This document presents a collection of 11 unusual hernia cases seen at a busy Emergency Department. For each case, the document summarizes the clinical history, imaging findings, diagnosis, pathogenesis, epidemiology, clinical presentation, and outcome. The cases include rare hernias such as bilateral Spigelian hernias, transdiaphragmatic intercostal hernia, superior lumbar hernia, retroperitoneal herniation of gastric diverticulum, incarcerated vesico-inguinal hernia, internal paraduodenal hernia, internal foramen of Winslow hernia, direct inguino-labial hernia, parastomal herniation of gallbladder, obturator hernia, and an

1. A Collection of unusual HerniasAug 11-14, 2010 Seattle, WAGabriel Werder, MDSyedJafri, MDSteven Wang, MDKathleen McCarroll, MDDepartment of RadiologyWilliam Beaumont HospitalRoyal Oak, Michigan

2. ObjectivesPresent a collection of unusual hernias from our busy Emergency DepartmentIllustrate imaging features of these various conditions in an unknown-case format Discuss the pathogenesis, epidemiology, clinical presentation, diagnosis, & outcome of the above conditions

3. Congenital or Acquired External Hernias Inguinal FemoralObturator SciaticSpigelianEpigastric UmbilicalParaumbilicalIntercostal

4. Internal HerniasParaduodenalTransmesenteric Foramen of Winslow Retroperitoneal

5. Iatrogenic HerniasIncisional VentralParastomal

6. Case 1: Clinical History 51-year-old male Abdominal pain No significant surgical history

7. Case 1: Diagnosis?

8. Case 1: Imaging FindingsBilateral defects between lineasemilunaris laterally & rectus muscle medially with fat- & bowel-containing hernia sacsNote appendix in right hernia sac

9. Case 1: Large Bilateral Spigelian HerniasPathogenesis Protrusion of intra-abdominal contents through a defect in Spigelianaponeurosis (between lineasemilunaris laterally & lateral edge of rectus abdominus muscle medially)Epidemiology In adults, ♂:♀ = 1:1; in children, ♂:♀ = 2:1 2% of anterior abdominal herniasPresentation Asymptomatic, intermittent abdominal pain, intestinal obstructionDiagnosis CT (although may also be detected on barium studies)Outcome Surgical management if symptomatic

10. Case 2: Clinical History 59-year-old malePleuritic chest pain; chronic cough No significant surgical history

11. Case 2: Diagnosis?

12. Case 2: Imaging FindingsPosterolateral defect between ribs with fat & splenic flexure in hernia

13. Case 2: TransdiaphragmaticIntercostal HerniaPathogenesis Herniation through both diaphragm & intercostal space Congenital Post-traumatic (remote) Associated with increased intrathoracic pressure Chronic cough, brass instrument use, glass blowing, weight lifting Associated with chest wall neoplasm/infection Epidemiology Fewer than 20 reported cases in literature, mostly post-traumaticPresentation Reducible palpable soft tissue mass over lower chest wall Positive cough impulseDiagnosis CT, chest radiograph, &/or ultrasound Differentiate from lumbar hernias, which are below 12th ribOutcome Surgical management

14. Case 3: Clinical History 78-year-old male Back pain & palpable mass No significant surgical history

15. Case 3: Diagnosis?

16. Case 3: Imaging FindingsLeft paraspinal abdominal wall defect allowing herniation of retroperitoneal contents into posterolateral subcutaneous tissues inferior to left 12th rib

17. Case 3: Superior Lumbar (Grynfeltt’s) HerniaPathogenesisHerniation through superior lumbar triangle (inverted triangle)Superior boundary: 12th rib/serratus posterior inferior/lumbocostal ligament Medial boundary: erector spinae Lateral boundary: internal abdominal oblique 20% congenital, 50-55% primary (aging), 25-30% secondary (surgery/trauma) Epidemiology Uncommon, approximately 300 cases reported in literature 95% of lumbar hernias are via superior lumbar triangle Typically occurs in elderly males & most commonly left-sidedPresentation Reducible palpable soft tissue with positive cough impulseDiagnosis Differentiate from intramuscular lipoma by clinical findings Differentiate from inferior lumbar (Petit’s) hernia & intercostal hernia by CTOutcome Incarceration in 25%, strangulation in 8% Surgical management if symptomatic

18. Case 4: Clinical History 84-year-old femaleEpigastric & back pain No significant surgical history

19. Case 4: Diagnosis?

20. Case 4: Imaging FindingsRound retroperitoneal structure containing air-fluid level, contiguous with stomach

21. Case 4: Retroperitoneal Herniation of Gastric DiverticulumPathogenesis Unknown, likely post-traumatic (remote)Epidemiology Rare, incidence unknownPresentationEpigastric pain, back pain, dysphagiaDiagnosis CTOutcome Surgical management if symptomatic

22. Case 5: Clinical History 73-year-old male Left groin pain, urinary frequency, hematuria No significant surgical history

23. Case 5: Diagnosis?

24. Case 5: Imaging FindingsUrinary bladder extending into left inguinal canal with surrounding inflammatory change

25. Case 5: Incarcerated Vesico-Inguinal HerniaPathogenesis Extension of urinary bladder (or bladder diverticulum) into inguinal canalEpidemiology Bladder involvement in 1-3% of inguinal herniasPresentation Symptoms of inguinal hernia often mask urinary symptomsDiagnosis Retrograde cystourethrogram, CT cystogram, CTOutcome Surgical emergency due to incarceration If no incarceration, surgical repair on a non-emergent basis

26. Case 6: Clinical History 38-year-old female Nausea, diarrhea, abdominal pain Medical history significant for recent postpartum status

27. Case 6: Diagnosis?

28. Case 6: Imaging FindingsAll small bowel in left upper abdominal quadrant with “stretching” of mesentery & inflammatory change

29. Case 6: Internal (Paraduodenal) HerniaPathogenesis Protrusion of bowel loops through abnormal mesenteric fossa or defectEpidemiology Overall incidence of internal hernias < 1% 2nd most common type of internal hernia (after transmesenteric) 75% left (via paraduodenal mesenteric fossa of Landzert) 25% right (via jejunalmesentericoparietalfossa of Waldeyer)PresentationPeriumbilical pain, abdominal distension, partial small bowel obstruction Diagnosis CT, upper GI, small bowel follow through Differentiate from closed loop SBO by presence of encapsulating membraneOutcome Bowel decompression & surgical repair

30. Case 6: Companion Case

31. Case 6: Internal (Paraduodenal) HerniaAll small bowel in left upper abdominal quadrant with circumscribed appearance & “stretched” mesenteric vessels

32. Case 7: Clinical History 55-year-old male Abdominal pain No significant surgical history

33. Case 7: Diagnosis?

34. Case 7: Imaging FindingsCecum abnormally positioned between liver hilum & stomach

35. Case 7: Internal (Foramen of Winslow) HerniaPathogenesis Protrusion of bowel behind hepatoduodenal ligament into lesser sac Riedel’s lobe is a risk factor Thought to direct bowel toward Foramen of WinslowEpidemiology Overall incidence of internal hernias < 1% Foramen of Winslow hernias account for 8% of internal herniasPresentation Abdominal pain, proximal bowel obstruction, jaundice (rarely)Diagnosis CT, upper GI, small bowel follow through, barium enema Differentiate from left paraduodenal hernia by absent encapsulating membrane Differentiate from cecalvolvulus by proximal bowel obstructionOutcome Bowel decompression & surgical repair

36. Case 8: Clinical History 55-year-old female Working diagnosis: pyelonephritis No significant surgical history

37. Case 8: Diagnosis

38. Case 8: Imaging FindingsDilated loops of small bowel with bowel entering labia via inguinal canal medial to inferior epigastric vessels (IEV)

39. Case 8: DirectInguino-Labial HerniaPathogenesisHerniation through floor of inguinal canal (Hesselbach’s triangle) Actual defect occurs in transversalis fascia Differentiate from indirect hernia (passes through internal inguinal ring)Epidemiology 75-80% of all hernias occur in inguinal regionDirect:Indirect = 1:5♂ > ♀ (both direct & indirect)Presentation Groin mass/pain, bowel obstructionDiagnosis CT, US, plain radiography, barium studies Differentiate from indirect hernia by relation to inferior epigastric vesselsOutcome Surgical management if symptomatic

40. Case 8: Companion Case

41. Case 8: Ovaries in IndirectInguino-Labial HerniasRound ligaments/ovaries enter inguinal canals lateral to IEV

42. Case 9: Clinical History 83-year-old female Abdominal pain Surgical history significant for right upper abdominal quadrant end-ileostomy

43. Case 9: Diagnosis?

44. Case 9: Imaging FindingsExtension of gallbladder into subcutaneous tissues adjacent to stoma

45. Case 9: ParastomalHerniation of GallbladderPathogenesis Iatrogenic defect at stoma permits herniation of abdominal contentsEpidemiologyParastomal hernia incidence estimated up to 30% Fewer than 10 reported cases involving gallbladder in literaturePresentation Pain, parastomal mass, stomal dysfunction, bowel obstructionDiagnosis Clinical findings, CTOutcomeParastomal hernia usually managed conservatively If surgery is necessary, relocating stoma preferred over local repair Gallbladder hernia usually treated by cholecystectomy/defect repair

46. Case 10: Clinical History 66-year-old female Medial right thigh pain Flexion relieves Abduction/extension/external rotation exacerbates No significant surgical history

47. Case 10: Diagnosis?

48. Case 10: Imaging FindingsAbnormal soft tissue attenuation structure between pectineus (superficial) & obturator (deep) muscles

49. Case 10: Obturator HerniaPathogenesis Herniation through obturator canal in superolateralobturator foramen Hernia sac extends between pectineus & obturator musclesEpidemiology Account for approximately 0.1% of hernias♂:♀ = 1:6-9 Mean age 82; age range 65-95 yearsPresentation Acute or recurrent small bowel obstructions (often partial)DiagnosisHowship-Romberg sign: abduction/extension/external rotation  pain Medial thigh pain due to irritation of obturator nerve Knuckle of bowel between pectineus & obturator muscles on CT Differentiate from femoral hernia by relation to pectineus muscleOutcome Bowel decompression & surgical repair 13-40% mortality rate

50. Case 10: Companion Case

51. Case 10: Obturator HerniaAbnormal soft tissue attenuation structure between pectineus (superficial) & obturator (deep) muscles

52. Case 11: Clinical History 81-year-old female Nausea & vomiting No significant surgical history

53. Case 11: Diagnosis?

54. Case 11: Imaging FindingsAbnormal soft tissue attenuation structure superficial to pectineus muscle; small bowel distension

55. Case 11: Femoral HerniaPathogenesis Herniation through femoral canal medial to femoral vein Hernia sac is superficial to both pectineus & obturator musclesEpidemiology 5-10% of all groin hernias; 30% in women; < 1% in children♂:♀ = 1:3Presentation Medial thigh mass inferior to groin crease ± bowel obstructionDiagnosis Knuckle of bowel superficial to pectineusmuscle on CT Differentiate from obturator hernia by relation to pectineus muscleOutcome Bowel decompression & surgical repair Incarceration rate 25-40% (8-12x more than inguinal hernia)

56. Case 12: Clinical History 56-year-old male Acute renal failure History significant for renal transplant

57. Case 12: Diagnosis?

58. Case 12: Imaging FindingsTransplant hydronephrosis with ureter entering left inguinal canal

59. Case 12: Transplant Uretero-Inguinal HerniaPathogenesisHerniation of transplant ureter into inguinal canalEpidemiology Rare, incidence unknownPresentation Urinary symptoms, groin painDiagnosisUreter extending into inguinal canal on CT, CTU, IVU, or nephrostogramOutcome Decompression with percutaneousnephrostomy Surgical repair of hernia defect

60. Case 12: Transplant Uretero-Inguinal HerniaPathogenesisHerniation of transplant ureter into inguinal canalEpidemiology Rare, incidence unknownPresentation Urinary symptoms, groin painDiagnosisUreter extending into inguinal canal on CT, CTU, IVU, or nephrostogramOutcome Decompression with percutaneousnephrostomy Surgical repair of hernia defectIn this case, the ureter was able to be freed from the inguinal canal percutaneously, following which an internal/external nephroureteral stent was placed (see next slide)

61. Case 12: OutcomeUreter being freed from inguinal canal percutaneously, followed by internal/external nephroureteral stent placement

62. Acknowledgements & Contact InformationThe authors acknowledge significant contributions from & extend their gratitude to the following individuals:Dr. Ali Shirkhoda Dr. Hugh KerrDivision of Body Imaging Division of Emergency RadiologyDepartment of Radiology Department of RadiologyWilliam Beaumont Hospital William Beaumont HospitalContact Information:Gabriel Werder, MDDepartment of RadiologyWilliam Beaumont Hospital3601 W Thirteen Mile RdRoyal Oak, MI 48073Gabriel.Werder@beaumont.edu