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Fine Needle Aspiration of Squamous-Lined Cysts of the Pancreas
Abstracts 183 Fine Needle Aspiration of Squamous-Lined Cysts of the Pancreas Christopher VandenBussche, MD, PhD, Zahra Maleki, MD. Pathology, The Johns Hopkins Medical Institutions, Baltimore, Maryland Introduction: Squamous-lined cysts (SLC) in the pancreas are rare and include lymphoepithelial cysts (LEC), dermoid cysts (DC), epidermoid cysts (EC), and squamoid cysts of pancreatic ducts (SCPD). These lesions are benign and they usually do not recur or progress. The differential diagnosis of pancreatic cystic lesions seen on imaging is broad and includes both benign and malignant conditions. While certain radiological and clinical features are suggestive of particular entities, a definitive diagnosis requires microscopic examination of the lesions. Fine needle aspiration (FNA) of pancreatic lesions is routinely used to provide cytologic material for diagnostic purposes. Due to sparse cellularity of cystic lesions, a definitive diagnosis on FNA material can be challenging. Previously only rare case reports and small case series have been published describing the FNA findings in these entities. Materials and Methods: The hospital laboratory information system was searched for surgically excised SLC from the pancreas. A total of 24 specimens were identified: 18 LEC, four EC, and one DC. No cases of SCPD were identified. We then searched for FNA specimens that were taken from these patients prior to surgical excision. A total of nine FNA specimens were identified: six from LEC, two from EC, and one from DC. The DC specimen slide was no longer available for review. Radiologic, clinical, and pathologic information for each specimen was collected. The FNA slides were reviewed for cytomorphological features and comparison with the surgical pathology material. Results: The majority of lesions (83%) were found in males, with a mean age of 55 (range: 46-73) years. Patients with EC were slightly younger than those with LEC (mean: 51 and 56 years). The cyst size differed between EC and LEC (mean: 2.5 cm and 4.9 cm; range: 1.5-4.5 cm and 1.5-16.0 cm). Of the seven individuals with FNA material reviewed in this study, 5 underwent a distal pancreatectomy and 2 underwent a Whipple procedure to resect their lesions. On morphological review, all lesions appeared hypocellular and contained single nucleated and anucleate mature squamous cells, macrophages, and varying amounts of lymphocytes. Benign fragments of squamous epithelium were found in half (3/6) of LEC cases and one EC specimen. Amorphous debris was found in all cases. Keratin was found in one LEC and one EC case. Only two LEC cases contained cholesterol crystals. No nuclear atypia or necrosis was noted. Conclusions: FNA specimens from SLC may initially appear non-diagnostic due to their relative scant cellularity and the presence of debris, gastrointestinal contamination, and non-specific cells such as macrophages and lymphocytes. Hypocellular specimens from cystic lesions and the presence of single anucleate and/or nucleate squamous cells are suggestive of a SLC. Acellular debris, crystals, macrophages, and lymphocytes are commonly found in LEC and EC. While lymphocytes are abundant in LEC lesions in surgical resections, this finding is not often well represented on FNA. Distinguishing LEC from EC and other SLC is usually not possible on FNA. In the proper clinical and radiographic setting and a combination of features suggesting a SLC, a differential diagnosis can be given along with a morphological description. An appropriate diagnosis will affect patient management, decrease patient anxiety, and prevent aggressive surgical procedures. 184 Fluorescence In Situ Hybridization (FISH) Results Identify Primary Sclerosing Cholangitis (PSC) Patients at Highest Risk of Cholangiocarcinoma when Routine Cytology is Equivocal Emily Barr Fritcher, CT(ASCP)MB1, Jesse Voss, CT(ASCP)MB1, Amy Clayton, MD1, Kevin Halling, MD, PhD1, Jayant Talwalkar, MD2, Gregory Gores, MD2, Benjamin Kipp, PhD1. 1Anatomic Pathology, Mayo Clinic, Rochester, Minnesota; 2Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota Introduction: Primary sclerosing cholangitis (PSC) is a chronic, inflammatory condition of the pancreatobiliary tract that confers a 10% lifetime
S101 risk of cholangiocarcinoma (CCA). Therefore, PSC patients are closely monitored for CCA and undergo endoscopic evaluation with brushings when clinically indicated (e.g. new stricture, abnormal liver chemistry values). An equivocal (i.e. atypical or suspicious) routine cytology result in this context presents a dilemma for clinicians and complicates patient management. The aim of this study was to evaluate the clinical outcome of PSC patients with equivocal cytology based on the associated fluorescence in situ hybridization (FISH) result. Materials and Methods: Pancreatobiliary brushings from PSC patients were collected, divided, and evaluated by routine cytology and FISH per standard practice between 2003 and 2010. Routine cytology slides were diagnosed as negative, atypical, suspicious, or positive. FISH was performed using UroVysionTM (Abbott Molecular, Des Plaines, IL) and specimens with at least 5 cells displaying gain of 2 probes were diagnosed as polysomy. Patients with an equivocal (atypical or suspicious) cytology result were retrospectively identified. Medical records were reviewed to determine clinical outcome. The gold standard for malignancy included positive biopsy, positive fine needle aspiration, subsequent positive cytology, or a mass lesion identified by imaging. For patients without malignancy, only those with at least 2 years of follow-up time were included. Results: We identified 122 PSC patients (88 males, 34 females) with equivocal routine cytology and adequate follow-up time. Forty-eight patients (39%) had cancer on follow-up including CCA (nZ44), pancreatic cancer (nZ2), gallbladder cancer (nZ1), and lymphoma (nZ1). The median follow-up was 4.3 years for those without malignancy. Polysomy was detected by FISH in 33 (27%) specimens, 28 of which had cancer (85%). Twenty of 89 (22%) patients with nonpolysomy had cancer. There was a significant difference in time to the diagnosis of cancer between patients with polysomy and those with nonpolysomy FISH results (P<0.0001), Figure 1. For patients with polysomy FISH, there was not a significant difference in the proportion of patients with cancer between atypical and suspicious cytology results (82% vs. 88%, PZ0.68). Likewise for patients with non-polysomy FISH, there was not a significant difference in the proportion of patients with cancer between atypical and suspicious cytology results (18% vs. 31%, PZ0.18).
Figure 1 Time to the Diagnosis of Cancer for Patients with Primary Sclerosing Cholangitis (PSC) and Equivocal Cytology Based on the Corresponding Fluorescence In Situ Hybridization (FISH) Result.
Conclusions: The diagnosis of CCA can be very challenging in patients with PSC. Radiology is complicated by strictures that may mimic malignancy. Pathology is complicated by inflammatory changes that may cause equivocal cytology results. The findings of this study suggest that patients with PSC and equivocal routine cytology are at greatest risk for CCA if the corresponding FISH result is polysomy and should be managed accordingly. This data also indicates that the likelihood of cancer for PSC patients with non-polysomy FISH is similar between atypical and suspicious routine cytology diagnoses.
S101 risk of cholangiocarcinoma (CCA). Therefore, PSC patients are closely monitored for CCA and undergo endoscopic evaluation with brushings when clinically indicated (e.g. new stricture, abnormal liver chemistry values). An equivocal (i.e. atypical or suspicious) routine cytology result in this context presents a dilemma for clinicians and complicates patient management. The aim of this study was to evaluate the clinical outcome of PSC patients with equivocal cytology based on the associated fluorescence in situ hybridization (FISH) result. Materials and Methods: Pancreatobiliary brushings from PSC patients were collected, divided, and evaluated by routine cytology and FISH per standard practice between 2003 and 2010. Routine cytology slides were diagnosed as negative, atypical, suspicious, or positive. FISH was performed using UroVysionTM (Abbott Molecular, Des Plaines, IL) and specimens with at least 5 cells displaying gain of 2 probes were diagnosed as polysomy. Patients with an equivocal (atypical or suspicious) cytology result were retrospectively identified. Medical records were reviewed to determine clinical outcome. The gold standard for malignancy included positive biopsy, positive fine needle aspiration, subsequent positive cytology, or a mass lesion identified by imaging. For patients without malignancy, only those with at least 2 years of follow-up time were included. Results: We identified 122 PSC patients (88 males, 34 females) with equivocal routine cytology and adequate follow-up time. Forty-eight patients (39%) had cancer on follow-up including CCA (nZ44), pancreatic cancer (nZ2), gallbladder cancer (nZ1), and lymphoma (nZ1). The median follow-up was 4.3 years for those without malignancy. Polysomy was detected by FISH in 33 (27%) specimens, 28 of which had cancer (85%). Twenty of 89 (22%) patients with nonpolysomy had cancer. There was a significant difference in time to the diagnosis of cancer between patients with polysomy and those with nonpolysomy FISH results (P<0.0001), Figure 1. For patients with polysomy FISH, there was not a significant difference in the proportion of patients with cancer between atypical and suspicious cytology results (82% vs. 88%, PZ0.68). Likewise for patients with non-polysomy FISH, there was not a significant difference in the proportion of patients with cancer between atypical and suspicious cytology results (18% vs. 31%, PZ0.18).
Figure 1 Time to the Diagnosis of Cancer for Patients with Primary Sclerosing Cholangitis (PSC) and Equivocal Cytology Based on the Corresponding Fluorescence In Situ Hybridization (FISH) Result.
Conclusions: The diagnosis of CCA can be very challenging in patients with PSC. Radiology is complicated by strictures that may mimic malignancy. Pathology is complicated by inflammatory changes that may cause equivocal cytology results. The findings of this study suggest that patients with PSC and equivocal routine cytology are at greatest risk for CCA if the corresponding FISH result is polysomy and should be managed accordingly. This data also indicates that the likelihood of cancer for PSC patients with non-polysomy FISH is similar between atypical and suspicious routine cytology diagnoses.