Radiodiagnosis Cases: Baker's Cyst & Müllerian Duct Anomalies

1. TEACHING FILES Dr Mayur R2, Dr Payal R1 Dept of Radiodiagnosis Medical College & S S G Hospital, Baroda ( 31-12-07 )

2. CASE 1

3. 56yr M, presented with a gradually progressing swelling in posterior region of knee & discomfort.

6. D/D OF CYSTIC LESION AROUND THE KNEE • Baker’s cyst • Popliteal aneurysm • Ganglion • Meniscal cysts • Collection or abscess

7. Backer or Popliteal cyst • It represents fluid distention of a bursa (gastrocnemiosemimembranosus bursa) between the gastrocnemius and semimembranosus tendons via a communication with the knee joint. • Although c/as the gastrocnemiosemimembranosus bursa, it represents a composite of two bursae: • a bursa anterior to the medial gastrocnemius tendon (the subgastrocnemius bursa) and • a bursa between the tendons of the gastrocnemius and semimembranosus tendons

8. most common associations include joint effusion, meniscal tear, and degenerative joint disease • MRI gives the typical appearance of the fluid containing structure, with low SI on T1W & high SI on T2W. • Occasionally the cyst can leak fluid into the calf and cause calf swelling, tightness & pain ( rupture backer cyst ). This may even simulate a calf DVT (deep vein thrombosis). It is easily diagnosed by a careful examination and an ultrasound scan or on MRI.

9. Baker’s cyst

10. 60-year-old woman with Baker's cyst. Axial sonogram of posterior knee shows Baker's cyst (arrowheads) with fluid (solid straight arrow) between semimembranosus tendon (curved arrow) and medial gastrocnemius tendon (open arrow). Note subgastrocnemius component (asterisk) of Baker's cyst.Axial proton density-weighted MR image with fat saturation reveals Baker's cyst (arrowheads) with fluid (black arrow) between semimembranosus tendon (curved white arrow) and medial gastrocnemius tendon (open arrow). Note subgastrocnemius component (asterisk) of Baker's cyst. M = medial gastrocnemius muscle.

11. 15-year-old boy with Baker cyst. Sagittal sonogram of posterior knee shows Baker's cyst (arrowheads). Note septation (solid arrow). Open arrows = medial gastrocnemius tendon, T = tibia. Sagittal proton density-weighted MR image reveals Baker's cyst (arrowheads). Note septation (solid arrow). Open arrows = medial gastrocnemius tendon.

12. Meniscal cysts • It is a accumulation of fluid in association with an adjacent meniscus tear extending from the joint surface to its outer border. • Joint fluid is forced in to the cyst when patient walks & accumulates at the meniscocapsular margins. • When a Meniscal cysts is incidentally detected on the MRI, a careful attention must be paid to the adjacent meniscus.

13. 13-year-old girl with meniscal cyst. Sagittal proton density-weighted MR image reveals meniscal cyst (curved arrow) in continuity with meniscal tear (straight arrow). Axial proton density-weighted MR image with fat saturation reveals meniscal cyst (curved arrow) with signal intensity of fluid without extension between semimembranosus tendon (undulating arrow) and medial gastrocnemius tendon (arrowhead).

14. 39-year-old man with myxoid liposarcoma.Axial T1-weighted MR image reveals heterogeneous, predominately intermediate-signal-intensity lesion in posterior aspect of knee jt(arrowheads). Axial proton density-weighted MR image with fat saturation reveals predominately high-signal-intensity mass (arrowheads). Note lack of extension between semimembranosus tendon (solid arrow) and medial gastrocnemius tendon (open arrow).

15. Treatment • It is best treated by treating the cause of the excess fluid (fixing the cartilage tear or arthritis) and then the Bakers cyst usually fades away. • A large and persistent Bakers cyst may require surgical removal which is done through an incision across the back of the knee, although it can sometimes be removed by arthroscopic surgery.

16. CASE 2

17. 25 years old female. • H/O Primary infertility, referred for pelvic ultrasound. • No other complaints. • Past & family histories are not significant. • P/V :NAD

18. prominent fundal cleft with persistently seperated upper uterine segment with partial fusion of lower uterine segment.

20. Diagnosis • Uterus bicornis unicollis

21. Discussing the Müllerian duct anomalies • Two paired müllerian ducts ultimately develop into the structures of the female reproductive tract. • The structures include the fallopian tubes, uterus, cervix, and upper two thirds of the vagina. • The ovaries and lower one third of the vagina have separate embryologic origins not derived from the müllerian system. • Müllerian duct anomalies are categorized most commonly into 7 classes according to the American Fertility Society (AFS) Classification Scheme as follows:

22. Class I (hypoplasia/agenesis) • It includes uterine/cervical agenesis or hypoplasia. • The most common form is the Mayer-Rokitansky-Kuster-Hauser syndrome, which is combined agenesis of the uterus, cervix, and upper portion of the vagina. • Patients have no reproductive potential. • On USG & MRI: • Findings of agenesis include absence of the cervix and/or uterus with a blind-ending vagina. In uterine hypoplasia, the endometrial cavity is small with a reduced intercornual distance (<2 cm).

23. Class II (unicornuate uterus) • Result of complete, or almost complete, arrest of development of one of the müllerian duct. • On USG & MRI: • The unicornuate uterus appears banana shaped without the usual rounded fundal contour and triangular appearance of the fundal cavity. Uterine zonal anatomy is normal. • If obstructed, a rudimentary horn with functioning endometrium may present as a complex hemorrhagic cystic structure. ( blood or blood products on MRI )

24. Unicornuate uterus. Schematic diagram shows a one half of the uterus ( rudimentary horn ) arising from the contralateral müllerian duct. Axial MRI image shows a banana shape single uterine horn with normal appearing endometrial cavity and cervix on left side.

25. Class III (didelphys uterus) • This anomaly results from complete nonfusion of both müllerian ducts. • The individual horns are fully developed and almost normal in size. • Two cervices are inevitably present. • A longitudinal or transverse vaginal septum may be noted. • On USG & MRI: • Two separate normal-sized uteri and cervices are seen. A septum may be visualized extending into the upper vagina. • The 2 uterine horns are usually widely splayed, and endometrial and myometrial zonal widths are preserved.

26. Didelphys uterus. Complete separation and full development of both müllerian ducts is noted. (a) Two vaginas and 2 cervices; (b) 2 distinct cervices; (c) 2 uterine horns are widely splayed; (d) cross section of uterine bodies and cervices.

27. Class IV (bicornuate uterus) • A bicornuate uterus results from partial nonfusion of the müllerian ducts. • On US: • demonstrate 2 uterine cavities with normal endometrium. • a concave fundus with a fundal cleft greater than 1 cm. This has been shown to be a reliable means of distinguishing bicornuate from septate uteri. • An increased intercornual distance (>4 cm) may be observed. • The septum separating the 2 horns demonstrates echogenicity identical to that of myometrium. • On MRI : • The tissue separating the 2 horns demonstrates signal intensity identical to myometrium on all pulse sequences.

28. Bicornuate uterus. Schematic diagram shows the partial fusion of the lower uterine segment and persistently separated upper uterine segments with a prominent fundal cleft (>1 cm). On hysterosalpingography films, shows the widened intercornual distance (>4 cm) and the widened intercornual angle (>60°)

29. In the bicornuate uterus if the central myometrium extend to the level of the internal cervical os its results inbicornuate unicollis uterus

30. In the bicornuate uterus, if the central myometrium extend to the level of external cervical OS then it results in Uterus bicornis bicollis distinguished from didelphys uterus because it demonstrates some degree of fusion between the 2 horns, while in classic didelphys uterus, the 2 horns and cervices are separated completely. In addition, the horns of the bicornuate uteri are not fully developed; typically, they are smaller than those of didelphys uteri.

31. Bicornuate uterus. On MRI image shows the midline uterine external fundal cleft (superior border) has a depression greater than 1 cm which excluding septate uterus. This image is of bicornuate bicollis, since 2 cervices are present.

32. Class V (septate uterus) • A septate uterus results from failure of resorption of the septum between the 2 uterine horns. • The septum can be partial or complete, in which case it extends to the internal cervical os. ( myometrium or fibrous ) • Differentiation between a septate and a bicornuate uterus is important because septate uteri are treated by using transvaginal hysteroscopic resection of the septum, whereas surgery is indicated for the bicornuate uterus via abdominal approach (metroplasty) • On US & MRI: • The outer fundal contour is convex, flattened, or mildly concave (fundal cleft <1 cm) • The intercornual distance is usually normal (<4 cm) • uterine cavity -- small. • A more reliable means for differentiating the septate uterus from bicornuate uterus is to examine the fundal contour

33. Septate uterus. Schematic diagram shows a normal uterine contour with Midline thin and linear septum usually < 1 cm & seen as an extension of the uterine myometrium.

34. MRI image of septate uterus. Shows a thin, fibrous septum that cannot be resolved distally at the fundus. T2 fast spin-echo MRI image acquired in the oblique plane along the long axis of the uterus shows a flat or slightly concave outer fundal contour (superior border), which is sufficient to make the diagnosis of septate uterus.

35. Class VI (arcuate uterus) • An arcuate uterus has a single uterine cavity with a convex or flat uterine fundus, the endometrial cavity, which demonstrates a small fundal cleft or impression (1.5 cm). The outer contour of the uterus is convex or flat. • This form is often considered a normal variant. • it is not clinically significant because arcuate uterus has no significant negative effects on pregnancy outcome.

36. Arcuate uterus. Mild thickening of the midline fundal myometrium resulting in fundal cavity indentation but normal outer fundal contour. Some authors consider it a normal variant. It is not associated with an increased risk of obstetric/gynecologic complications.

37. Class VII (diethylstilbestrol-related anomaly) • The uterine anomaly is seen in the female offspring of as many as 15% of women exposed to DES during pregnancy. • Abnormal findings in female fetus includes: • uterine hypoplasia and a T-shaped uterine cavity. • abnormal transverse ridges, hoods, stenoses of the cervix, and • adenosis of the vagina with increased risk of vaginal clear cell carcinoma. • MRI may detect this abnormality as a hypoplastic uterus. Typically, the DES-related anomaly is diagnosed confidently using HSG

38. Schematic diagram and hystrosalpingography flims shows a typical T-shaped uterus configuration of the uterine cavity in a patient with diethylstilbestrol-exposed uterus which is due to myometrium hypertrophy and hypoplastic utri.

39. APPROACH Two endometrial Cavities do not fuse Two endometrial cavities Fuse lower down. • didelphys. • bicornis bicollis. • Septate. • Bicornis unicollis. • subseptate Separating myometrium Separating myometrium > 1 cm in bicornis bicollis. < 1cm in septate & didelphys. • 1 cm in Bicornis unicollis. < 1 cm in subseptate Do P/V examination.

40. CASE 3

41. A 5yr old girl presented with a h/o lethargy & cough since 4mth. • On examination pt was anaemic and PEM gr 3. • Has a raised ESR.

43. The Dense Metaphyseal Band Sign • Dense metaphyseal bands, less commonly known as dense metaphyseal lines, transverse bands, or "lead lines," indicate radiopaque bone (thicker than the adjacent diaphyseal cortex) at the metaphysis of growing bone, particularly at the wrists and knees.

44. Anteroposterior radiograph of the wrist obtained in a 2-year-old boy reveals a dense metaphyseal band (arrow) in the distal radius, without flaring or cupping. The distal ulna is unremarkable. By excluding more serious causes, this finding was proved to be a normal variant.

45. Anteroposterior radiograph of the knees in a 4-year-old girl reveals very dense metaphyseal bands in the distal femurs and proximal tibias (arrows) as well as in the proximal fibulas (arrowheads). This patient was encephalopathic and anemic and had a lead level of 60 µg/dL (2.898 µmol/L) at admission.

46. In order of decreasing frequency, the causes of a dense metaphysis include • Normal variance ( most common cause) • Plumbism, • Treated leukemia, • Healing rickets, • Other heavy metal (arsenic, bismuth, mercury) poisoning, • Recovery from scurvy, vitamin D hypervitaminosis, • Congenital hypothyroidism, hypoparathyroidism, and • Transplacental infections (eg, toxoplasmosis, rubella, cytomegalovirus, and herpes).

47. Leadpoisoning in infants and children may be diagnosed in screening programs, clinically, or radiographically. • Plumbism in children can be traced to pica (eg, dirt eating), acute ingestion of lead-based paints, consumption of home remedies, inhalation of toxic fumes, and rarely, absorption of lead-containing material from metallic or bullet fragments in a serous cavity or joint. • In general, lead lines indicate past lead exposure and correlate with a blood lead level of 50 µg/dL. • The presence of a dense metaphyseal band at the proximal fibula is a strong indication of plumbism, although the mechanism related to the lead toxicity remains unknown.

48. The presence of dense metaphyseal bands strongly supports the diagnosis of lead toxicity. • With treatment or cessation of lead exposure, the lead band will demonstrate an apparent migration into the metadiaphysis because of normal new bone growth. • Accordingly, when the lead level returns to normal, the metaphyseal band will gradually decrease in radiopacity and disappear in approximately 4 years.

49. Anteroposterior abdominal radiograph reveals multiple metallic particles (arrows) confined to the colon in a 22-month-old boy with acute lead ingestion.

50. Knee of a 3-year-old girl with leukemia. Anteroposterior radiograph shows formation of thin, dense metaphyseal bands (growth recovery lines) In femur and tibia and less so In fibula, owing to cycles of chemotherapy. • Normal knee of a 2 month- old boy. Anteroposterlor radiograph shows normal sclerotic lines of distal femoral and proximal tiblal metaphyses. These should not be confused with bands caused by chronic Ingestion of heavy metals. Note absence of sclerosis of proximal part of flbula.