physiological sites of fdg uptake are well documented , with urinary bladder being one of these . since it is the route of tracer excretion , any pathology related to urinary bladder grade iii cystocele was incidentally seen on fdg pet / ct done for a 65 year old lady , which was identified due to a large area of tracer concentration in communication with the urinary bladder . she had severe cough with expectoration since 2 months , which aggravated over last one month . posteroanterior chest radiograph showed consolidation involving the lower lobe of left lung , following which she was treated with broad spectrum antibiotics . since there was no improvement in her symptoms and her radiographic findings , lung malignancy was suspected . she was referred for a whole body 18 fluoride fluorodeoxyglucose positron emission tomography / computed tomography ( 18 f fdg pet / ct ) , for further evaluation of a possible malignant etiology . maximum intensity projection ( mip ) images revealed low grade fdg uptake in left lung [ figure 1-arrowhead ] , corresponding to the consolidation and ground glass opacification seen on the ct component of the study . physiological tracer distribution was seen in the heart , brain , liver and urinary bladder . however , a distinct focus of intense fdg uptake was seen inferiorly , separate from the urinary bladder [ figure 1-arrows ] . the intense nature of the fdg concentration was similar to that of urinary tracer accumulation in the bladder . axial ct images showed that the uptake corresponded to a well defined rounded lesion , which was protruding out from the introitus and had a fluid density figure 2-arrow ] . sagittal fused pet / ct images revealed that there was definite communication with the bladder , suggesting the possibility of herniated bladder [ figure 3-arrows ] . subsequent clinical evaluation confirmed that the intensely tracer concentrating structure at the introitus was a grade 3 cystocele . mip image showing fdg uptake in left hemithorax corresponding to lung mass ( arrowhead ) and two large foci of uptake in the pelvis ( arrows ) axial ct image showing cystocele protruding from the introitus ( arrow ) sagittal fused images shows tracer concentration in bladder and cystocele suggestive of definite communication ( arrows ) fdg is excreted by kidneys without reabsorption by proximal tubules , as a result of which increased tracer uptake is seen in the renal collecting system , ureters , and bladder . there are occasions when urinary tracer concentration can simulate pathology resulting in false positive pet studies . commonly , tracer activity in the ureter can be focal and mimic a retroperitoneal node . also , in patients with previous transurethral resection of prostate , urine may be retained in the dilated prostatic urethra , which passes through the midline of prostate . intense tracer activity in the bladder is always a hindrance as it compromises the sensitivity of fdg pet for neighboring adnexal organs . the intense nature of tracer concentration in the urinary bladder normally is very suggestive and is easily recognized as physiological uptake . however , on certain occasions such as post surgery or radiation therapy the normal orientation and contours of the bladder are altered and displaced and the uptake can be falsely regarded as pathological . on such occasions our case demonstrates one such unusual cause of bladder displacement , the location of which and its intense tracer uptake which can potentially mimic a pathology . cystocele is protrusion of bladder into or through the vagina and is radiographically defined as descent of the bladder base below the pubococcygeal line , which defines the level of pelvic floor . it is primarily caused due to weakening of pubocervical fascia due to child birth , aging or prior hysterectomy , other causes include obesity , heavy lifting and chronic constipation . the patient in our report had grade 3 cystocele as the bladder had bulged through the introitus . our case demonstrates how a commonly encountered clinical condition like cystocele can potentially mimic a sinister pathology on fdg pet scan . it also highlights how careful attention to the nature and intensity of fdg uptake and the anatomical information provided by ct can avoid potential pitfalls when fdg concentration is noted in a displaced and altered urinary system .
unexpected findings are seen on fdg pet / ct outside the primary site of abnormality . 
 such incidental findings are common in the genitourinary tract due to normal urinary excretion of fdg . 
 we report a case of incidentally detected grade 3 cystocele in a patient who underwent fdg pet / ct study for a suspected lung malignancy .