Differential diagnosis

Abstract

The differential diagnosis of hilar cholangiocarcinoma (HCCA) that include primary malignancies, metastatic disease and benign lesions is challenging and presents a diagnostic dilemma in surgery. Generally, biliary tumors are accompanied by painless jaundice with evidence of biliary obstruction [1, 2]. Currently, this presentation by itself is usually enough to raise a strong suspicion of neoplastic biliary obstruction. The clinical findings and laboratory values including tumor markers are non-specific and cannot correctly identify the exact cause of the stricture. Thus, preoperative differential diagnosis, which is desirable to confirm surgical indication and to advise patients about the disease and their respective prognosis, is extremely difficult. Although the assessment of patients with obstructive jaundice has greatly improved by the currently available noninvasive, and invasive imaging modalities, all these techniques cannot always be relied upon to provide a definitive diagnosis, in particular in the absence of a visible tumor mass [3]. In addition, it is well known that not all hilar obstructions are due to HCCA and alternative diagnosis that mimic HCCA may count for up to 25 % of all hilar obstructions [4-7]. Benign strictures for example, occasionally manifest as focal areas of wall thickening that obstruct the lumen and, thus, mimic malignant strictures. Approximately 16 % (range, 3.4-58.6 %) of patients initially diagnosed with hilar cholangiocarcinoma proved to have a benign stricture [3-20]. Biopsy is so often nondiagnostic that decisions about therapy are usually made on the basis of the imaging tests and lack of evidence for some other disease [3, 4, 21-26]. Although specific radiographic features, such as absence of tumor mass, smooth concentric pattern or tapering of the bile duct, can be associated with benign lesions, none can unequivocally exclude the presence of malignancy [6]. As a result, differentiating HCCA related biliary obstructions (Fig. 9.1) from obstructions caused by other malignant (Figs. 9.2 and 9.3) and benign (Figs. 9.4 and 9.5) lesions remains a challenge. Because the majority of biliary strictures at the liver hilum in the absence of previous surgery are usually malignant in nature and presumed to be due to HCCA, a reasonable approach is to assume the presence of HCCA until proved otherwise [15, 27-29]. However, surgeons should always be aware of the possibility of other disease particularly a benign disease and advise their patients appropriately. The diagnosis is much less specific than is generally thought, so there is considerable opportunity for mismanaging such patients. Although it has always been clear that basing the diagnosis on indirect evidence would occasionally be incorrect, a 25 % rate of false diagnosis by a team of highly specialized clinicians who encounter many such complicated cases is higher than most would have expected. Alternative diagnosis with proximal biliary obstruction mimicking HCCA is present in such a proportion of patients that it really deserves a place in the differential diagnosis of biliary obstruction. Differentiating HCCA from other causes of obstructive jaundice is important because of the differences in treatment. Curative surgical therapy for HCCA requires bile duct resection with concomitant major hepatectomy and caudate lobe resection or neoadjuvant chemoradiation, followed by liver transplantation in highly selected patients [30, 31]. This type of surgery is generally not necessary for benign conditions and generally not warranted for metastatic or other non-HCCA malignancies. Thus, preoperative precise characterization of obstructive jaundice due to hilar obstruction has important clinical implications. It would potentially improve planning for surgery and may prevent subjecting some patients to major and risky surgical interventions unnecessarily.