ovarian torsion results from the rotation of the ovary about its pedicle , to an extent that the ovarian arteries and or veins are obstructed .
this condition generally results from a benign tumor of the ovary and usually occurs in younger women .
clinical signs include sudden onset of lower abdominal pain associated with other constituitional symptoms like nausea and vomiting . in 1896 , fredrick krukenberg described a new type of ovarian tumor .
this tumor was later identified as a malignancy in the ovary from a primary lesion in the gastrointestinal tract , and named 
presentation of a krukenberg tumor with ovarian torsion is a rare event which we will detail in this case report .
a 43-year - old female , ( gravida 2 , para 2 ) presented to the emergency department ( ed ) with an acute onset of right lower quadrant abdominal pain , which was severe and progressive in intensity . the pain was episodic , with associated diarrhea .
gynecological examination revealed a large fixed fluctuant abdominal mass within the pelvis , extending above the umbilicus .
working diagnosis in the ed was cystic abdominal mass of unknown origin , likely ovarian .
a contrast - enhanced ct scan of the abdomen and pelvis was ordered and revealed a large poorly enhancing , predominantly cystic mass arising from the left adnexa , measuring 21.6 cm craniocaudal  11.7 cm ap ( anteroposterior )  22.8 cm transverse , with numerous thin non - enhancing septations and small vessels coursing throughout the lesion [ figure 1 ] .
the mean attenuation value of the mass ranged from 814 hounsfield units , confirming its predominantly cystic nature .
contrast - enhanced coronal ct images of the abdomen and pelvis , demonstrate a large predominantly cystic left adnexal mass containing multiple septations almost completely occupying the abdomen ( black arrow ) .
the twisted vascular pedicle in the left lower quadrant demonstrates a whirlpool sign ( white arrows ) ( similar to what is described in the ultrasound literature ) .
the mass demonstrated a discrete vascular pedicle in the left hemi - pelvis in the vicinity of the round ligament of the ovary with enhancing engorged vessels in the pedicle .
there was a discrete  vascular swirl sign appreciated at the left ovarian vascular pedicle , suggesting that this represented a massively enlarged left ovary with a significant torsion of greater than 270 degrees .
these findings helped clinch the diagnosis of an ovarian torsion [ figure 4(a - d ) ] . a second large mass measuring 5.3 cm craniocaudal  6.5 cm ap  5.4 cm transverse , originating from the contralateral right ovary with enhancing solid rind and central hypoattenuation , representing the right ovarian krukenberg tumor [ figure 2 ]
( a ) contrast - enhanced axial and ( b ) coronal ct images through the pelvis demonstrate a solid heterogeneously enhancing right - adnexal mass , with a thick enhancing rind , consistent with a krukenberg tumor ( arrow ) .
the presence of bilateral ovarian masses strengthened the initial diagnosis of krukenberg tumors and an attempt was made to assess the primary lesion .
there was an irregular plaque - like , mildly enhancing , mass - like area in the mid - gastric body , along the lesser curvature , relating to a primary gastric malignancy [ figure 3 ] .
other relevant findings included peritoneal / serosal implants and mild right hydroureteronephrosis due to extrinsic compression of the right ureter from the right adnexal mass .
contrast - enhanced axial ct at the level of the liver reveals a focal nodular thickening of the gastric body along the greater curvature and antrum ( arrow ) suggestive of gastric carcinoma that was subsequently confirmed by histopathology .
four contiguous sagittal images showing a discrete  swirl sign at the vascular pedicle ( white arrows ) at the base of the large left ovarian mass , consistent with the torsion of ovarian krukenberg tumor at its pedicle .
the patient underwent esophagogastroduodenoscopy / colonoscopy showing a large friable ulcer located in the posterior wall of the stomach measuring approximately 10 cm , extending to both the lesser and greater curvature , showing a concern for malignancy [ figure 3 ] .
the patient subsequently underwent an exploratory laparotomy , bilateral salpino - oophrectomy , total gastrectomy , and esophagojejunostomy . a gross pathological examination revealed a 26 cm left ovarian tumor , smaller right ovarian tumor , disseminated metastases in the peritoneum , and gastric tumor within the body of the stomach .
microscopic pathology from the gastric specimen revealed a poorly differentiated gastric adenocarcinoma of the signet cell type , while ovarian pathology showed metastatic bilateral krukenberg tumors from the gastric carcinoma , with signet cell histology similar to the primary tumor [ figure 5 ] . a gross image of bi - valved left ovary weighing 2475 g and measuring 26  21  6 cm .
note the large hemorrhagic area on one end of the ovary ( white arrow ) , measuring 11  5  2.5 cm , and other smaller areas of hemorrhage within the solid ovarian mass .
( the deceptive cystic appearance on ct was due to a poor flow , with large areas of infarction ) .
these tumors are relatively uncommon and account for only one to two percent of all ovarian tumors .
these tumors primarily originate from carcinomas of the gastrointestinal tract and less commonly from the breast , gallbladder , colon , appendix , or pancreas .
microscopically , these tumors are characterized by mucin - secreting signet ring cells in the ovarian tissue and in the primary tumor site .
a review of literature indicates that 35 to 45% of the patients were younger than 40 years of age , with an average range of 40 to 46 years . although unanswered for a long time , it is now apparent that a retrograde lymphatic spread is the most common route for the spread of metastasis of gastric carcinoma to the ovaries .
the common presenting symptoms are related to the ovary and include abdominal pain and distension due to the bilateral , often large ovarian masses .
in addition , ascites is a common presentation in the krukenberg tumor and usually reveals malignant cells .
however , there has been a reported case of bilateral krukenberg tumors with benign ascites and right hydrothorax that revealed no malignant cells .
this is known as pseudo - meig syndrome , in contrast to the meig syndrome , which presents with a triad of benign ovarian tumor , ascites , and right - sided hydrothorax . in general ,
patients with a krukenberg tumor have a poor prognosis , with most patients averaging two years life expectancy , with a median survival time of 14 months .
studies have shown that prognosis is poor when the primary tumor is identified after metastasis of the cancer to the ovaries .
our case is unusual in that , the initial presentation of a gastric malignancy was acute ovarian torsion due to an ovarian krukenberg tumor acting as a lead point for torsion .
ovarian torsion is the twisting of an ovary on its ligamentous supports and can result in a compromised blood supply .
adnexal torsion is a term that is inclusive of either the ovary , fallopian tube , or both .
concomitant ovarian and tubal torsion has been shown to occur in up to 67% of the cases of adnexal torsion .
the main sonographic features of an ovarian torsion include a morphologically abnormal ovary , with or without ovarian blood flow .
the presence of blood flow within the ovary does not exclude ovarian torsion , it suggests that the ovary is viable and can be salvaged with surgery . as this patient presented to the er with severe abdominal pain and a significant increase in abdominal girth , the first imaging study ordered in the ed was a contrast - enhanced ct of the abdomen and pelvis , due to suspected malignancy or any other acute abdominopelvic process , thus bypassing the typical first line abdominopelvic ultrasound , to save time .
computed tomography is usually used as an adjunct modality when diagnosis is not straightforward on ultrasound and also when a wider field of view is needed , as in the case of our patient .
computed tomography features commonly suggestive of ovarian torsion on magnetic resonance imaging ( mri ) , the appearance of the krukenberg tumor is dependent on the degree of stromal overgrowth and mucin production .
dense stromal reaction gives a hypointense signal and mucin material usually gives a hyperintense signal on t2w images .
the presence of hypointense solid components within an ovarian solid mass is a characteristic , but a nonspecific finding for krukenberg tumors .
although the patient was in the average age range for krukenberg tumors , benign ovarian neoplasms and benign pathologies are typically more common .
currently , in radiology literature , there are no reported cases of krukenberg tumors presenting to the ed with acute ovarian torsion .
although uncommon , krukenberg tumors should be considered in the differential diagnosis of ovarian torsion , in addition to benign entities such as mature cystic teratoma .
 ovarian torsion is the fifth most common gynecological surgical emergency . 
 ovarian torsion is usually associated with a cyst or a tumor , which is typically benign . 
 the most common is mature cystic teratoma . 
 we report the case of a 43-year - old woman who came to the emergency department with rare acute presentation of bilateral krukenberg tumors , due to unilateral ovarian torsion . in this case report 
 , we highlight the specific computed tomography ( ct ) features of ovarian torsion and demonstrate the unique radiological findings on ct imaging . 
 metastasis to the ovary is not rare and 5 to 10% of all ovarian malignancies are metastatic . 
 the stomach is the common primary site in most krukenberg tumors ( 70% ) ; an acute presentation of metastatic krukenberg tumors with ovarian torsion is rare and not previously reported in radiology literature . 
INTRODUCTION
CASE REPORT
DISCUSSION