Unusual histology of the prostate cancer: correlation with MRI.

Congress:

ECR 2020

Poster Number:

C-13315

Type:

Scientific Exhibit

Keywords:

Performed at one institution, Observational, Retrospective, Pathology, Cancer, Diagnostic procedure, MR, Oncology, Genital / Reproductive system male, Oncologic Imaging

Authors:

K. PÉREZ ALFONSO, D. Pittí Freiburghaus, E. Merino Merino, E. Condom Mundo, X. Bonet Punti, J. Garcia Bennet; Barcelona/ES

DOI:

10.26044/ecr2020/C-13315

DOI-Link:

https://dx.doi.org/10.26044/ecr2020/C-13315

Fig. 2: Prostatic rhabdomyosarcoma in a 71 years old patient. Axial T1-WI showing a low...

Fig. 3: Mucinous adenocarcinoma in a 57 year old patient with an intermediate grade...

Fig. 4: Granulomatous prostatitis in a 66 year old patient. Nodular/ovoid lesion in the...

Fig. 1: Ductal adenocarcinoma in a 63 years old patient with suspicious signs of...

Table 1: Tumor variants and atypical findings in 308 prostatectomies performed at our...

Table 2: Clinical presentation of the tumor variants and atypical findings of 308...

Table 3: MRI findings of the tumor variants and atypical findings of 308 prostatectomies...

Results

Atypical histological findings were found in 18 patients (5,8%): 14 tumor variants (4,5%) and 4 non-cancerous normal tissue (1,3%). These were 10 ductal adenocarcinomas (DA) (3,2%), 2 neuroendocrine (NE) tumors (0,6%), 1 rhabdomyosarcoma (RS) (0,3%) and 1 mucinous adenocarcinoma (MA) (0,3%). Granulomatous prostatitis (GP) was present in 3 (1%) patients. One (0,3%) patient presented amyloid deposits. Patients had a mean age of 59, with the lowest mean (53) associated with NE differentiation (Table 1).

Obstructive symptoms were reported only in one patient with DA and in the patient with RS. Only the RS showed no significant PSA increase. One of the patients with GP had a medical history of high-grade papillary vesical cancer treated with intravesical BCG. None of the patients had disseminated disease at diagnosis (Table 2).

All patients underwent pre-surgical biopsies except for one that had a transurethral resection of the prostate. Only two patients (20%) with DA were diagnosed with this variant at pre-surgical biopsy.

In addition to the atypical findings, presence of acinar adenocarcinoma was described in all samples, except in amyloid prostatitis. Worth noting the high ISUP 2014 grade found in both NE tumors.

A staging MRI was performed in 8 of the 10 patients with DA. All DA were located in the peripheral zone (PZ), except for one. All showed low T2-WI signal, restricted diffusion, and avid enhancement (Fig. 1).

Both patients with NE differentiation showed a lesion that was isointense in T1-WI, hypointense in T2-WI and restricted diffusion. DCE was only available in one patient, showing mild enhancement.

The RS showed MRI findings different from those of typical adenocarcinomas, with low T1-WI signal, no restricted diffusion or enhancement. It is worth mentioning it was the only tumor with high T2-WI signal (Fig. 2).

The MA had an isointense T1-WI, mild-low T2-WI signal, and mild enhancement. Contrary to acinar and DA, it showed no diffusion restriction (Fig. 3). Abnormalities reported in all 3 patients with GP were located in the PZ, showing a homogeneous pattern of intermediate-high T1-WI signal, mild hypointense T2-WI signal, restricted diffusion, and early contrast enhancement (Fig. 4). Amyloid prostatitis showed no relevant MRI findings (Table 3).

80% of DA and the amyloid tumor presented biochemical recurrence (mean time of 8 and 5 months respectively).