Diagnostic ultrasound ( PDFDrive )

CHAPTER 7 The Pancreas 245
SPL
LK
A
B
FIG. 7.77 Serous Cystic Neoplasm. (A) Transverse sonogram shows lesion through the spleen (SPL) and left kidney (LK). Calciications and
some larger peripheral cysts are noted. (B) Computed tomography image, rotated and cropped to match the ultrasound image, shows the dense
calciications.
TRANS
Debrisfilled
duct
A
B
FIG. 7.78 Intraductal Papillary Mucinous Neoplasm (IPMN). (A) Transverse sonogram shows massively dilated main pancreatic duct (white
and black arrows) illed with mucin, characteristic of main duct IPMN. (B) Another patient in whom a longitudinal oblique sonogram shows IPMN
causing massive bile duct obstruction. Both benign and malignant IPMNs can cause bile duct obstruction. See also Video 7.9.
Intraductal Papillary Mucinous Neoplasm
Intraductal papillary mucinous neoplasm (IPMN) was unreported
before 1982 167 ; other names include intraductal papillary
mucinous tumor, intraductal mucin-hypersecreting neoplasm,
and ductectatic mucinous neoplasm. 154 Unlike mucinous cystic
neoplasm, IMPN arises from the pancreatic ducts, usually in
the head of the pancreas. IMPN occurs in an older population
than mucinous cystic neoplasm and afects men and women
equally.
Mucin is secreted into the ducts, causing prominent dilation
(Fig. 7.78, Video 7.9) and sometimes mucin extrusion from the
ampulla of Vater. 166 IPMN oten presents as acute pancreatitis.
Both benign and malignant lesions can cause bile duct
obstruction 168 (Fig. 7.79). IPMN ranges from a benign to an
overtly malignant lesion. Invasive adenocarcinoma is seen in
approximately 30% of resected cases. Invasive or in situ carcinomas
are likely present in about 70% of patients. 149 he overall 5-year
survival rate for patients with a resected IPMN is higher than
70%. 166 Controversy surrounds the evolving management of these
patients. Some believe that asymptomatic patients or those with
lesions of branch duct origin can be observed or treated with
segmental pancreatectomy. 169
he hallmark of IPMN on ultrasound is ductal dilation (Fig.
7.80; see also Fig. 7.78). Findings include lobulated multicystic
dilation of the branch ducts, difuse dilation of the main pancreatic
duct, and intraductal papillary tumors. 170 Because mucin has a