Prostatic Carcinoma

Fig. 24.1

Hypoechoic area localized in the peripheral portion of the left prostatic lobe

Fig. 24.2

Neoplasm localized in the anterior horn in the left prostatic lobe (Red arrows)

Fig. 24.3

Hypoechoic focus of nodular hyperplasia. This area is not suspicious for PC, because of its localization in the TZ (Red arrows)

Fig. 24.4

Large PC, involving also the TZ, which is hyperechoic, with asymmetrical left prostatic lobe (Red arrows)

24.3 Echogenicity

24.3.1 Hypoechoic Lesions

Hypo-echogenicity is the most frequent presentation of neoplastic lesions (Fig. 24.5). About 60 % of involved areas with PC are hypoechoic, but only 17–57 % of hypoechoic areas are PC at final histology. The difference of the echogenicity of the different tissues is not always so clear (Fig. 24.6), and diagnosis of a PC requires an optimization of the gray scale and of the set of US machine. The color Doppler might be helpful in the identification of structural anomalies in some cases.

Fig. 24.5

Large hypoechoic focus in the left prostatic lobe

Fig. 24.6

Mildly hypoechoic nodule located in the peripheral zone, in the right paramedian part. This nodule corresponds to an area with increased consistence during palpation (Red circle)

The intraprostatic hypoechoic images, particularly those located in the peripheral zone, are considered suspicious for neoplasia [6], and several studies revealed the correlation between this finding and PC [7, 8]. Recent publications [9] highlight the presence of hypoechoic areas as significantly related to the diagnosis of high-grade PC (Gleason score >7) and that they might be considered predictive of a clinically significant disease.

24.3.2 Isoechoic Lesions

Thirty to forty percent of PC shows an isoechoic appearance. The isoechoic lesions may be very different: small lesions, usually with low histological grade, only identified by random PB (T1c stage), classical lesions, whose echogenicity is similar to the adjacent prostatic parenchyma that is not highlighted only with US. In these cases, color Doppler might be helpful in pinpointing lesions and in suggesting bioptic sampling (Fig. 24.7). Eventually, sometimes, even voluminous and infiltrating lesions might be difficult to be diagnosed in US, if no attention is paid in evaluating the anomalies of the margins or of the lack of differentiation between the peripheral and the transitional zone.

Fig. 24.7

Prostatic neoplasm with isoechoic structure, evidenced with ecocolordoppler help, with contrast medium (white arrows)

24.3.3 Hyperechoic Lesions

The hyperechoic lesions are the most rare (5–10 %), and the observation of microcalcifications inside the neoplasia (“black and white”) occurs in about 2 % of diagnoses (Fig. 24.8). These US features are generally associated with cancer with poorly differentiated histology (Gleason score 9–10) (Fig. 24.9).

Fig. 24.8

Apical right lesion with microcalcifications inside (Red circle)

Fig. 24.9

Prostatic neoplasm approximately extended to all the prostate, with “black and white” appearance. The pathological exam showed a poorly differentiated neoplasm (5 + 4 Gleason score)

The pseudo-cystic lesions are very rare. They show a significant cystic component, an extra prostatic evolvement, and a compressed and often hypervascularized tissue margin (Fig. 24.10).

Fig. 24.10

Unusual pseudo-cystic neoplasm with extraprostatic extension and a hypervascularized solid component

24.4 Role of TRUS in Prostatic Cancer Diagnosis

About 30 % of US detectable PCs shows a nodular and engaged appearance, whereas in more than 50 %, the images show irregular margins with infiltrating appearance. It has been demonstrated that the presence of US-suspected lesions is closely related to the cancer-detection rate and, above all, to high-grade neoplasms [10, 11].

Nevertheless, the TRUS has many limits in PC diagnosis, and these limits reduce the sensitivity and the specificity of this method [12, 13].

There are many factors that could be considered:

About one third of neoplasms might be isoechoic or with an echogenicity similar to “normal” peripheral zone (in particular well-differentiated lesions with a glandular morphology very similar to the normal structure).
Hypoechoic area may be observed during acute flogosis (Fig. 24.11), with the presence of post-ischemia necrotic areas, of small nodular hyperplastic areas either of vascular structures or of fibro-muscular tissue.

Fig. 24.11

Hypervascularized and hypoechoic lesions in granulomatous prostatitis (post-BCG) might simulate neoplastic lesions
Up to 20 % of the PCs may originate from transitional zone, and their differentiation from the normal tissue with altered echogenicity is very difficult.

The TRUS accuracy in staging PC is low [13] with a sensitivity that has been reported to be 50–85 % and a specificity 46–90 % in detecting an extracapsular extension (cT3) (Figs. 24.12, 24.13, and 24.14). These parameters are even lower when considering the seminal vesicle invasion (accuracy <70 %).

Fig. 24.12

Hypoechoic lesions with poorly defined margins, in recent acute prostatitis (white arrows)

Fig. 24.13

Hypoechoic lesion located in the left lobe; in the sagittal plane, the irregularity of capsule is evident

Fig. 24.14

Hypoechoic area in the left lobe. In this case the extracapsular extension is not so evident (Red circle)

The future of US is to offer, in conjunction with MRI, a guide for prostate biopsy, in order to reduce the side effects of multiple random biopsies, to focus the diagnosis only to clinically significant neoplasm, and to reduce the diagnosis of incidental microfoci which are clinically irrelevant.

Only gold members can continue reading. Log In or Register to continue