow early suspicion of lissencephaly.

Caroli's disease: prenatal diagnosis, postnatal outcome and genetic analysis

Caroli's disease is a rare autosomal recessive condition characterized by cystic dilatation of the intrahepatic bile ducts and infantile polycystic kidney disease. We report a case with Caroli's disease detected prenatally at 33 weeks' gestation with fetal ultrasound findings of a cystic liver mass and echogenic kidneys. Postnatal investigation confirmed enlarged and echogenic kidneys with dilatation of the intrahepatic bile ducts consistent with the diagnosis of Caroli's disease. Genetic analysis of the gene, PKHD1, associated with autosomal recessive polycystic kidney disease (ARPKD) showed that the patient had compound heterozygous mutations, confirming that this early onset Caroli's disease was part of the spectrum of ARPKD. To our knowledge this is the third case of Caroli's disease detected prenatally and the first in which the infant survived.

Identification of numerical chromosomal changes detected by interphase fluorescence in situ hybridization in high-grade prostate intraepithelial neoplasia as a predictor of carcinoma

CONTEXT

High-grade prostate intraepithelial neoplasia (HPIN) is the most likely precursor of prostate cancer. The condition of many patients with a diagnosis of HPIN in prostate needle core biopsy could, if left untreated, progress to invasive cancer. Currently there is no available clinical, immunohistochemical, or morphologic criteria that are predictive of this progression.

OBJECTIVE

To determine whether chromosomal instability in these precursor lesions could increase their predictive value for cancer detection.

DESIGN

Dual-color interphase fluorescence in situ hybridization analysis was performed on archived prostate needle core biopsies from 54 patients with initial diagnosis of isolated HPIN and follow-up of 3 years or more. We used commercially available centromere probes for chromosomes 4, 7, 8, and 10. We had interpretable results in 44 patients as follows: (1) group A: 24 HPIN patients with persistent HPIN and/or benign lesions in the follow-up biopsies, and (2) group B: 20 HPIN patients with progression to prostate carcinoma.

RESULTS

Twenty-five percent of the patients in group B displayed numeric chromosomal aberrations. Only 8.3% of the patients from group A had chromosomal abnormalities (P =.1). The observed overall chromosomal changes in HPIN were higher than those in normal or hyperplastic epithelium, with a statistically significant difference (P <.05). All aberrations were detected in the form of chromosomal gain. Overall, the commonest aberration was gain of chromosome 8, followed by gains of chromosomes 7 and 10.

CONCLUSION

These results indicated that although no single numeric chromosomal abnormality could be assigned as a predictor of HPIN progression to carcinoma, the overall level of numeric chromosomal abnormalities shows a trend of elevation in HPIN patients whose condition subsequently progressed to carcinoma.

Positioning errors and prostate motion during conformal prostate radiotherapy using on-line isocentre set-up verification and implanted prostate markers

PURPOSE

To evaluate treatment errors from set-up and inter-fraction prostatic motion with port films and implanted prostate fiducial markers during conformal radiotherapy for localized prostate cancer.

METHODS

Errors from isocentre positioning and inter-fraction prostate motion were investigated in 13 men treated with escalated dose conformal radiotherapy for localized prostate cancer. To limit the effect of inter-fraction prostate motion, patients were planned and treated with an empty rectum and a comfortably full bladder, and were instructed regarding dietary management, fluid intake and laxative use. Field placement was determined and corrected with daily on-line portal imaging. A lateral portal film was taken three times weekly over the course of therapy. From these films, random and systematic placement errors were measured by matching corresponding bony landmarks to the simulator film. Superior-inferior and anterior-posterior prostate motion was measured from the displacement of three gold pins implanted into the prostate before planning. A planning target volume (PTV) was derived to account for the measured prostate motion and field placement errors.

RESULTS

From 272 port films the random and systematic isocentre positioning error was 2.2 mm (range 0.2-7.3 mm) and 1.4 mm (range 0.2-3.3 mm), respectively. Prostate motion was largest at the base compared to the apex. Base: anterior, standard deviation (SD) 2.9 mm; superior, SD 2.1 mm. Apex: anterior, SD 2.1 mm; superior, SD 2.1 mm. The margin of PTV required to give a 99% probability of the gland remaining within the 95% isodose line during the course of therapy is superior 5.8 mm, and inferior 5.6 mm. In the anterior and posterior direction, this margin is 7.2 mm at the base, 6.5 mm at the mid-gland and 6.0 mm at the apex.

CONCLUSIONS

Systematic set-up errors were small using real-time isocentre placement corrections. Patient instruction to help control variation in bladder and rectal distension during therapy may explain the observed small SD for prostate motion in this group of patients. Inter-fraction prostate motion remained the largest source of treatment error, and observed motion was greatest at the gland base. In the absence of real-time pre-treatment imaging of prostate position, sequential portal films of implanted prostatic markers should improve quality assurance by confirming organ position within the treatment field over the course of therapy.

Interstitial microwave thermal therapy for prostate cancer: method of treatment and results of a phase I/II trial

PURPOSE

Interstitial microwave thermal therapy is experimental treatment for prostate cancer with the goal of curing disease, while causing fewer complications than standard treatment options. We present a method for delivering interstitial microwave thermal therapy using microwave radiating helical antennae inserted percutaneously under transrectal ultrasound guidance. We report the results of a trial of this method in 25 patients in whom primary external beam radiation therapy had previously failed. This patient group currently has limited curative options that are associated with a high complication rate. However, these recurrent tumors often remain localized to the prostate, and so they may be amenable to localized therapy.

MATERIALS AND METHODS

Patients with proved prostatic adenocarcinoma were candidates for treatment when prostate specific antigen (PSA) was 15 ng./ml. or less and prostate volume was 50 cc. or less. Followup included PSA measurement, digital rectal examination, urinalysis, and documentation of adverse events at 4, 8, 12 and 24 weeks. Sextant biopsy was performed at week 24. The procedure involved the insertion of 5 antennae percutaneously through a modified brachytherapy template. The antenna arrangement was determined based on computer simulated predictions of temperature throughout the prostate. The prostate was dissected away from the rectum by an injection of sterile saline to provide a thermal barrier that protected the rectum from thermal damage. Temperatures were monitored using interstitial mapping thermistor probes that were also inserted through the template. A minimum peripheral target temperature of 55C but less than 70C was maintained for 15 to 20 minutes, while the urethra, rectum and hydrodissection space remained below 42C. The urethra and rectum were actively cooled in addition to hydrodissection.

RESULTS

Peripheral target temperatures of 55C were achieved. The urethra and rectum remained at a safe temperature. The procedure, including setup and treatment, required approximately 2.5 hours of operating room time. At 24 weeks the PSA nadir was 0.5 ng./ml. or less in 52% of patients and 0.51 to 4 ng./ml. was achieved in an additional 40%. The negative biopsy rate at 24 weeks was 64%, assuming that 3 patients lost to followup would have had positive results. No major complications were observed and in most cases minor complications resolved within 3 months.

CONCLUSIONS

Interstitial microwave thermal therapy for prostate cancer was developed to heat the prostate safely to a cytotoxic temperature. Experience with 25 patients in whom external beam radiation therapy for prostate cancer had failed indicates that the treatment is safe. Although our series indicates that this therapy may be effective, further studies and longer followup are required in larger patient groups to confirm the potential role of this therapy as an option for recurrent and primary prostate cancer.

V89L polymorphism of type-2, 5-alpha reductase enzyme gene predicts prostate cancer presence and progression

OBJECTIVES

The valine (V) to leucine (L) polymorphism of the SRD5A2 gene is associated with 5-alpha reductase-2 activity; patients with the V allele have high activity and patients with the L allele have low activity. We examined whether this polymorphism predicts the presence of prostate cancer in 320 men without cancer who underwent biopsy and cancer progression in 318 men who underwent radical prostatectomy.

METHODS

The effect of the SRD5A2 gene in predicting the presence of prostate cancer was examined using logistic regression analysis, controlling for established risk factors. The effect of the SRD5A2 gene in predicting prostate cancer progression was examined using a nested, matched, case-control design. Most of the participants were white.

RESULTS

Of the 320 men, 158 (49.4%) were found on biopsy to have prostate cancer. The overall distribution of the V/V, V/L, and L/L genotypes was 47.5%, 42.5%, and 10.0%, respectively. The adjusted odds ratio for having prostate cancer for patients with at least one V allele was 2.53 compared with patients with the L/L genotype (P = 0.03). Of the 318 patients with cancer, 80 had biochemically detected recurrence and 238 had no evidence of recurrence. The odds ratio for progression for patients with at least one V allele was 3.32 (95% confidence interval 1.67 to 6.62, P = 0.0006) compared with patients with the L/L genotype.

CONCLUSIONS

Men who have the V allele of the SRD5A2 gene have a twofold increase in the risk of prostate cancer development and an additional twofold increase in the risk of progression compared with men with the L/L genotype.

Inverted duplication of the distal short arm of chromosome 3 associated with lobar holoprosencephaly and lumbosacral meningomyelocele

A fetus with lobar holoprosencephaly and lumbosacral meningomyelocele associated with duplication of the short arm of chromosome 3 is reported. The anomalies were detected on fetal ultrasound at 20 weeks' gestation and the autopsy findings correlated well with the prenatal findings. The fetal karyotype was 46,XY,der(3)del(3)(p26) dup(3)(p26p21.3). The association of holoprosencephaly with duplication 3p is well known, but to the best of our knowledge this is the first reported association of meningomyelocele with 3p duplication. These findings suggest that a gene or genes with a crucial role in central nervous system development are located on the short arm of chromosome 3.

Serum human glandular kallikrein-2 protease levels predict the presence of prostate cancer among men with elevated prostate-specific antigen

PURPOSE

We hypothesize that serum human glandular kallikrein-2 (hK2) levels predict the presence of prostate cancer among men prescreened by prostate-specific antigen (PSA).

PATIENTS AND METHODS

We conducted a cross-sectional study of 324 men who had no history of prostate cancer and who were referred for prostate biopsy. PSA and hK2 levels were measured using specific nonisotopic immunometric techniques. Cases were patients who were diagnosed with adenocarcinoma of the prostate from biopsy, and controls were patients who had no evidence of cancer from biopsy. The odds ratio for detection of prostate cancer was determined for hK2 measurements, controlling for age, total-PSA level, digital rectal examination, and symptoms of urinary obstruction.

RESULTS

Of 324 men, 159 (49.1%) had cancer. Mean hK2 levels and hK2:free-PSA ratios were significantly higher in cases than in controls (1.18 v 0.53 ng/mL, respectively, for hK2, P =.0001; 1.17 v 0.62 for hK2:free-PSA ratio, P =.0001). The crude odds ratio for prostate cancer detection for patients in the highest quartile of hK2 level was 5.83 (95% confidence interval [CI], 2.8 to 12.1; P =.0001) compared with patients in the lowest quartile. The adjusted odds ratio was 6.72 (95% CI, 2.9 to 15.6; P =.0001). Similarly, the crude and adjusted odds ratios for prostate cancer detection using the hK2:free-PSA ratio were 7.36 (95% CI, 3.6 to 15.1; P =.0001) and 8.06 (95% CI, 3. 7 to 17.4; P =.0001), respectively. These odds ratios were higher than that observed for prostate cancer detection by total-PSA level (2.73; P =.03).

CONCLUSION

Among men prescreened with PSA for prostate cancer, patients with high hK2 measurements have a five- to eight-fold increase in risk for prostate cancer, adjusting for PSA level and other established risk factors. hK2 measurements may be a useful adjunct to PSA in improving patient selection for prostate biopsy.

A comparative analysis of sextant and an extended 11-core multisite directed biopsy strategy

PURPOSE

The 3 tumor locations unsampled by conventional sextant biopsies that have been identified on composite 3-dimensional reconstruction of 180 radical prostatectomy specimens are the anterior transition zone, midline peripheral zone and inferior portions of the anterior horn in the peripheral zone. We evaluated an 11-core multisite directed biopsy scheme incorporating these alternate areas and conventional sextant biopsies in 362 patients from 2 institutions.

MATERIALS AND METHODS

Patients without a prior diagnosis of cancer underwent ultrasound guided 11-core biopsies which included conventional sextant and 3 alternate sites. All specimens were separated for specific location identification. Biopsy was performed in 183 patients at MD Anderson Cancer Center (group 1) and in 179 at Toronto General Hospital (group 2). All group 2 and 54% of group 1 patients (98 of 183) had a prior biopsy negative for cancer.

RESULTS

Median prostate specific antigen was higher in group 2 than in group 1 patients (11.5 versus 9.5 ng./ml., p = 0.016). Overall a 33% increase (36 of 110 patients) in cancer detection was observed when biopsy technique included the alternate areas (p = 0.0021). The anterior horn was the most frequently positive biopsy site followed by the transition zone and midline sites. The 11-core technique had significantly better cancer detection rates when digital rectal examination and transrectal ultrasound were normal, and in men with serum prostate specific antigen between 4.1 and 10 ng./ml.

CONCLUSIONS

Biopsies of the alternate sites suggested by our simulation studies are feasible and reproducible. This new strategy significantly enhanced (p = 0.0075) prostate cancer detection compared to conventional sextant biopsies in men undergoing a repeat procedure.

Prostate cancer: MR imaging and thermometry during microwave thermal ablation-initial experience

Percutaneous interstitial microwave thermoablation of locally recurrent prostate carcinoma was continually guided with magnetic resonance (MR) imaging. Phase images and data were obtained with a rapid gradient-echo technique and were used to derive tissue temperature change on the basis of proton-resonance shift. Thermally devitalized regions correlated well with the phase image findings. MR imaging-derived temperatures were linearly related to the fluoroptic tissue temperatures. MR imaging can be used to guide thermoablation.

Prenatal detection of cerebral lesions in a fetus with tuberous sclerosis

We report a newborn, diagnosed prenatally with both cardiac rhabdomyomas and a brain tumor. To the best of our knowledge, this is the first report of central nervous system (CNS) lesions detected prenatally in a child with tuberous sclerosis with term follow-up. At 36 months, the child has normal growth and is developing appropriately. Thus the finding of CNS tumors on fetal ultrasound examination can help in the prenatal diagnosis of tuberous sclerosis but does not necessarily indicate a poor prognosis.

Association of free PSA percent, total PSA, age, and gland volume in the detection of prostate cancer

BACKGROUND

Measurement of the free fraction of total prostate-specific antigen (fPSA%) has been proposed as a useful addition to total PSA for the detection of prostate cancer.

METHODS

We assessed the performance of fPSA% in differentiating men with prostate cancer from men without cancer in a group of 1,709 subjects studied in five institutions.

RESULTS

On the basis of PSA testing, digital rectal examination, and ultrasound examination conducted at one or more visits, 229 cancers were diagnosed. The mean fPSA% in men with cancer was 9.1% compared to 18.9% in men without cancer. The fPSA% varied by age, with men under 60 having a mean fPSA of 13.9% compared to 17.5% in men 60-69 years old and 19.8% in men over age 70. Significant associations of fPSA% with gland volume and PSA level were also observed. The sensitivity, specificity, and positive predictive value of different fPSA% cutoff levels were assessed in 513 men who underwent sextant biopsy. Sensitivity of 85.4%, 32.1% specificity, and a 39.2% positive predictive value were observed using an fPSA cutoff of 15% in men with PSA in the 4.0-9.9 ng/ml range. Sensitivity of 96.9%, 12.3% specificity, and a 36.2% positive predictive value were observed using an fPSA cutoff of 20% in the same men. If 15% fPSA had been used as a biopsy criterion in men with PSA of 4.0-9.9 ng/ml, the number of biopsies performed could have been reduced by 21.2%, with a concomitant reduction in cancer detection of 14.6%. Using a 20% fPSA criterion, biopsies would have been reduced 12.7%, with a 3.1% reduction in cancer detection.

CONCLUSIONS

These results provide some evidence that the detection of prostate cancer is enhanced by measuring fPSA% in addition to the established measure of total PSA level. Further research is needed to identify other markers that have better sensitivity and specificity.

Congenital toxoplasmosis: prenatal diagnosis, treatment and postnatal outcome

We report a female patient with congenital toxoplasmosis who presented with hydrops fetalis and cerebral abnormalities, detected on fetal ultrasound. Following prenatal treatment, the hydrops fetalis resolved and at four months of age she has normal growth and development. This case emphasizes the potential good prognosis in cases with congenital toxoplasmosis detected and treated prenatally.

Interstitial microwave thermoablation for localized prostate cancer

The conventional treatment for localized prostate cancer can be associated with significant morbidity and cost. Interstitial microwave thermoablation is a minimally invasive procedure used experimentally to treat selected patients with failed radiation therapy of prostate cancer at our institution. Preliminary results in these patients suggest that this treatment might be a useful alternative in selected patients with previously untreated localized prostate cancer. In this report we describe the first use of percutaneous transperineal interstitial microwave thermoablation to treat a case of primary prostate cancer. There were no treatment complications. At 18 months the patient's serum prostate-specific antigen remains undetectable, and his prostate biopsy shows no evidence of malignancy. These very preliminary but exciting results in this single patient suggest that this experimental technique should be explored further.