Diagnostic Ultrasound - Abdomen and Pelvis
Solid Peritoneal Mass Mimics Benign Mesenchymal Tumor (Left) Transverse color Doppler ultrasound of the pelvis shows an ovoid, hypoechoic lesion with central echogenic fat ſt representing a mature teratoma. No color flow is seen in the fatty component, which exhibits shadowing st. (Right) Transverse ultrasound of the right lower quadrant in a patient status posthysterectomy shows a hypoechoic solid mass st with posterior acoustic shadowing ſt and no color flow. This was a leiomyoma at surgical excision. Biopsy was not possible due to firmness. Differential Diagnoses: Abdominal Wall/Peritoneal Cavity Peritoneal Sarcomatosis Peritoneal Lymphomatosis (Left) Transverse ultrasound of the left upper abdomen in a patient with Burkitt lymphoma shows a large, heterogeneous, predominantly solid mass ſt. There was ascites inferiorly. (Right) Axial NECT of the same patient shows the mixed density lymphomatous mass ſt as well as lymphomatous deposits in the right abdomen st. There was ascites on other images. Peritoneal Tuberculosis Papillary Serous Carcinoma (Left) Transverse transabdominal ultrasound in a patient with peritoneal tuberculosis shows omental thickening ſt superficial to matted bowel . There is a small amount of ascites . (Right) Coronal transvaginal color Doppler ultrasound of the left adnexa shows ascites ſt, thick malignant peritoneum with color flow , and a solid peritoneal mass . This was primary peritoneal serous carcinoma. 985
Cystic Peritoneal Mass Differential Diagnoses: Abdominal Wall/Peritoneal Cavity DIFFERENTIAL DIAGNOSIS Common • Abscess • Organizing Hematoma • Complicated Ascites • Pancreatic Pseudocyst • Cystic Ovarian Masses Less Common • Paraovarian/Paratubal Cyst • Localized Collections ○ Biloma, Urinoma, CSF Pseudocyst • Pedunculated Cyst/Diverticula • Peritoneal Inclusion Cyst • Cystic Non Ovarian Malignant Neoplasm ○ Cystic Metastasis ○ Pseudomyxoma Peritonei ○ Pedunculated Cystic Tumor – Gastrointestinal Stromal Tumor (GIST) – Cystic Leiomyosarcoma – Pancreatic Mucinous Cystadenoma/Cystadenocarcinoma ○ Cystic Mesenchymal Tumor – Malignant Fibrous Histiocytoma – Synovial Sarcoma • Cystic Benign Neoplasm ○ Mesenteric Teratoma ○ Multicystic Mesothelioma • Cystic Lymph Nodes Rare but Important • Mesenteric/Omental Cyst ○ Lymphangioma ○ Nonpancreatic Pseudocyst ○ Enteric Duplication Cyst ○ Enteric Cyst ○ Mesothelial Cyst • Urachal Cyst/Abscess • Infarcted Accessory Spleen ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Lesions with relevant history ○ Abscess, organizing hematoma • Lesions with characteristic appearances ○ Peritoneal inclusion cyst, pseudomyxoma peritonei, mature teratoma (dermoid), enteric duplication cyst • Lesions with thin-walled cystic appearance unless complicated ○ Mesenteric/omental cysts ○ Pedunculated cyst from adjacent organs • Lesions with complicated appearance ○ Any cystic neoplasm mentioned above or cystic lesion with complication (infection/hemorrhage) ○ Bowel wall origin suggests GIST ○ Other lesions nonspecific, need clinical information to make specific diagnosis and biopsy/aspiration to confirm Helpful Clues for Common Diagnoses • Abscess ○ Pyogenic – Unilocular/multiloculated; thin-/thick-walled plus debris-fluid level – Echogenic foci with "ring-down" artifacts/"dirty" shadow = gas □ Consider infection with gas forming organism or bowel leak – Occasionally, surgical hemostatic agents (cellulose) will mimic gas-containing collection, surgical history is key ○ Tuberculous – With features of TB peritonitis or GI/renal/mesenteric lymph node involvement ○ Parasitic – Hydatid disease: 12% affects peritoneum – Variable appearance ranging from heterogeneous solid-looking mass to complex cystic mass • Organizing Hematoma ○ History of trauma, coagulopathy, or anticoagulant therapy ○ Organization with liquefaction in subacute to chronic stage ○ Localized collection with multiple thick septa horizontally aligned ± layering debris ○ May be difficult to determine origin with ultrasound • Complicated Ascites ○ Infection, hemorrhage, inflammation ○ Septations and loculation develop over time – Multiple, thick, irregular septa in chronic cases • Cystic Ovarian Masses ○ Benign and malignant cystic neoplasms ○ Mucinous and serous cystadenoma and cystadenocarcinoma ○ Mature cystic teratoma ○ Variable appearances depending on pathology Helpful Clues for Less Common Diagnoses • Paraovarian/Paratubal Cyst ○ Typically small and simple, separate from ovary • Localized Collections ○ Urinomas, lymphoceles, bilomas ○ CSF pseudocyst associated with ventriculoperitoneal shunt, due to inflammation or infection – Cysts are close to shunt tip and contain tubing • Pedunculated Cyst/Diverticula ○ Hepatic, splenic, renal cyst, or GI diverticula ○ Origin may be difficult to trace ○ May cause abdominal pain and palpable mass if hemorrhagic or infected • Peritoneal Inclusion Cyst ○ Fluid conforming to peritoneal cavity with internal septa producing multilocular lesion ○ Low-resistance flow sometimes present in septa from vessels in mesothelial lining ○ May appear complicated if containing debris/hemorrhage ○ Loculated fluid may surround normal ipsilateral ovary and produce characteristic "spider in web" appearance 986
- Page 956 and 957: Focal Splenic Lesion Pyogenic Absce
- Page 958 and 959: Focal Splenic Lesion Splenic Infarc
- Page 960 and 961: PART III SECTION 5 Urinary Tract 9
- Page 962 and 963: Intraluminal Bladder Mass Bladder C
- Page 964 and 965: Abnormal Bladder Wall □ Uterine c
- Page 966 and 967: Abnormal Bladder Wall Invasion by P
- Page 968 and 969: PART III SECTION 6 Kidney Enlarged
- Page 970 and 971: Enlarged Kidney - Nonneoplastic cau
- Page 972 and 973: Enlarged Kidney Perinephric Fluid C
- Page 974 and 975: Small Kidney ○ Pseudotumors from
- Page 976 and 977: Small Kidney Postobstructive Atroph
- Page 978 and 979: Hypoechoic Kidney • Multiple Myel
- Page 980 and 981: Hypoechoic Kidney Acute Renal Arter
- Page 982 and 983: Hyperechoic Kidney ○ Echogenic co
- Page 984 and 985: Hyperechoic Kidney Chronic Glomerul
- Page 986 and 987: Cystic Renal Mass ○ Associated wi
- Page 988 and 989: Cystic Renal Mass Multicystic Dyspl
- Page 990 and 991: Solid Renal Mass • Horseshoe Kidn
- Page 992 and 993: Solid Renal Mass Renal Lymphoma Ren
- Page 994 and 995: Renal Pseudotumor Column of Bertin
- Page 996 and 997: Dilated Renal Pelvis • Intrarenal
- Page 998 and 999: Dilated Renal Pelvis Pyonephrosis P
- Page 1000 and 1001: PART III SECTION 7 Abdominal Wall/P
- Page 1002 and 1003: Diffuse Peritoneal Fluid Hemoperito
- Page 1004 and 1005: Solid Peritoneal Mass - Higher dens
- Page 1008 and 1009: Cystic Peritoneal Mass ○ Women of
- Page 1010 and 1011: Cystic Peritoneal Mass Pseudomyxoma
- Page 1012 and 1013: PART III SECTION 8 Prostate Enlarge
- Page 1014 and 1015: Enlarged Prostate Benign Prostatic
- Page 1016 and 1017: Focal Lesion in Prostate ○ Variab
- Page 1018 and 1019: Focal Lesion in Prostate Müllerian
- Page 1020 and 1021: PART III SECTION 9 Bowel Bowel Wall
- Page 1022 and 1023: Bowel Wall Thickening - Distal ileu
- Page 1024 and 1025: Bowel Wall Thickening Crohn Disease
- Page 1026 and 1027: Bowel Wall Thickening Clostridium D
- Page 1028 and 1029: PART III SECTION 10 Scrotum 1008
- Page 1030 and 1031: Diffuse Testicular Enlargement Test
- Page 1032 and 1033: Decreased Testicular Size Testicula
- Page 1034 and 1035: Testicular Calcifications Sertoli C
- Page 1036 and 1037: Focal Testicular Mass - Most common
- Page 1038 and 1039: Focal Testicular Mass Testicular Ly
- Page 1040 and 1041: Focal Extratesticular Mass - 3-50 m
- Page 1042 and 1043: Focal Extratesticular Mass Inguinal
- Page 1044 and 1045: Focal Extratesticular Mass Liposarc
- Page 1046 and 1047: Extratesticular Cystic Mass Varicoc
- Page 1048 and 1049: PART III SECTION 11 Female Pelvis
- Page 1050 and 1051: Cystic Adnexal Mass □ Hemorrhagic
- Page 1052 and 1053: Cystic Adnexal Mass Dermoid (Mature
- Page 1054 and 1055: Solid Adnexal Mass - May masquerade
Solid Peritoneal Mass<br />
Mimics<br />
Benign Mesenchymal Tumor<br />
(Left) Transverse color<br />
Doppler ultrasound of the<br />
pelvis shows an ovoid,<br />
hypoechoic lesion with central<br />
echogenic fat ſt representing<br />
a mature teratoma. No color<br />
flow is seen in the fatty<br />
component, which exhibits<br />
shadowing st. (Right)<br />
Transverse ultrasound of the<br />
right lower quadrant in a<br />
patient status posthysterectomy<br />
shows a<br />
hypoechoic solid mass st with<br />
posterior acoustic shadowing<br />
ſt <strong>and</strong> no color flow. This was<br />
a leiomyoma at surgical<br />
excision. Biopsy was not<br />
possible due to firmness.<br />
Differential Diagnoses:<br />
Abdominal Wall/Peritoneal Cavity<br />
Peritoneal Sarcomatosis<br />
Peritoneal Lymphomatosis<br />
(Left) Transverse ultrasound of<br />
the left upper abdomen in a<br />
patient with Burkitt<br />
lymphoma shows a large,<br />
heterogeneous, predominantly<br />
solid mass ſt. There was<br />
ascites inferiorly. (Right) Axial<br />
NECT of the same patient<br />
shows the mixed density<br />
lymphomatous mass ſt as<br />
well as lymphomatous<br />
deposits in the right abdomen<br />
st. There was ascites on other<br />
images.<br />
Peritoneal Tuberculosis<br />
Papillary Serous Carcinoma<br />
(Left) Transverse<br />
transabdominal ultrasound in<br />
a patient with peritoneal<br />
tuberculosis shows omental<br />
thickening ſt superficial to<br />
matted bowel . There is a<br />
small amount of ascites .<br />
(Right) Coronal transvaginal<br />
color Doppler ultrasound of<br />
the left adnexa shows ascites<br />
ſt, thick malignant<br />
peritoneum with color flow<br />
, <strong>and</strong> a solid peritoneal<br />
mass . This was primary<br />
peritoneal serous carcinoma.<br />
985
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