The gallbladder is affected by a large number of congenital anomalies, which may affect its location, number, size, or form. Some of these malformations are very rare and may lead to misdiagnosis.¹  The normal gall bladder lies in the gall bladder fossa on the inferior surface of the liver in between the right and left hepatic lobes maintaining a constant relationship to portahepatis ²  Ectopic gall bladder is a rare entity. Its incidence being 0.1%- 0.7% ³.

 Ectopic gall bladder can be located in various positions such as, intrahepatic, within the lesser omentum, retro duodenal, within falciform ligament, abdominal wall muscles and in thoracic cavity ^2,3. An ectopic gall bladder is a dangerous entity as it can lead to misdiagnosis. Different Imaging modalities can be used to help the surgeon to plan the proper approach to the ectopic gall bladder.² However, Ultrasonography is the most common investigation for evaluating orthotopic gall bladder, its role in the ectopic one is limited. On the other hand, hepatobiliary scan (HIDA scan), having a high physiological sensitivity to bile kinetics,  plays an important role in evaluating not only the orthotoipic gall bladder but also the ectopic one with the high detection accuracy. Here we present a case of suspected ectopic gallbladder prior to invasive drainage confirmed by hepatobiliary scan highlighting the importance of SPECT/CT HIDA scan in ectopic gallbladder..

    We present a case of 20 years old male patient presented to the ER with features of acute abdomen with history of surgical repaired  gastroschiasis  18 years ago with  no surgical  details.  CECT was performed and initially reported as incomplete intestinal obstruction with fluid collection in the epigastric region antro-inferior to the left hepatic lobe (fig.1).   Patient was shifted to the interventional radiology two days later for collection drainage. Pre procedure CT shows high density in the collection so possibility of vicarious excretion was suspected (fig. 2). The procedure was postponed , U/S pre and post meal was not conclusive so patient was referred to nuclear medicine department for HIDA scan for evaluation and rule out communication with the biliary system. Dynamic  HIDA scan was performed for 60 minutes one frame/min, low energy high resolution parallel collimator, matrix 64 x 64 followed by SPECT/CT Acquisition Single-photon emission computed tomography (GE Healthcare NM/CT 640, 120 steps, 20 s/step, matrix 128 x128. Low-dose  non-diagnostic computed tomography); axial, coronal and sagittal single-photon emission computed  tomography, computed tomography and fused images using xelerisis software.

  In  the dynamic images focal area of increase tracer uptake  after 9 minutes inferior to the left hepatic lobe  increase with time with partial excretion in the late dynamic study . Another area of increased uptake is noted in the gall bladder fossa after 17 minutes with good excretion in the bowel by the end of dynamic study (fig.3). SPECT/CT study showed location matching of the suspected collection with the focal area of increased tracer uptake other than the normal tracer uptake noted at the region of the orthotopic gallbladder.  So the diagnosis of an ectopic duplicated gall bladder was considered. ( fig.4).