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Erschienen in:
05.03.2018 | Letter to the Editor
Diagnostic significance of SPACE for PCIS
Erschienen in: Clinical Journal of Gastroenterology | Ausgabe 3/2018
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Sato et al, have reported successful use of serial pancreatic-juice aspiration for cytologic examination (SPACE) to diagnose pancreatic carcinoma-in- situ (PCIS) in an elderly female patient, who presented with tumor-related pancreatitis [1]. The authors conclude that SPACE is the preferred technique for early detection of PCIS, regardless of recognizable mass or detectable tumour markers.
1.
It is widely perceived that imaging has minor role in the management of PCIS. Incidentally, all potential clues to an intraepithelial neoplasm necessitating SPACE in the present case were identified by imaging: acute pancreatitis/enlargement of pancreatic tail (CT-scan); fat replacement (CT-scan); focal atrophy/hypoechogenicity (Endoscopic ultrasonography; EUS); and main pancreatic duct (MPD) stenosis (magnetic resonance cholangiopancreatography, MRCP). The next diagnostic option would have been non-invasive Positron Emission Tomography (PET) scan followed by EUS guided fine-needle aspiration (EUS–FNA) of the hypoechoic zone for tissue diagnosis.
2.
Advanced pancreatic cancer is diagnosed by gastric juice cytology in < 50% of cases. That constitutes a major limitation of endoscopic retrograde cholangiopancreatography (ERCP). (a) Was SPACE informative in this patient due to serial testing alone or was it so because of the large size of PCIS, measuring close to stage-1 tumor? (b) Can SPACE be routinely advised to establish or exclude the diagnosis of PCIS in patients with abnormal pancreatic morphology? However, with consensus on frequency and duration of sampling, SPACE appears to have potential for global acceptance as a preferred technique. It may facilitate juice analysis for cytokines, molecules of malignancy and tumor markers. Moreover, special contrasts, enhancers and dyes may be injected through endoscopic naso-pancreatic drainage catheter for PCIS imaging.
3.
Parenchymal and ductal changes are also encountered in old age, without pancreatic disease. Controversies exist about local fat replacement as a cause or effect of PCIS and whether or not it remains confined to the tumour region. Contrarily, desmoplasia is more consistent feature of pancreatic cancers so that MPD stenosis is universally regarded as predictor of malignancy. Pancreatic stellate cells undergo autocrine or pro-inflammatory cytokine (TNF-α, TGF-β, IL-1, IL-6) induced activation, leading to ductal stricture in the tumor region and fibrosis elsewhere in the pancreas. Can pancreatic elastography help in selection of candidate SPACE or EUS–FNA?
4.
The most fascinating aspect of this case report by Satoh et al., is sparing of the basement membrane by a high grade PCIS which spans between side branch and MPD for 2 cm. Can we infer that an extraordinary structural damage to the MPD had resulted simply from a “cross-talk” between cells of epithelium and submucosa, leaving all the layers intact? These expanding horizons of molecular pathology may oblige us to revisit our concepts of tumor invasion.