Pelvic lipomatosis is a rare disease by excessive proliferation of the mature fat in the pelvic extraperitoneal space. Cystitis cystica, often occur-ring concurrently with pelvic lipomatosis, is a rare proliferative inflammatory disease of the bladder. The diagnosis of pelvic lipomatosis is established on radiographic examination, not on pathology. We report a case of pelvic lipomatosis associated with cystitis cystica and chronic metaplasia of the urinary bladder.
Key words: Cystitis cystica; Lipomatosis
Pelvic lipomatosis is a rare disease of unknown etiology presenting with excessive proliferation of the mature fat in the pelvic cavity. The proliferating adipose tissue may compress the pelvic viscera, includ-ing the pelvic portion of the ureters, rectosigmoid colon and vessels, in varying degrees. Therefore the presenting symptoms usually vary and suggest nonspe-cific diseases referable to the pelvis or urinary tract. There may be no symptoms in pelvic lipomatosis and is usually discovered incidentally. But occasionally, marked bilateral ureteral obstruction may lead to the development of uremia.
Pelvic lipomatosis has been associated with various yet often unrelated disorders including: cystitis cystica, cystitis glandularis, adenocarcinoma of the bladder, chronic urinary tract infection, hypertension, recurrent superficial thrombophlebitis [1], constipa-tion, vesicoureteral reflux, retroperitoneal fibrosis, nontropical chyluria [2], and the Proteus syndrome [3]. Therefore early diagnosis and early treatment of asso-ciated disorders before late sequelae develop are important. Here, we reported a case of pelvic lipomato-sis associated with cystitis cystica proved by cysto-scopic biopsy.
CASE REPORT
A 25-year-old young man was admitted due to progressive frequency and left inguinal pain in recent 2 days. He had suffered from recurrent frequency, dysuria, nocturia, painless hematuria, lower abdominal soreness and bilateral flank soreness since 3 years ago.
Physical examination revealed 180.6 cm in body height and 68 kg in body weight. There was no evi-dence of bleeding tendency, abdominal tenderness, costophrenic angle knocking pain, fever, hypertension, hypotension, hemihypertrophy, macrodactyly, various subcutaneous masses or scoliosis. But left spermatic cord tenderness was noted. Urine routine showed pro-teinuria, hematuria and pyuria.
Reprint requests to: Dr. Jeon-Hor Chen
Department of Radiology, China Medical College Hospital. No. 2, Yuh-Der Road, Taichung 404, Taiwan, R.O.C.
Pelvic Lipomatosis Associated with Cystitis
Cystica and Chronic Metaplasia of the
Urinary Bladder: a case report
WEI-CHINGLIN1 YUAN-HONGTZENG1 JEON-HORCHEN1 CHI-LONGCHEN2The plain film of the abdomen showed radiolu-cent area in the pelvis. The intravenous urography (IVU) demonstrated severe bilateral hydronephrosis and hydroureters with tapering of bilateral lower ureters and marked elevation of the bladder base (Fig. 1a). The bladder had a strikingly abnormal configura-tion, simulated an inverted pear (Fig. 1b). There was also straightening and elevation of the rectosigmoid colon on a barium enema study (Fig. 2). CT revealed abundant fatty tissue with increased vascularity in the pelvic space, bladder deformity and mild rectal com-pression. Small cystic lesions in the thickened bladder wall secondary to inflammation, edema and prolifera-tive changes were also detected on CT image (Fig. 3). The magnetic resonance image (MRI) simulated CT findings. Thickening of the urinary bladder wall, dilated bilateral lower ureters and compressed rectum were, however, more prominent than CT due to better tissue-contrast in MR image (Fig. 4).
Cystoscopy revealed polyps in trigone of the urinary bladder and prostatic urethra. Transurethral multiple biopsies of the urinary bladder in body, neck, and posterior trigone portions were performed. The pathological report was cystitis cystica (Fig. 5a) with intestinal epithelium metaplasia noted in the mucosa and submucosa of the urinary bladder (Fig. 5b).
After the diagnosis was confirmed, bilateral per-cutaneous nephrostomies were performed; bilateral double J stents were also inserted antegradely. After the symptoms were released, the pigtail catheters of
bilateral percutaneous nephrostomies were removed. The patient was then discharged and regularly fol-lowed up at our out-patient department.
DISCUSSION
Pelvic lipomatosis is nonmalignant overgrowth of adipose tissue with minimal fibrotic and inflammatory components compressing structures within the pelvis. It occurs most frequently in a specific group of patients: middle age (25-60 years old); usually
over-Figure 1. Intravenous
urography (IVU): a. At-60-minute spot film shows severe bilateral hydronephrosis and hydroureters with tapering of bilateral lower ureters and marked elevation of the bladder base. b. U-bladder filling-view discloses diffuse radiolucent area in the pelvic cavity. The bladder simulates an inverted pear.
1a 1b
Figure 2. Barium enema study demonstrates
“hot air balloon” appearance of the bladder on IVU [5] and a rigid and ascended rectosigmoid colon on barium enema. The final diagnosis of pelvic lipomato-sis is confirmed by CT and MRI findings. The ultra-sonography might show hyperechoic masses and bladder deformity. But due to marked echogenecity associated with fat and bowel gas, a specific diagnosis usually cannot be made. Cystourethrography reveals
Figure 5. Histological
exami-nation of the urinary bladder mucosa reveals chronic infla-mmation with morphology of von Brunn’s nests (—), cystitis cystica (➤), cystitis glandularis (), and chronic intestinal
metaplasia (). (a. X40, HE
stain), (b. X200, HE stain)
5a 5b
Figure 3. Contrast-enhanced CT scan of the pelvis
reveals abundant fatty tissue with increased vascularity. The bladder wall is markedly thickening due to inflammation and edema. Cystic lesions are noted in thickened bladder wall (). Dilated bilateral lower ureters and mild rectal compression are also seen.
Figure 4. Fast spin echo T2-weighted MR image
(27443/95 msec/0.50) (TR / TE / excitations) on axial section of the pelvis demonstrates similar findings as
Figure 3: thickening of the urinary bladder wall, dilated
bilateral lower ureters and compressed rectum are, however, more prominent than CT due to better tissue-contrast in MR image.
weight but not obesity, and man predominant (10:1) [4]. Clinical symptoms are nonspecific and include urinary frequency, urinary tract infection, dysuria, hematuria, fever, constipation, and abdominal or low back pain. Therefore pelvic lipomatosis is often found incidentally on radiography.
The diagnosis is suggested by radiological triad of hyperlucency of the pelvis on plain abdomen film,
an elevated pear-shaped bladder and an elongated and anteriorly displaced prostatic urethra [6]. Although multiplanar MRI is able to detail fatty masses and pro-vides delineation of cephalad displacement of the bladder base, elongation of the bladder neck and pos-terior urethra, and elevation of the prostate gland, it offers little benefit over CT except for showing char-acteristic medial and superior displacement of the seminal vesicles and fatty tissue separating the prostate gland from the rectum [7]. Pelvic angiography is helpful to distinguish inflammatory disease from neoplastic disease. Inflammatory vessels are smaller (less than 0.3 mm in diameter) and the venous phase appears later than in malignancy. An increased vascu-lar supply is always noted in pelvic lipomatosis, but the characteristic larger vessels, rapid venous filling, tumor stain, displacement, and amputation associated with malignancy are not found. It is emphasized that the differentiation of pelvic lipomatosis from malig-nant neoplasm without laparotomy depends on demon-stration of the typical radiolucency surrounding the bladder and rectum. But if malignancy is highly sus-pected, exploratory laparotomy may be necessary [8].
An increased incidence of proliferative cystitis such as cystitis cystica or cystitis glandularis in associ-ated with pelvic lipomatosis has been noted. The cause of these associated proliferative changes, however, remains unknown [8]. Cystitis cystica is a nonspecific inflammatory process of the urinary bladder wall. It is commonly seen with von Brunn’s nests and cystitis glandularis in the inflamed bladder or around the stalk of papillary tumors and the margins of sessile or inva-sive tumors. Von Brunn’s nests, cystitis cystica, and cystitis glandularis are three related condition. Von Brunn’s nests are formed by buds or sprouts of transi-tional epithelium that grow down from the surface into the underlying lamina propria and later become sur-rounded by condensed layer of connective tissue that eventually separated them from the overlying cells. Central cavitation of the nests or infolding of the surface epithelium, with the formation of crypts that become obstructed, will lead to the formation of cysti-tis cystica. In the fully formed cysts there is a lining of flattened or low cuboid cells, and if the cysts are of sufficient size, the mucosal surface becomes irregular and has a granular appearance. Cystitis glandularis is produced when the cells lining the cysts differentiate into columnar epithelium. Typical goblet cells are sometimes present, and the epithelium resembles intestinal mucosa named intestinal metaplasia. It is widely regarded as premalignant and may evolve into adenocarcinoma of the urinary bladder. There is increased risk of adenocarcinoma if more extensive
intestinal metaplasia develops in the bladder wall [9]. These chronic proliferative changes of the bladder are demonstrated as multiple small round filling defects on IVU [10], mucosal elevations on ultrasound and cystic lesions may be seen within the thickened bladder wall on CT [11] and MRI image. Sometimes a single defect may mimic transitional cell carcinoma [12] and the final diagnosis is based on his-tology.
The prognosis of pelvic lipomatosis depends on various factors including onset of the disease, if there is association with other disorders, and development of sequelae. There is a higher risk of progressive ureteral obstruction in young, stocky or obese men with vague pelvic symptoms. While pelvic lipomatosis in men older than 60 years old usually discovered during evaluation of other problems, often prostatism, might have no serious sequelae and no significant pro-gression of disease [8]. Some patients with pelvic lipo-matosis might develop uremic encephalopathy if they are loss of follow-up. Therefore regular follow-up and an early intervention before irreversible changes occur are important.
In conclusion, pelvic lipomatosis is usually asso-ciated with cystitis cystica and chronic metaplasia. Early diagnosis and early treatment of these associated disorders before late sequelae develop can be achieved through careful radiological evaluation.
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