PRIMARY EPIPLOIC APPENDAGITIS: Clinical, US and CT Findings in 15 cases

Tai Van Le, Tai Anh Vo, Hai Thanh Phan, MD
MEDIC Medical Center, HCM City, Vietnam

ANATOMICAL REVIEW

Epiploic appendages are small peritoneal pouches that arise from the colon composed of fat tissue and blood vessels, 0.5 – 5 cm long. There are about 100 epiploic appendages (1).
Normal epiploic appendages are easily seen in cases of ascites at US and CT (2,3).


INTRODUCTION

Primary epiploic appendagitis (PEA) is a rare entity that usually mimicks others such as diverticulitis, appendicitis, right-sided segmental omental infarction (2,5,6,10).
Causes of PEA: torsion, spontaneous venous thrombosis (2,3,4,7,8,9,10).
vComplicated diverticulitis and acute appendicitis require surgical operation.
US can be used to help diagnose this entity in correlation with clinical and CT findings.

OBJECTIVE

To describe appearance at US of primary epiploic appendagitis (PEA) in correlation with CT findings, and evolution of PEA with conservative treatment.
To differentiate PEA requiring no surgery from other surgical entities.

MATERIALS & METHODS

All patients with sudden onset of acute abdominal pain were chosen for US exam.
From 2000 – 2003: 15 patients, 8 male and 7 female, age 8 – 67 (mean 41), suspected of having primary epiploic apppendagitis (PEA).
Ten cases were examined by US alone (n= 10), 5 cases by US & CT (n = 5).
R/ abd. pain: 2 cases (1 RUQ, 1 RLQ). L/ abd. pain: 13 cases, 1 of which had a palpable mass.
US criteria for diagnosis: a small, ovoid, solid, hyperechoic and non-compressible mass (4).
Based on CT findings: inflamed fat tissue adjacent to colon (2,3,4,7,8,9,10).
US machine with curve or linear probe (3.5 – 7.5 MHz), Toshiba SSH 250A & Aloka SSD Prosound 4000.

RESULTS

Position by US: A case was anterolateral to the ascending colon near cecum (Fig.6), 1 case adjacent to hepatic colonic flexure (Fig.5). Thirteen cases (n= 13): anterior or antero-lateral to the descending colon, 1 case located near splenic colonic flexure, 12 cases near sigmoid colon (Fig. 2,3,4).
US findings: In all cases, US detected an ovoid, solid, hyperechoic, and non-compres sible mass, sized 3 – 5 cm (Fig. 2,3,4,5,6).
CT findings: determined there was hyper-attenuating, inflamed fat tissue adjacent to colon (FIG. 2,3,4,6).
Laboratory Findings: Slightly elevated ESR. No or mild leucocytosis.
Clinical symptoms decreased after 7 – 12 days of medical treatment (analgesic, antibiotic) and disappeared completely after 2 weeks.

DISCUSSIONS

Clinical features: sudden & local abdominal pain with rebound tenderness; fever & diges- tive disorder (+/-); WBC & ESR mildly or not elevated.
US: a small, ovoid, and solid mass that was hyperechogenic, noncompressible & painful on palpation next to the descending/ ascending colon. This is similar to the literature.
CT: hyper-attenuation of fat tissue adjacent to colon.
In a study of Rioux et al (1994), epiploic appendagitis is self-limited and self-regressed, requiring only analgesics without surgery (4).
Clinical symptoms decrease after 7 – 12 days, and completely disappear after 2 weeks.
Different diagnosis: Omental infarction, diverticulitis, acute appendicitis.
Omental Infarction: rare, affects mostly adults, vascular occlusion common cause; most often RLQA at the level of umbilicus; also self-limited and autoreg- ressed.
•US: large-sized (> 5 cm).
•CT: heterogeneous attenuation (5,6).

In 2 cases of Right abdominal pain, clinicians suspected of acute appendicitis whereas US: PEA, regressed under conservative treatment and disappeared completely (Fig. 5,6).

CONCLUSIONS

PEA has characteristic US features.
PEA is not difficult to diagnose by US in combination with CT and clinical findings. CT determines there is inflamed fat tissue adjacent to colon.
PEA is self-limited, auto-regressed, and requires no surgery. This helps to prevent unnecessary surgical operation.

REFERENCES

1.Lorenzo E. Derchi. Appendices Epiploicae of the Large Bowel: sonographic Appearance and differentiation from peritoneal seeding, J Ultrasound Med 7:11-14, 1988
2.Ajay K. Singh, MD. Acute Epiploic Appendagitis and Its Mimics, RadioGraphics 2005;25:1521-1534
3.Patrick M. Rao. Primary Epiploic Appendagitis: Evolutionary Chang in CT Appearance, Radiology 1997;204:713-717
4.Rioux M, Lang P. Primary epiploic appendagitis: clinical, US, and CT findings in 14 cases. Radiology 1994; 191:523-526
5.Puylaert. Right-sided Segmental Infarction of the Omentum: Clinical, US, and CT Findings: Radiology 1992; 185:169-172
6.Matteo Baldisserotto, Omental Infarction in Children: Color Doppler Sonography Correlated with Surgery and Pathology Findings, AJR 2005; 184:156-162
7.Rathan Subramaniam. Acute appendagitis, emergency presentation and computed tomographic appearances, Emergency Medicine Journal 2006
8.Patrick M. Rao. Case 6: Primary Epiploic Appendagitis, Radiology. 1999;210:145-148.
9.Ajay K. Singh. CT Appearance of Acute Appendagitis, AJR 2004; 183:1303-1307
10.Karen M. Horton, CT Evaluation of the Colon: Inflammatory Disease, Radiographics. 2000;20:399-418.

Case report: NHỒI MÁU MẠC NỐI LỚN BÊN PHẢI

BS lê Văn Tài

BS Trần Lãm

Trung Tâm Y Khoa MEDIC

I. BỆNH ÁN

Bệnh nhân nữ 55 tuổi, đau HSP 1 tuần, không nôn ói, tiêu tiểu bình thường. Nhập viện điều trị 5 ngày, Siêu âm nghĩ bướu mỡ. Sau đó khám BS tư, bệnh nhân được chuyển đến MEDIC siêu âm. Kết quả siêu âm: nghĩ nhồi máu mạc nối lớn bên phải (H1A,1B). CT xác chẩn nhồi máu mạc nối lớn bên phải (H1C,1D,1E).

Điều trị : Kháng sinh, kháng viêm, giảm đau sau 2 tuần hết đau. Siêu âm sau 2 tuần cấu trúc nhồi máu nhỏ lại (H2A), sau 10 tuần nhỏ hơn nhiều và có co rút do xơ hoá (H2B, 2C).

II. BÀN LUẬN

Tần suất:

Hiếm, 85% ở người lớn, 15% ở trẻ em, nam nhiều hơn nữ (2).

Bệnh sinh:

Xoắn: nguyên phát, thứ phát do thoát vị, nang, sẹo mỗ, bướu (2).

Nguyên phát: nguyên nhân không rõ, có thể do thay đổi có nguồn gốc phôi thai kết hợp với bất thường động mạch gây giảm tưới máu phần dưới phải mạc nối lớn. Tĩnh mạch dài, cong quẹo (kinking) kết hợp với tăng áp lực ổ bụng đột ngột, sung huyết mạch máu sau ăn quá no (1,3).

Giải phẩu bệnh: sung huyết, xuất huyết, huyết khối tĩnh mạch, hoại tử mỡ và tẩm nhuộm tế bào viêm (1,2,3).

Lâm sàng:

- Đau đột ngột bụng (P), thường đau bụng dưới, đa phần có phản ứng thành bụng khu trú (1, 3), hay đau bán cấp (1), có thể kèm rối loạn tiêu hoá, tiểu khó, sốt nhẹ (2), nôn hiếm (1).
- Có thể sờ thấy khối nhưng ít (1).

Xét nghiệm: BC bình thường, ở giới hạn trên hay tăng nhẹ (1, 2), VS tăng (1).

Siêu âm

- Echo dầy thường không đồng nhất, có thể có echo kém bên trong, giới hạn có thể không rõ, oval, đè đau không xẹp, như cái bánh (cakelike) (1,2).

- Vị trí: giữa thành bụng trước và đại tràng ngang, đại tràng lên, thường ở mức ngang rốn, dính thành bụng trước (1,2,3).
- Kích thước: 3 – 15 cm (1).
- Echo kém
- Một số trường hợp có dạng hình ống bít 1 đầu như ruôt thừa viêm (2).
- Color Doppler: có thể có mạch máu (2).

CT

- Hình oval, tam giác. Tăng đậm độ không đồng nhất (mật độ mỡ - heterogeneous fatty mass)(1,2,3).
- Vị trí: giữa thành bụng trước và trước đại tràng ngang, đại tràng lên (1,2,3).

Chẩn đoán phân biệt:

- Viêm ruột thừa
- Viêm bờm mỡ đại tràng
- Viêm túi thừa.

Diễn tiến:

- Tự khỏi (self-limited), co rút do xơ hoá (fibroblastic reaction) (1,3).
- Dính vào ruột gây tắc ruột, áp- xe (3).

Điều trị:

- Bảo tồn: giảm đau, theo dõi lâm sàng, siêu âm, khỏi sau 2 tuần (1,3).

- Phẩu thuật: vì một số trường hợp sau điều trị bảo tồn có di chứng dính vào ruột gây tắc ruột nên phẩu thuật cắt bỏ phần mạc nối nhồi máu (2,3).

III. KẾT LUẬN

- Nhồi máu mạc nối lớn bên (P) có bệnh cảnh lâm sàng như Viêm ruột thừa. Có hình ảnh siêu âm, CT khá đặc trưng.
- Điều trị kinh điển là phẩu thuật, Tuy nhiên theo 1 số tác giả có thể điều trị bảo tồn không cần phẩu thuật.

Tài liệu tham khảo
1. Puylaert JB. Right-sided segmental infarction of the omentum: clinical, US, and CT findings. Radiology 1992;185:169 -172
2. Matteo Baldisserotto et al. Omental Infarction in Children: Color Doppler Sonography Correlated with Surgery and Pathology Findings. AJR 2005; 184:156-162
3. J. Damien Grattan-Smith et al. Omental Infarction in Pediatric Patients: Sonographic and CT Findings. AJR 2002; 178:1537-1539

ACUTE COLONIC UNCOMPLICATED DIVERTICULITIS CLINICAL, ULTRASOUND FINDINGS TO COMBINE WITH CT IN 22 CASES

Tai Van Le M.D

Nhan Vo Nguyen Thanh M.D

Hai Thanh Phan M.D

Medic Medical Center, HCM City, Vietnam

INTRODUCTION
Acute abdominal pain with rebound tenderness, particularly in cases of right-sided abdominal pain which are usually underwent surgery because of almost cases of acute appendicitis. However, acute colonic uncomplicated diverticulitis (ACUD), primary epiploic appendagitis, right-sided segmental infarction of omentum could be conservative treatment unnecessary operation. What role of ultrasound has in the diagnosis? Consequently, how to approach acute colonic uncomplicated diverticulitis that has been considered.

OBJECTIVE
The purpose of this study is to describe the sonographic appearance of acute colonic uncomplicated diverticulitis (ACUD), clinical evolution in correlation with conservative therapy. How to improve the accuracy of diagnosis of ACUD. Role of the sonographic appearance of normal colon (haustra pattern appearances) in detecting diverticulitis.

MATERIALS & METHODS
From December 2007 to January 2008, prospectively, 22 cases were suspected acute colonic uncomplicated diverticulitis with ultrasound, 17 male and 5 female, age: 22 – 70 year-old, (mean age 44 year-old), 19 cases of right abdominal pain, 3 cases of left abdominal pain, almost cases with rebound tenderness. All patients were performed with graded compression of Puylaret (1), 12 cases combining with CT.
Ultrasound scans of total colon thanks to normal colon which have haustra pattern appearaces. In practically, the wall of colon containing diverticulitis which became thickening due to reactive inflammation and to lose haustra pattern appearances. However, it could to recognize if there was the continuity with normal colon which has haustra pattern appearances. Thickening of fatty tissue surrounding colon is the important sign that suggests there are inflammation adjacent to colon.
The steps should to do for discover of ACUD (Figure 2): Firstly, to survey total colon to look for segmental colon with wall thickening, then to discover whether there is thickening of fatty tissue adjacent to it, after that detecting ACUM inside fatty tissue. ACUD is small hyperechoic lesion in or adjacent to colonic wall with or without shadowing, or hypoechoic lesion which could to open into colonic lumen. Characteristic ultrasound finding is similar to the appearance of thyroid glands with transverse section so-called “thyroid in the abdomen” appearance (2).
Aloka SSD Prosound 4000, convex probe with frequency 3.8 MHz, and MSCT of Toshiba were used.

RESULTS

Among twenty-two cases were suspected of ACUD, a case with post-operated diagnosis was acute appendicitis, twenty-one cases were true of ACUD (95%) in which ten cases of the cecum (47%) (Figure 3, 6), seven cases of ascending colon (33%) (Figure 2, 4), a case of transverse colon (5%), two cases of descending colon (10%) (Figure 5), a case of sigmoid colon (5%). There was a case of diverticulitis of the cecum with position of the cecum above umbilical level (Figure 6).

Ultrasound revealed a part of colon with thick wall and inflammation of pericolonic fatty tissue in which there was small hyperechoic lesion with or without shadowing that had findings similar to “thyroid in the abdomen” appearance, noncompressible and tenderness, 6 – 15 cm in diameter, 10 – 20 cm long (Figure). Color Doppler could to reveal hyperemia intracolonic wall and diverticular wall (Figure 2B, 3A, 3B, 5A). CT confirmed inflammatory fatty lesion with or without air inside along colonic wall (3, 4), (Figure 4B, 5B, 6C).

Clinical symptoms included acute abdominal pain with rebound tenderness in almost cases. Mild fever, loose stool, only there were some cases with bloody stool. Elevation of the white blood cell count and sedimentary rate.
Eighteen cases were conservatively treated with antibiotic (oral or intravenous) (Figures 6A, 6B). Four cases underwent operation because surgeons suspected acute appendicitis, with post-operative diagnoses 3 cases of diverticulitis of the cecum and 1 case of acute appendicitis.

DISCUSSION

Almost cases in our study with acute colonic uncomplicated diverticulitis on the right-sided colon involving cecum and ascending colon according to Vietnamese who are Oriental (2) and could be patients scared of appendicitis.
Haustra pattern findings of normal colon on ultrasound were useful for exact determination of colon. Thanks to this the diverticulitis was loclated exactly position and corresponding with CT. Specially, diverticulitis of the cecum which had symptoms similar to acute appendicitis. We diagnosed ten cases of cecal diverticulitis in which a case with position of cecum above umbilical level. According to authors, the diagnosis of diverticulitis of the cecum has been the challenge to imaging diagnosis.
Basically, hemicolonic removed for therapy of diverticulitis. However, in our study, eighteen cases were conservatively treated with antibiotic. Four cases were underwent operation because surgeons suspected acute appendicitis, with post-operative diagnoses three cases of diverticulitis of the cecum and a case of acute appendicitis.
To differentiate ACUD from acute appendicitis (in cases of acute appendicitis and wall-off formation surrounded by thick fatty tissue), primary epiploic appendagitis, right-sided segmental infartcion of omentum. The appendicitis is longer than diverticulitis and acute appendicitis has characteristic ultrasound finding so-called finger sign (1) (Figure 7A, 7B). Primary epiploic appendagitis are small, oval, hyperechoic lesion, tenderness and uncompressible, 3-5 cm in size (5) (Figure 7C). Right-sided segmental infarction of omentum are oval, hyperechoic, tenderness, noncompressible with large-size, often bigger 5 cm, which are usually localized at right lower abdomen at the level of umbilicus (6) (Figure 7D).

CONCLUSION

Acute colonic uncomplicated diverticulitis has fairly characteristic sonographic features, therefore US enable diagnosis. Exact determination of colon and cecum thanks to haustra pattern appearances that could to improve the accuracy of diagnosis of colonic diverticulitis. Conservative therapy of ACUD are quite safe no require surgery.

REFERENCES
1. Puylaert JBCM. Acute appendicitis: US evaluation using graded compression. Radiology 158:355, 1986.
2. Khanh t. Nguyen. Bowel and Mesentery, Abdominal Sonography: 253-255.
3. Ruedi F. Thoeni, MD and John P. Cello, MD. CT Imaging of Colitis. Radiology 2006;240:623-638.

COLOR DOPPLER DIAGNOSIS OF ACUTE APPENDICITIS

Tai Van Le, Tai Anh Vo, Hai Thanh Phan, M.D

MEDIC Medical Center, HCM City, Vietnam

I. INTRODUCTION

• Acute appendicitis is a common clinical problem, and one of the most common causes of acute abdominal pain requiring surgical intervention in Vietnam as well as in all other countries of the world. Accurate and prompt diagnosis is essential to minimize morbidity, especially in the case of atypical appendicitis.
• The diagnosis of appendicitis can be based on clinical examination, laboratory findings and medical modalities imaging such as CT scanning and US scanning. In fact, ultrasound, especially color Doppler US combined with graded compression US has proved to be useful and effective in the diagnosis of acute appendicitis by its high specificity (91%), high positive predictive values (95%) and rather high accuracy (83%).

II. MATERIALS AND METHODS

• From 12/2004 to 12/2005, a prospective study was carried out in correlation with surgical intervention results and pathologic findings on 63 patients of age from 2 to 79 (M/F: 32 /31) with clinical symptoms suspected of appendicitis.
• Using graded compression of Puylaert [1]. Appendicitis was firstly detected with B – mode and then hyperemia within the appendiceal wall was assessed on color Doppler. The number of color Doppler signals within the appendiceal wall was classified as absent (0), sparse (1-2), moderate (3-4) or abundant (> 4). The resistive index (RI) was calculated (peak systolic velocity – end diastolic velocity/ peak systolic velocity). In cases of necrotic appendicitis with perforation, hyperemia was sought in the tissues surrouding the appendix including periappendiceal fluid, intestinal wall, greater omentum and psoas muscle. The differences were assessed between abscess, plastron, phlegmon, regional peritonitis, general peritonitis.
• Because of the appendix as known to have variants of position was sought by US planes around the cecum which was firstly localized at its right position depending on the haustrations of the ascending colon with dirty shadowing. The ascending colon was identified by the longitudinal plane from the right hypochondria to the right iliac fossa. And the cecum is terminal haustration of the asceding colon and its variant positions may be below the right lobe of liver, at the umbilical or pelvic level.
• Toshiba Power - Color Doppler US machine with 3.5 – 6 MHz convex and linear probes was used. Low-flow settings (lowest available pulse repetition frequency, highest color Doppler gain possible without background noise signal, low wall filter) were used.

III. RESULTS

• There were 63 cases suspected of appendicitis, 61 cases were true appendicitis (96.8%): 60 cases were operated, 1 case was not operated because it was followed up as a plastron and 2 cases were operated but they were not appendicitis, one case was pyosalpinx, the other was cecal inflammation. There were 42 cases of non-perforated appendicitis (69%); 19 cases of perforated appendicitis (31%). The position of appendix, there were 11 retro-cecal cases (18%) (Fig. 2.g, h, i), 2 pelvic cases (3%), 1 retro-ileal case (1.5%), and 1 umbilicus-directed case (1.5%). The pathologic findings consisted of 5 cases of congestive appendicitis (submucal layer is intact), 54 cases of necrotic appendicitis or purulent appendicitis (submucal layer is necrotic a part or total). Gray- scale US showed 5 cases with intact echogenic submucosal layer, 46 cases non-intact, 8 cases with disappeared echogenic submucosal layer (Table.1).

• There were 42 cases of nonperforated appendicitis, in which 40 cases (95%) with hyperemia: 12 cases of sparse hyperemia (30%) (Fig.2b), 5 cases of moderate hyperemia (13%), 23 cases of abundant hyperemia (57%) (Fig. 2c). There was no hyperemia in 2 cases (5%) (Fig. 2a). The velocity of flow, 7 - 33 cm/sec, was low, (mean 16 cm/s), RI (resistive index) was low: 0.43 - 0.79, (mean 0.6) (Fig.2b).
• There were 19 cases of perforated appendicitis, 2 cases of which the appendixes were not seen because they were completely destroyed (Fig.2d), and 11 cases with hyperemia (58%) consisted of 3 cases with sparse hyperemia (27%), 2 cases with moderate hyperemia (18%), and 6 cases with abundant hyperemia (55%). There were 8 cases without hyperemia (32%) 6 cases of which had no echogenic submucosal layer corresponding to completely destroyed submucosa and 2 cases with incompletely destroyed echogenic submucosal layer (Table.2).
  

• In cases of perforated appendicitis, 9 cases (47%) were abscesses with peripheral hyperemia on color Doppler (100%) (Fig.2d), 2 cases of which had peripheral and central hyperemia. In 5 cases of abscessed appendiceal plastron (phlegmon) (26%), hyperemia existed in the soft tissue around the necrotized appendix including the adjacent bowel wall, the greater omentum and the psoas muscle (Fig.2e) because of important inflammation around the perforated inflamed appendix. There were 2 cases of regional peritonitis (11%) of which only one had hyperemia. There was one case of general peritonitis (5%) without peri-hyperemia. There were 2 cases of plastron (11%) without perihyperemia (Fig.2f) because the inflammation was not severe (Table.3).

Figure 2: US Images for Illustration

IV. DISCUSSIONS

• In almost cases of acute appendicitis, there was hyperemia within the wall of the appendix due to vasodilatation in inflammatory structure accounting for 84% of the cases of non-perforated appendicitis and 58% of those of perforated appendicitis. The velocity of flow was low, RI was low because of high velocity of diastolic flow due to vasodilatation. Congestive appendicitis (with intact of submucal layer) is allways hyperemia; necrotic appendicitis if the submucal is destroyed completely resulting of absent hyperemia, these were corresponding almost blood vessel is distributed within submucal layer. These results are similiar to those in the literature [2]. Therefore Color Doppler aids gray-scale in cases of acute appendicitis at early stage.
• In cases of acute appendicitis with perforation causing abscess, 100% had peripheral hyperemia; this helped us differenciate appendiceal abscess from other types of fluid collection, especially for the cases of necrotic appendicitis in which the appendixes were completely destroyed.
• In addition, hyperemia also helped us differentiate between the plastron (without hyperemia) with phlegmon, regional peritonitis (with hyperemia within tissues around necrotic appendix with perforation). Thanks to this, there were prompt and exact surgical indications. Plastron needed only conservative treatment and delayed surgery, whereas phlegmon and regional peritonitis had to be surgically intervened promptly.
• The method of localization of cecal positions mentioned above proved to be effective and useful in detection of appendix depending on characteristic US haustral pattern of the acending colon. In practice, this helped to improve the accuracy of diagnosis of appendicitis (96.8%).

V. CONCLUSIONS

• Color Doppler shows hyperemia in almost acute appendicitis; spectrum shows low velocity, high diastolic flow, low resistive index (RI). Color Doppler aids gray-scale in cases of acute appendicitis at early stage. Hyperemia in the soft tissue around the perforated appendix often help us to differentiate abscess from plastron, phlegmon, regional and general peritonitis. Peripheral hyperemia in appendiceal abscess has a high specificity (100%).
• Exact determination of position of cecum is very useful in the detection of appendix and therefore helps improve the accuracy of diagnosis of acute appendicitis.
  
  REFERENCES

1. Puylaert JBCM. Acute appendicitis: US evaluation using grade compression. Radiology 1986; 58:355--360.
2. Patriquin HP et al. Appendicitis in children and young aldules: Doppler sonography- phathologic correlation. AJR 1996; 166:629--633.
3. Quiilin SP, Siegel MJ. Diagnosis of appendiceal abscess in children with acute appendicitis: value of color sonography. AJR 1995; 164:1251--1254

Case report: THORACIC KIDNEY

• Thận lạc chỗ hiếm gặp, có những trường hợp rất khó phát hiện, dễ bỏ sót, do lạc chỗ ở những vị trí hiếm gặp (làm cho chúng ta ít nghĩ để tìm), hay ở những vị trí dễ bị che khuất. Chúng tôi xin trình bày trường hợp hiếm nhất trong các trường hợp thận lạc chỗ: Thận lạc chỗ cao (thoracic kidney).
• Bé trai 2 tuổi. Sốt 3 ngày, nhập viện điều trị nhiễm trùng tiểu, 2 ngày sau hết sốt. Siêu âm: 2 lần đầu không thấy thận (T). Sau đó bệnh nhân được làm xạ hình SPECT (Tc-99m) thấy 2 thận bài tiết thuốc bình thường. Siêu âm lần 3: thận trái lạc chỗ cao trên lách dưới cơ hoành (T).

Hình siêu âm cho thấy thận (T) vị trí cao
trên lách ngay dưới cơ hoành (T).




BÀN LUẬN

• Thận hình thành từ nụ niệu quản (ureteric bud), từ tuần thứ 7--9 thai kỳ, đi lên trên. Sự đi lên quá mức: thận ở vị trí cao (thoracic kidney). Sự đi lên bị cản trở kết quả: thận ở vùng chậu, tiểu khung, vị trí thấp. Thận di chuyển ngang sang phía đối bên, thường dính với thận đối bên, hay riêng biệt. Hai thận khác bên kết hợp cho thận hình móng ngựa. Thận lạc chỗ hiếm gặp, thoracic kidney hiếm gặp nhất, ít hơn 5% trong toàn bộ thận lạc chỗ. Sự đi lên quá mức và tuỳ thuộc vào sự hình thành cơ hoành: hoàn chỉnh hay thoát vị hoành: thận đội lên cơ hoành (hình ảnh nhão cơ hoành) hay chui lên lồng ngực khi có thoát vị hoành bẩm sinh. Thoracic kidney gặp bên trái nhiều hơn bên phải, nam nhiều hơn nữ (nam/nữ = 2/1). Không có triệu chứng, chức năng bình thường. Có thể gây giảm sản một phần phổi do bị thận chèn ép.
• XQ tim phổi: có thể có hình ảnh nhão cơ hoành, u trong ngực, u trung thất.
• CT, DSA: giúp chẩn đoán xác định.
• ECHO: chưa tìm thấy đề cặp. Khi siêu âm thấy 1 thận: Thận to bù trừ thường là thận độc nhất, 1 số rất ít thận còn lại thiểu sản hay teo nhỏ. Khi không thấy to bù trừ thì chắc chắn còn 1 thận lạc chỗ ở đâu đó.
• Thoracic kidney rất hiếm gặp, dễ bỏ sót. Tuy nhiên nếu nghĩ tới khi làm siêu âm sẽ phát hiện được và có chẩn đoán chính xác.
  
  REFERENCE
  Yusuf K. Yalcinbas. Thoracic left kidney: a differential diagnostic dilemma for thoracic surgeons. Ann Thorac Surg 2001;72:281-283