Practical uroradiology Pelvic lipomatosis q

Pelvic lipomatosis is a rare condition of a deposition of large amounts of benign adipose tissue in the pelvic cavity. It is most often seen in middle-aged black men. Clinical manifestations are nonspecific. A pear-shaped bladder is noted on intravenous urography. A diagnosis is made through imaging examinations. Computed tomography (CT) has proven to be the most useful imaging modality for differentiating the causes of a pear-shaped bladder. Surgery is indicated only to relieve ureteral obstruction.


Introduction
Pelvic lipomatosis is a rare condition of a deposition of large amounts of benign adipose tissue in the pelvic cavity. It is most often seen in middle-aged black men. Clinical manifestations are nonspecific. A pear-shaped bladder is noted on intravenous urography. A diagnosis is made through imaging examinations. Computed tomography (CT) has proven to be the most useful imaging modality for differentiating the causes of a pear-shaped bladder. Surgery is indicated only to relieve ureteral obstruction.

Case report
A 56-year-old man had one episode of flank pain 1 week previously. He visited the emergency department of our hospital, and a urine examination showed microscopic hematuria (red blood cells 3þ/high-power field). Conservative treatment was given, and the patient's flank pain resolved. Urologic outpatient follow-up treatment was advised. The patient presented to our urologic department and intravenous urography revealed lucency in the pelvic cavity, symmetrical compression and elevation of the bladder (a pear-shaped bladder), medial displacement of the bilateral distal ureters, and bilateral hydroureter and hydronephrosis ( Fig. 1). A diagnosis of pelvic lipomatosis was confirmed. CT of the abdomen revealed the same imaging findings as intravenous urography (Fig. 2). The patient was then admitted for management of the bilateral hydroureter and hydronephrosis. After admission, physical and laboratory examinations revealed normal findings. The patient was discharged after a right double-J ureteral stent was put in place. Urologic outpatient follow-up therapy was recommended.

Discussion
Pelvic lipomatosis is a condition of a deposition of large amounts of benign adipose tissue mixed with minimal fibrosis and an inflammatory reaction in the perivesical and perirenal spaces. 1 There is no known etiology. It is most often seen in middle-aged black men. It most frequently occurs in patients between 25 and 55 years of age. Clinical manifestations of pelvic lipomatosis can be urinary frequency, dysuria, perineal pain, suprapubic discomfort, backache, or mild constipation. The clinical manifestations appear unrelated in some cases.
A diagnosis relies on results from imaging examinations. A plain radiograph of the abdomen usually shows increased lucency of the pelvic cavity. Intravenous urography reveals bilateral symmetrical compression and elevation of the bladder (a pearshaped or tear-drop bladder). Medial displacement of the bilateral distal ureters may be noted because it causes bilateral hydroureter and hydronephrosis. The rectosigmoid colon may be straightened, elongated, and elevated on a barium enema examination in some cases. A pear-shaped bladder can be caused by pelvic lipomatosis, pelvic hematoma, extensively enlarged lymph nodes in the pelvic cavity, and, most commonly, a lymphoma, a large lymphocele in the pelvic cavity formed after extensive pelvic lymph node dissection, pelvic venous collaterals formed by inferior vena cava obstruction, and pelvic muscle hypertrophy. 2e7 CT was proven to be the most useful imaging modality for differentiating the causes of a pear-shaped bladder. 8e10 Although magnetic resonance imaging is well capable of differentiating the causes of pear-shaped bladder, but it has no major advantage over CT. 11,12 Surgery or double-J ureteral stent placement is indicated only to relieve ureteral obstruction.

Conflicts of interest statement
The author declares that he has no financial or non-financial conflicts of interest related to the subject matter or materials discussed in the manuscript.