Difficult Diagnostic Problems in Pancreatobiliary Neoplasia.

CONTEXT: Many common diagnostic dilemmas are encountered in pancreatobiliary pathology, frequently resulting in uncertainty on behalf of the pathologist and referral for a second opinion. OBJECTIVES: To review 4 common diagnostic dilemmas encountered in the practice of pancreatobiliary pathology: (1) pancreatic ductal adenocarcinoma versus chronic pancreatitis; (2) pancreatic ductal carcinoma versus adenocarcinomas arising in the ampulla and intrapancreatic common bile duct; (3) the distinction of uncommon intraductal neoplasms--intraductal oncocytic papillary neoplasm, intraductal tubulopapillary neoplasm, and intraductal acinar cell carcinoma; and (4) intrahepatic cholangiocarcinoma versus metastatic carcinoma. DATA SOURCES: A review of pertinent literature, along with the authors' personal experience, based on institutional and consultation materials. CONCLUSIONS: Important diagnostic features for a few challenging problems in pancreatobiliary pathology are reviewed. Careful study of the microscopic features along with awareness of differential diagnoses and diagnostic pitfalls generally allows distinction of these entities. We also highlight established and novel ancillary studies that help to arrive at an accurate diagnosis.

Peutz-Jeghers syndrome: a critical look at colonic Peutz-Jeghers polyps.

Peutz-Jeghers syndrome is an autosomal dominant condition characterized by gastrointestinal hamartomatous polyps. The pathologic identification of a Peutz-Jeghers polyp is integral to the diagnosis of this syndrome that often remains undiagnosed until after these polyps are identified. Histologically, Peutz-Jeghers polyps are characterized by a distinctive arborization of smooth muscle within the lamina propria. Colonic Peutz-Jeghers polyps, however, may mimic mucosal prolapse polyps or virtually any colonic polyp that undergoes prolapse. In this paper, we explore the morphological features of colonic Peutz-Jeghers polyps and the diagnostic challenges associated with these polyps. Colonic polyps from patients with Peutz-Jeghers syndrome were identified (n=34). The control cohort, included mucosal prolapse polyps (n=5), hyperplastic polyps (n=10) and tubular adenomas with prolapse (n=9), ganglioneuromatous polyps (n=2) and juvenile polyps (n=14). Intramucosal smooth muscle fibers were identified in all classes of polyps. Twenty-three of the 34 colonic Peutz-Jeghers polyps were characterized by lobulated clusters of colonic crypts. On immunohistochemistry, desmin-positive smooth muscle fibers were seen surrounding these lobules. This lobular organization of the crypts was not identified in mucosal prolapse polyps and hyperplastic polyps or tubular adenomas with prolapse; only one of the 14 juvenile polyps showed this pattern of reactivity on a desmin stain. Our data suggests that the histologic hallmark of colonic Peutz-Jeghers polyps is the lobular organization of the crypts, and that an arborizing pattern of smooth muscle proliferation is neither sensitive nor a specific marker of colonic Peutz-Jeghers polyps. The presence of desmin-positive smooth muscle fibers surrounding the lobules is a helpful diagnostic feature of colonic Peutz-Jeghers polyps, and facilitates the distinction of these polyps from non-Peutz-Jeghers polyps with prolapse-like changes.

Fine needle aspiration diagnosis of carotid body tumor in a case of multiple paragangliomas presenting with facial palsy: a case report.

BACKGROUND: Carotid body tumors (CBTs) constitute the most common extraadrenal paragangliomas. Many lesions diagnosed as CBTs by fine needle aspiration (FNA) cytology are clinically unsuspected. The main differential diagnosis is a thyroid neoplasm. The location of the mass in the lateral neck with prolonged history, hemorrhagic FNA and cytologic features resembling the endocrine neoplasm help in arriving at a suggestive diagnosis of paraganglioma. CASE: A 32-year-old male presented with left-sided facial palsy and swelling in the left side of the neck of 8 months' duration. The FNA sample was hemorrhagic and showed loosely arranged groups and acini formed by round to oval cells. A diagnosis of CBT was suggested. It was supplemented by additional noninvasive methods, such as ultrasonography of the neck region with color Doppler, computed tomography and magnetic resonance imaging of the brain, which also revealed a neoplasm suggestive of carotid body tumor in the right side of the neck and neoplastic lesion in the left cerebellopontine angle, suggestive of paraganglioma. CONCLUSION: FNA, with the other noninvasive radiologic investigations, plays an important role in the diagnosis of CBT. We present this case of multiple paragangliomas for its unusual presentation and FNA diagnosis.