Diagnostic Ultrasound - Abdomen and Pelvis

Enlarged Prostate
Differential Diagnoses: Prostate
DIFFERENTIAL DIAGNOSIS
Common
• Benign Prostatic Hyperplasia
Less Common
• Prostatic Adenocarcinoma
• Prostatitis ± Abscess
• Prostatic Cyst
• Secondary Involvement of Periprostatic Tumors: Bladder
Cancer, Colorectal Adenocarcinoma, or Gastrointestinal
Stromal Tumour
Rare but Important
• Other Primary Prostatic Tumors: Benign and Malignant
ESSENTIAL INFORMATION
Helpful Clues for Common Diagnoses
• Benign Prostatic Hyperplasia
○ By far, most common cause of prostatomegaly
○ Epithelial and stromal hyperplasia in transition zone (TZ)
and periurethral glands
○ Heterogeneously enlarged TZ compressing peripheral
and central zones
Helpful Clues for Less Common Diagnoses
• Prostate Adenocarcinoma
○ Most cases of prostate cancer do not cause global
enlargement
• Prostatitis ± Abscess
○ Prostatitis: Diffusely enlarged prostate (but may be
normal in size), global vs. focal hypoechogenicity, ↑
glandular or perilesional vascularity
– Often coexists with urinary tract infection
○ Prostatic abscess: Uni- or multilocular cyst with thick
walls/septa and peripheral hyperemia
– More common in elderly, diabetic, or
immunocompromised patients
• Prostatic Cyst
○ Large müllerian duct cysts often extend above base
• Secondary Involvement of Periprostatic Tumors
○ Urothelial carcinoma of bladder is most common tumor
to secondarily infiltrate prostate
Helpful Clues for Rare Diagnoses
• Other Primary Prostatic Tumors
○ (Giant) Multilocular Prostatic Cystadenoma
– Large multiseptated cystic pelvic mass
– Evidence of local invasion excludes this diagnosis
– Can regenerate and cause recurrent symptoms if
incomplete resection
○ Prostatic Phyllodes Tumor
– Large, well-circumscribed mass with variable amounts
of cystic and solid components
– Despite aggressive resection, up to 65% locally recur
– Up to 39% undergo sarcomatous transformation and
may spread to contiguous organs (bladder, colon)
○ Small Cell and Squamous Cell Carcinomas
– Both are very aggressive and do not change serum
prostate specific antigen; usually already advanced at
time of diagnosis
○ Prostate Sarcomas
– Most common type in children: Rhabdomyosarcoma
– Most common type in adults: Leiomyosarcoma
– Predominantly solid, heterogeneous, vascular mass;
high-grade tumors show tumor necrosis; occurs more
often in younger men (between ages of 35-60)
○ Prostate Lymphoma
– Usually secondary prostate involvement
□ Most reported is chronic lymphocytic leukemia
(CLL) or small lymphocytic lymphoma (SLL)
– Primary prostate lymphomas even more rare
SELECTED REFERENCES
1. Chu LC et al: Prostatic stromal neoplasms: differential diagnosis of cystic and
solid prostatic and periprostatic masses. AJR Am J Roentgenol.
200(6):W571-80, 2013
2. Rusch D et al: Giant multilocular cystadenoma of the prostate. AJR Am J
Roentgenol. 179(6):1477-9, 2002
3. Warrick JI et al: Diffuse large B-cell lymphoma of the prostate. Arch Pathol
Lab Med. 138(10):1286-9, 2014
(Left) Transverse
transabdominal sonogram
shows marked enlargement of
the transition zone (TZ)
causing compression of the
peripheral zone (PZ) .
Echogenic line represents the
pseudocapsule separating
the TZ from PZ. (Right)
Sagittal ultrasound from the
same patient shows elevation
of the bladder base by the
enlarged TZ.
Benign Prostatic Hyperplasia
Benign Prostatic Hyperplasia
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