rsna 2009

GM Werder,1 GA Arnold,1 SA Vartanian,1 F Sokhandon,1 SH Jafri,1 MB Amin,2 IR Francis,3 MA Amendola4

1 Department of Radiology, William Beaumont Hospital, Royal Oak, MI2 Department of Pathology, William Beaumont Hospital, Royal Oak, MI

3 Department of Radiology, University of Michigan, Ann Arbor, MI4 Department of Radiology, University of Miami, Coral Gables, FL

Infectious, Inflammatory, & Neoplastic Conditions of the Retroperitoneum

Objectives

• Describe basic retroperitoneal anatomy

• Present an organized approach to pathologic retroperitoneal processes

• Illustrate patterns of involvement, imaging features, & interpretation pitfalls in an unknown-case format

• Discuss patient management & clinical implications

Retroperitoneum• Boundaries

– Anterior: posterior parietal peritoneum– Posterior midline: anterior longitudinal ligament– Posterior off-midline: paraspinal musculature & transversalis fascia– Lateral: transversalis fascia – Superior: diaphragm– Inferior: pelvis

• Continues inferiorly as pelvic extraperitoneal space

• Contents– Genitourinary: kidneys, ureters, adrenal glands– Gastrointestinal: pancreas*, duodenum*, colon*– Vascular: aorta, inferior vena cava, portal vein– Lymphatic: cisterna chyli, thoracic duct– Neural: celiac plexus, sympathetic trunks– Quadratus lumborum, iliopsoas, & other paraspinal musculature is

technically retrofascial, but practically regarded as retroperitoneal

*pancreatic tail, 1st/4th segments of duodenum, & transverse colon are intraperitoneal

Peritoneum Lateroconal plane

Retromesenteric plane Retrorenal plane

Air in retromesenteric (blue) & retrorenal (yellow) planes in a patient with perforated viscus.

Interfascial Plane Model

A patient with hydronephrosis who underwent bilateral percutaneous nephrostomy complicated by left retroperitoneal hematoma; there is thickening & increased attenuation of the posterior pararenal space (yellow) with extension to the anterior pararenal space (blue), outlining the spared perirenal space (green).

A

Tricompartmental Model Peritoneum Perirenal space

Anterior pararenal space Posterior pararenal space

• Infectious– Nodal

– Vascular

– Musculoskeletal

• Inflammatory– Primary

– Vascular

• Neoplastic– Primary

– Neurovascular

– Metastatic/nodal

Pathologic Processes

Click BLUE subheadings to

navigate to unknown cases

Case 1: 39-year-old male with weight loss & night sweats

A B

(A) Enlarged low-attenuation lymph nodes with peripheral enhancement, characteristic of tuberculous adenitis. (B) Right psoas abscess (cold abscess); though absent here, calcification is not uncommon in tuberculous abscesses.

Sonographic (A, B) and CT (C, D) correlation of bulky hypoechoic, low-attenuation lymphadenopathy. CT-guided biopsy (E) was positive for Mycobacterium tuberculosis.

A

C

B

D

E

Case 1: Companion case

Case 2: Immunocompromised adult female with fever

A patient with Mycobacterium avium-intracellulare lymphadenopathy. As compared to tuberculous lymphadenopathy, these nodes are smaller, more

numerous, more discrete, & exhibit uniform soft tissue attenuation.

Another patient with Mycobacterium avium-intracellulare lymphadenoapathy. Axial CT (A) shows bulky retroperitoneal lymph nodes without vascular or intestinal displacement. Again, relative to tuberculous adenopathy, these nodes are smaller, more numerous, more discrete, & of uniform

soft tissue attenuation. Pathology (B) shows innumerable intracellular acid-fast bacilli.

A B


Case 2: Companion case #2

Although central low attenuation with peripheral enhancement is more typical of tuberculous lymphadenopathy, culture in this patient yielded Mycobacterium avium-intracellulare, illustrating the overlap in imaging appearance.

Initial CT (A) demonstrates partially calcified retroperitoneal lymph nodes. Six month follow-up CT (B) demonstrates new lytic osseous lesion & bilateral psoas abscesses, of which the

left is contiguous with the spine lesion.

A B

Case 3: 30-year-old male with AIDS, fever, chills, & abdominal pain

CT-guided biopsy (A) of a calcified left para-aortic lymph node; hematoxylin & eosin (B) shows necrotizing granulomatous inflammation & Grocott stain (C)

shows numerous fungal yeast forms, compatible with Histoplasma capsulatum.

Case 3: 30-year-old male with AIDS, fever, chills, & abdominal pain

BA C

Another patient with AIDS & similar-appearing partially calcified retroperitoneal lymphadenopathy. Methenamine silver stain of a biopsied lymph node was consistent

with extrapulmonary Pneumocystis jirovecii (formerly Pneumocystis carinii).

Case 4: Adult female with AIDS, cough, fever, chills, weight loss, & abdominal pain

• Mycobacterium tuberculosis– Lymphadenopathy most common abdominal manifestation of TB– Central low attenuation (caseation necrosis), peripheral enhancement

(inflammatory granulomatous hypervascularity), may calcify – Similar to MAC, metastases, Whipple disease, & lymphoma

• Mycobacterium avium-intracellulare (MAC)– Common in AIDS and may mimic Kaposi sarcoma or lymphoma– Tend to be smaller & uniform soft tissue attenuation compared to TB

• Histoplasmosis capsulatum– Enlarged, variable appearance: homogeneous soft-tissue density (44%),

diffuse or central low density (13%), or both (19%)– May calcify

• Pneumocystis jirovecii (formerly Pneumocystis carinii)– Extrapulmonary disease occurs in 1% & is associated with use of

aerosolized pentamidine, which suppresses pulmonary infection but has no extrapulmonary effect

– Imaging features not well documented

Infectious Lymphadenopathy


• Mycobacteria, Histoplasma, Pneumocystis– Vascular

– Musculoskeletal


– Vascular


– Neurovascular



Click RED subheadings to . navigate to previous cases .

Click BLUE subheadings to navigate to unknown cases

Case 5: Adult female with signs of sepsis, but negative blood cultures & no identifiable source of infection

A B

Presentation CT (A) demonstrates periaortic soft tissue, which was interpreted as reactive lymphadenopathy secondary to occult infection; patient was discharged on

antibiotics. Follow-up CT (B) obtained 3 weeks later for recurrent sepsis demonstrates increased inflammation & left posterolateral outpouching consistent with mycotic

aneurysm. Repeat blood cultures were positive for Salmonella enteriditis.

Short-term follow up demonstrates development of eccentric saccular

mycotic aneurysm.

Hepatic flexure wall thickening & adjacent inflammation, periaortic

inflammatory change, & gas within wall of abdominal aorta, compatible with infectious aortitis secondary to

perforated colon cancer.

One-month follow-up demonstrates interval increase in size.

Postoperative changes of axillobifemoral bypass with aortic

ligation, excision of the aneurysm, & devascularization of the left kidney.


Axial (A) & coronal (B) CT demonstrate abdominal aortic aneurysm with surrounding inflammatory change interpreted as rupture. Patient consequently underwent urgent endovascular stent-graft repair (C).

Follow-up CT 3 weeks later (D) demonstrates progression of saccular dilatation & inflammatory change compatible with mycotic aneurysm & stent-graft infection.

A B

D

C

Case 6: Adult male with abdominal pain

A

B

DC


(A) Large mycotic aneurysm on digital subtraction angiography shows mural thickening/soft tissue mass on CT (B) with erosion into adjacent spine causing discitis/osteomyelitis, evident on pre- (C) & post-contrast (D) lumbar MRI.

Mycotic Aortic Aneurysm• Pathogenesis

– Inoculation• Septic embolization of vasa vasorum (e.g. endocarditis)• Hematogenous seeding of preexisting intimal defect (e.g. sepsis)• Contiguous involvement from adjacent source (e.g. Crohn’s, discitis)• Direct traumatic inoculation (e.g. stab wound, intravenous drug use)

– Negative blood cultures in 25%• When positive, most commonly Salmonella, Staphylococcus, & Streptococcus

– Acute rupture/hemorrhage in 75%– Mortality rate 67%

• Imaging features– Lobulated, eccentric, saccular aneurysm with indistinct, irregular wall– Rarely calcified (exception: syphilitic aneurysm)– Perianeurysmal edema, gas, soft tissue mass, &/or enhancement– Increased accumulation of 111Indium-labeled white blood cells

• Risk factors & demographics– IV drug use, immunodeficiency, bacterial endocarditis, vascular prostheses– Incidence: 1-2.5% of all aortic aneurysms

• Management:– Endovascular (stent-graft) or surgical (bypass) intervention– Prolonged antibiotic therapy



• Mycotic aneurysm– Musculoskeletal


– Vascular


– Neurovascular





Case 7: Adult male with lower back pain & radiculopathy

Axial CT demonstrates marked vertebral body

destruction with contiguous bilateral psoas abscesses.

Sagittal gadolinium-enhanced MRI demonstrates vertebral body destruction

out of proportion to intervertebral disc space involvement, compatible with

tuberculous spondylitis.

Case 7: Adult male with lower back pain & radiculopathy

T1 PostcontrastT1 Postcontrast

In contrast to disc sparing as in TB infection, patchy disc enhancement in this patient is characteristic of pyogenic spondylodiscitis. Also noted is dural thickening & enhancement, as well as extension of disease into the psoas muscles. Culture was positive for Streptococcus viridans.

T1 Precontrast T1 Postcontrast

T1 Precontrast

T1 Postcontrast

Postcontrast CT

Case 8: Adult male with severe lumbar back pain

T1 Precontrast T1 PostcontrastFeatures which help distinguish tuberculous spondylitis from pyogenic spondylodiscitis:

• 3 or more contiguous segments involved

• Multiple noncontiguous “skip” lesions (yellow)

• Anterior vertebral body collapse with resultant focal kyphosis (Gibbous deformity; green)

• Disproportionate prevertebral soft tissue extending craniocaudally along anterior longitudinal ligament (blue)

• Relative intervertebral disc sparing (red)

Axial imaging of the prior patient demonstrates paraspinal cold abscesses under the anterior longitudinal ligament. CT images better depict vertebral

body destruction. Biopsy revealed necrotizing granulomatous inflammation & sequestrum, typical of tuberculous spondylitis (Pott’s disease).

T1 Precontrast T1 Postcontrast T2

Precontrast CT Postcontrast CT CT-Guided Biopsy

Oblique pelvic radiographs (A, B) reveal ill-defined margins of right sacroiliac joint (blue). Pre- (C) & post-contrast (D) T1WI demonstrates enhancement of right sacroiliac joint with extension

to right iliopsoas muscle. Blood culture positive for Enterobacter & clinical/imaging improvement on ertapenem helped confirm diagnosis of pyogenic sacroiliitis.

A

B D

C

Case 9: Adolescent male with right hip pain

Axial CT demonstrates a fluid-attenuation collection in the left psoas muscle with a thick enhancing wall, compatible with psoas abscess. Aspirate revealed Staphylococcus aureus.

Case 10: 71-year-old female on ribavirin for hepatitis C with fever, chills, & left lower abdominal quadrant pain

Case 11: Adult male with right lower abdominal quadrant pain, fever, & leukocytosis

BA

Axial CT demonstrates ruptured appendicitis with retroperitoneal air extending superiorly into right posterior

pararenal space (blue) & along lateral conal plane (red), as well as inferiorly along iliopsoas muscle into proximal thigh.

Case 11: Adult male with right lower abdominal quadrant pain, fever, & leukocytosis

Percutaneous drainage was performed (A) with complete resolution several days later (B).

BA

Musculoskeletal Infections with Retroperitoneal Extension

• Tuberculous spondylitis (Pott’s disease)– Incidence increasing secondary to immigration & AIDS– Epicenter typically anteroinferior vertebral body, with disease extension

along ligaments, sparing intervertebral discs– Contiguous vertebral segment involvement, skip lesions, & paraspinal

abscesses are characteristic

• Pyogenic spondylodiscitis– Most common causative organism Staphylococcus aureus (60%),

Enterobacter (30%), Escherichia coli, Pseudomonas, and Klebsiella• Remains true in immunocompromised populations

– Inoculation via hematogenous spread (e.g. intravenous drug use), ascending route (e.g. genitourinary manipulation), direct (e.g. postsurgical)

– In adults, epicenter is vertebral body endplate; in children, begins in disc

• Pyogenic sacroiliitis– Extremely rare & predominately affects pediatric & young adult patients– Most common organisms Staphylococcus, Streptococcus, & Salmonella




• Pott's disease, discitis/osteomyelitis, sacroiliitis, psoas abscess


– Vascular


– Neurovascular





Case 12: 44-year-old male with elevated angiotensin converting enzyme level

BA

(A) CT scout image shows coarse linear pulmonary parenchymal opacities & upper lung predominant peribronchovascular nodules. (B) Axial CT shows extensive retroperitoneal lymphadenopathy, biopsy of which demonstrated

non-caseating granulomatous tissue compatible with sarcoidosis.


(A) Axial CT through the lungs demonstrates bilateral hilar lymphadenopathy & interstitial disease. (B) Axial CT through the upper abdomen shows retrocrural & aortocaval lymphadenopathy (blue), compatible with retroperitoneal sarcoidosis.

BA

Case 13: 75-year-old male with flank pain

Axial CT demonstrates extensive soft tissue encasing the aorta from above the celiac axis to below the iliac bifurcation; ureteral involvement is resulting in hydroureteronephrosis, likely responsible for the patient’s symptoms.

Case 13: 75-year-old male with flank pain

Percutaneous biopsy performed to exclude lymphoma & metastatic adenopathy confirmed suspected diagnosis of retroperitoneal fibrosis.

Case 14: 50-year-old male with intermittent bilateral flank pain for 3 days

D

Axial & coronal CT demonstrates bilateral hydronephrosis & inflammatory soft tissue extending along the course of the left ureter (blue).

Case 14: 50-year-old male with intermittent bilateral flank pain for 3 days

Biopsy demonstrated “foamy histiocytes,” lipid-laden macrophages characteristic of Erdheim-Chester disease.

Extensive symmetric periureteral mixed attenuation tissue exhibiting both soft tissue & macroscopic fat components with resultant right-sided hydronephrosis.



Coronal reformatted images demonstrating the same findings.


BA C

D

(A, B) CT of the orbits shows a similar fibroproliferative process in the retrobulbar region as that seen in the retroperitoneum.

(C) Bone scintigraphy demonstrates right-sided hydronephrosis & bilateral increased tibial diaphyseal accumulation of radiotracer.

(D) Presumptive diagnosis of Erdheim-Chester disease was made & percutaneous retroperitoneal biopsy was performed; however,

pathology demonstrated fibroadipose tissue with lymphocytic infiltration rather than the lipid-laden macrophages characteristic of Erdheim-Chester, consistent with a diagnosis of fibrolipomatosis.

• Retroperitoneal sarcoidosis– Etiology: unknown– Imaging

• Chest findings present in 90% of patients with sarcoidosis• Retroperitoneal lymph node involvement rare (usually associated chest findings)• Retroperitoneal lymphadenopathy in patient with sarcoidosis remains non-specific

& must be differentiated from lymphoma or metastatic disease– Treatment: corticosteroids

• Idiopathic retroperitoneal fibrosis– Etiology: autoimmune, drug reaction (methysergide, β-blockers, hydralazine) – Imaging: vascular encasement; medial ureteral deviation/hydronephrosis– Treatment: corticosteroids

• Erdheim-Chester (“polyostotic sclerosing” or “non-LCH” histiocytosis)– Etiology: abnormal proliferation of tissue macrophages (histiocytes)– Manifestations

• Bone pain (secondary to diaphyseal sclerosis)• Urinary symptoms (secondary to retroperitoneal fibrosis)• Diabetes insipidus (secondary to pituitary involvement)• Exophthalmos (secondary to retrobulbar fibrosis)

– Treatment: corticosteroids

D

Primary Inflammatory Conditions

CT at presentation (A) demonstrates multiple low-attenuation collections within the right kidney oriented peripherally around a large central “staghorn” calculus, imaging features typical of

xanthogranulomatous pyelonephritis. Ten month follow-up CT (B) shows interval development of marked perirenal fibrofatty proliferation with neoplasm-like extension into the posterolateral

abdominal wall, compatible with retroperitoneal xanthogranulomatosis.

Case 15: Adult female with nausea & lethargy

At presentation 10 months later

A B


At presentation 10 months later

Two additional patients with retroperitoneal xanthogranulomatosis demonstrating characteristic extensive fibrofatty proliferation

• Pathogenesis– Rare inflammatory response to chronic renal infection characterized by

destruction & replacement of renal parenchyma with lipid-laden "foamy" macrophages (xanthoma cells) & granulomatous infiltrate

– Chronic renal infection generally secondary to obstructive process

• Classic triad of imaging findings– Diffuse renal enlargement with multiple focal low-attenuation xanthomatous

collections replacing renal parenchyma in a hydronephrotic-like distribution• Differentiate from hydronephrosis by lack of infundibular/pelvic dilatation

– Obstructing staghorn calculus (70%)– Perirenal fibrofatty proliferation

• Risk factors & demographics– 45-65 years– Female predominance– Diabetes mellitus in immunocompromised patients– Abnormal lipid metabolism

• Management: nephrectomy– Careful assessment of contralateral kidney critical

Retroperitoneal Xanthogranulomatosis






• Sarcoidosis, idiopathic fibrosis, Erdheim-Chester, xanthogranulomatosis– Vascular


– Neurovascular





Case 16: 57-year-old female with polymyalgia rheumatica, night sweats, anemia, & elevated CRP/ESR*

A B

C

At presentation 3 years prior

Follow-up

*CRP: C-reactive protein; ESR: Erythrocyte sedimentation rate

Axial CT (A) demonstrates aortic mural thickening & enhancement (blue), not present

on examination three years prior (B), consistent with non-infectious aortitis; short-

term follow-up MRI (C) confirms findings.

Case 17: 73-year-old male with prior abdominal aortic aneurysm repair presents with gastrointestinal bleeding

Axial CT shows abnormal communication (blue) between the aorta & jejunum, consistent with aortoenteric fistula. The patient was not a surgical candidate & expired with conservative therapy.


Axial CT demonstrates a large aortic aneurysm with internal curvilinear hyperdensity & extensive retroperitoneal hemorrhage into the left anterior & posterior pararenal spaces,

compatible with aneurysmal rupture. The patient underwent emergent aortobifemoral bypass, but suffered a myocardial infarction in the perioperative period & subsequently

developed both renal & respiratory failure. Care was withdrawn one week later.


Axial CT demonstrates active extravasation of contrast from a ruptured infrarenal abdominal aortic aneurysm; the patient underwent

emergent aortoiliac stent graft placement & made a full recovery.

Case 18: 86-year-old anticoagulated male with back pain, shortness of breath, & supratherapeutic INR

Axial CT demonstrates blood in the right posterior pararenal space infiltrating/expanding the right iliopsoas muscle & resulting in

surrounding fat stranding, compatible with retroperitoneal hematoma.


Axial pre- (A) & post-contrast (B) CT in another patient with retroperitoneal hematoma demonstrates a less typical appearance.

A B


Coronal (A) & axial (B) CT in a trauma patient demonstrate a mass-like retroperitoneal

hematoma (blue) inferoposterior to the duodenum.A

B

Pathologic Processes• Infectious

– Nodal• Mycobacteria, Histoplasma, Pneumocystis

– Vascular• Mycotic aneurysm

– Musculoskeletal• Pott's disease, discitis/osteomyelitis, sacroiliitis, psoas abscess



• Aortitis, ruptured aortic aneurysm, retroperitoneal hematoma


– Neurovascular




Case 19: 50-year-old female with left lower abdominal quadrant pain

CT shows a large encapsulated left retroperitoneal mass adjacent to the anterior aspect of the left kidney. Upon en bloc resection of the mass & left kidney, pathology was

consistent with a leiomyoma of renal capsular smooth muscle cell origin.

Case 20: 53-year-old female with palpable mass

Multiplanar reconstructed CT shows a large, heterogeneously enhancing retroperitoneal mass arising from the anterior aspect of the left kidney; ultrasound-guided biopsy was

positive for leiomyosarcoma.

Case 21: 57-year-old male with abdominal distension

Axial CT demonstrates a large heterogeneous retroperitoneal mass composed of adipose & soft tissue markedly displacing

all intrabdominal contents.

Upon resection of a 40 lb mass, pathology was positive for a

mixed low-grade liposarcoma with lipomatous, sclerosing, &

myxoid subtypes.

Axial CT demonstrates a large heterogeneous retroperitoneal

mass with scant areas of internal macroscopic fat.

Pathology was positive for a well-differentiated sclerosing

subtype liposarcoma.


Axial CT demonstrates a large heterogeneous retroperitoneal

mass with scant areas of internal macroscopic fat.

Pathology was positive for a well-differentiated sclerosing

subtype liposarcoma.


Axial CT demonstrates a large heterogeneous retroperitoneal mass composed of adipose & soft tissue.

Pathology was positive for a high-grade dedifferentiated liposarcoma.


Axial CT shows a large primarily soft

tissue density retroperitoneal

mass displacing the right kidney & all intrabdominal

contents to the left abdomen.

Pathology was consistent with a myxoid subtype

liposarcoma.

Case 22: 63-year-old male with abdominal discomfort

Axial CT demonstrates a large heterogeneously enhancing right retroperitoneal mass closely

approximated to the inferior pole of the right kidney.

Percutaneous biopsy yielded tissue compatible with primary retroperitoneal malignant fibrous histiocytoma.

Case 23: 79-year-old female with abdominal pain & shortness of breath

Axial CT demonstrates contained rupture of an aortic pseudoaneurysm

within extensive periaortic soft tissue (blue). The

patient expired & autopsy showed malignant fibrous histiocytoma encasing & invading the suprarenal aorta, celiac artery, left renal artery, & adrenal

artery, as well as involving the pancreatic head, left kidney, & left

adrenal gland.

Case 24: 3-year-old female with palpable mass

Axial CT shows a large left upper

abdominal quadrant mass with internal

fat, fluid, soft tissue, & calcium density, compatible with teratoma; upon

surgical resection, the location of the

mass was confirmed to be retroperitoneal.









• Leiomyoma/-sarcoma, liposarcoma, malignant fibrous histiocytoma, teratoma– Neurovascular





Case 25: 43-year-old male with longstanding history of neurofibromatosis

Axial CT (A) demonstrates a large heterogeneous left-sided retroperitoneal mass. Bone window (B) shows expansion of sacral neural foramina (blue). CT-guided biopsy (C)

was compatible with neurofibrosarcoma.

A

B C

CT T1 C–

T1 C+

T2

T1 C–

CT T1 C–

T1 C+

T2

T1 C–


A

B C

Axial CT & contrast-enhanced MRI show two round low-attenuation, low-T1/high-T2, enhancing lesions (blue) arising from the L4 & L5 nerve roots, compatible with peripheral nerve sheath tumors.

Precontrast

Postcontrast (90 sec)

Postcontrast (3 min)

Case 26: 74-year-old male with hypertension

Axial & coronal CT demonstrate a large

heterogeneously enhancing left

retroperitoneal mass that is distinct from normal adrenal glands (blue).

Percutaneous biopsy was performed &

pathology was positive for extra-adrenal

pheochromocytoma.


Axial & coronal CT images show a large

heterogeneously enhancing right

retroperitoneal mass with cystic areas & calcification that is

distinct from normal adrenal glands (blue).

Biopsy was positive for extra-adrenal

pheochromocytoma.

This particular mass falls in the minority of pheochromocytomas that are calcified, as

well as in the minority that are extra-adrenal.

Case 27: 41-year-old female with right flank pain

Axial CT demonstrates

Biopsy proven leiomyosarcoma of

vascular origin.

Axial CT & contrast-enhanced MRI show a combination of tumor thrombus (blue) & bland thrombus (red) involving the IVC & right renal vein. The patient

underwent transjugular biopsy, which was positive for IVC leiomyosarcoma.

CT

T2 LAVA early LAVA late

T1 precontrast T1 postcontrast










• Peripheral nerve sheath tumor, pheochromocytoma, IVC leiomyosarcoma– Metastatic/nodal




Case 28: 72-year-old female with new neck nodule

Axial CT shows bulky retroperitoneal lymphadenopathy (blue) that encases, but does not compress, mesenteric vasculature; this is a characteristic finding of lymphoma.

Case 28: 72-year-old female with new neck nodule

Axial CT demonstrates an infiltrating process involving the perirenal spaces

bilaterally, resembling inflammatory stranding; however, as there is no

hydronephrosis, biopsy was performed, which was positive for non-

Hodgkin’s lymphoma.

Case 29: 51-year-old female with flank pain & hematuria

Axial CT shows left renal enlargement with a mixed attenuation subcapsular collection & perinephric

fascial thickening & inflammatory stranding.

Initially thought to represent hemorrhagic

renal cell carcinoma, the left kidney & adrenal

gland were resected en bloc & pathology was

consistent with metastatic rhabdoid tumor with renal capsular, perinephric, &

lymphovascular invasion. Images also demonstrate periarterial involvement with a large renal infarct

and tumor thrombus within the renal vein.

Case 30: 35-year-old male status post orchiectomy for non-seminoma germ cell tumor, routine tumor surveillance

2005 2006

2007 2008

Serial axial CT images demonstrate a slow-growing, homogenous, low-attenuation mass in the aortocaval space at the level of the aortic bifurcation.

Case 30: 35-year-old male status post orchiectomy for non-seminoma germ cell tumor, routine tumor surveillance

CT-guided biopsy of the mass demonstrates a keratinaceous cyst, a mature teratomatous element from the patient’s known testicular tumor, compatible with growing teratoma syndrome.

• Diagnosis– Slow-growing mass post-chemotherapy for non-seminoma germ cell tumor– Typically occurs in mediastinum or retroperitoneum– Absence of tumor marker elevation (AFP, β-hCG, LDH), even in patients

who exhibit marked elevation from primary tumor– Pathology:

• Presence of benign mature teratomatous elements• Absence of immature malignant germ cells

• Pathogenesis (proposed theories)– Chemotherapy selectively kills immature malignant cells, leaving only mature

benign teratomatous elements– Chemotherapy-induced or spontaneous transformation of an immature

malignant germ cell into a benign mature teratomatous element

• Complications– Mass effect on adjacent structures– Malignant degeneration

• Management: complete surgical resection

Growing Teratoma Syndrome










• Peripheral nerve sheath tumor, pheochromocytoma, IVC leiomyosarcoma– Metastatic/nodal

• Lymphoma, metastasis, growing teratoma syndrome

Summary

THANK YOU!

rsna 2009

Documents

companion case case

b axial ct

lowattenuation lymph

pathology b

retroperitoneal hematoma

initial ct

anterior pararenal space

month followup ct b