Rosai-Dorfman disease of the pancreas: Cytologic analysis of three cases presenting as pancreatic masses.

Rosai-Dorfman Disease (RDD), or sinus histiocytosis with massive lymphadenopathy, is a rare entity characterized by proliferating S100-positive histiocytes. It is most commonly found in lymph nodes with extranodal involvement usually occurring in the head and neck. Pancreatic involvement is extremely rare. The pathology department archives were searched for fine needle aspirations and pancreatic resections showing evidence of RDD. Clinicopathologic features, cytologic smears, cell blocks, immunocytochemical stains and surgical resections were reviewed. Three cases were identified. They were all females, aged 65, 69 and 75, with involvement of the pancreatic tail or head by solid masses of median size 2.3 cm (range 2.1-4.5 cm). Cytologic findings on smears included multiple histiocyte clusters resembling loosely cohesive epithelioid granulomas, singly dispersed histiocytes with moderate to marked nuclear atypia and characteristic emperipolesis. These atypical histiocytes stained positively for CD68, CD163 and S100. Smear background contained variable mixed inflammatory cells, necrotic debris and stromal fragments. The RDD diagnosis was further confirmed on pancreatic resection in two patients and core biopsy in one. The latter patient required three separate procedures before a definitive diagnosis was made. RDD of pancreas is a rare benign inflammatory condition that is diagnostically challenging on cytology. This can cause delays in cytologic diagnosis and/or misdiagnosis. Identification of characteristic cytologic features, primarily histiocytes with emperipolesis, and matching immunocytochemical profile can ensure accurate diagnosis and distinction from mimics.

RNA In Situ Hybridization for Epstein-Barr Virus and Cytomegalovirus: Comparison With In Situ Hybridization and Immunohistochemistry.

The RNAscope utilizes in situ hybridization (RISH) technology to detect single RNA molecules in a variety of tissue samples, including formalin fixed paraffin embedded (FFPE) tissues. Epstein-Barr virus (EBV) and cytomegalovirus (CMV) are found in association with neoplastic tissues and inflammatory lesions, and immunohistochemistry (IHC) or other techniques (ISH) are utilized to identify them. We compared the RNAscope RISH to ISH and IHC in the detection of EBV and CMV respectively to determine RNAscope utility in a clinical setting. Thirty-one FFPE tissues were stained by RISH to detect EBV and 24 samples of tissue for CMV. The RISH used the RNAscope (Leica BioSystems, Buffalo Grove, IL), the Bond III autostainer (Leica), and probes V-EBV and V-CMV (Advanced Cell Diagnostics, Newark, CA) as well as negative (DapB) and positive probe (PPIB) for RNA. Results were compared with those by ISH (Leica, EBV RNA probe), and IHC (CMV Dako, 1/160), respectively. RISH and ISH were concordant in 100% of cases positive for EBV by ISH (19/19). Of the cases negative for EBV by ISH, RISH showed positivity in an additional 25% of the samples (3/12). Overall concordance was 90.3% (28/31). RISH and IHC were concordant in 100% of cases positive for CMV by IHC (8/8). Of the cases negative for CMV by IHC, RISH detected positivity in an additional 50% of the samples (8/16). Overall concordance was 66.7% (16/24). RISH demonstrates increased sensitivity in the clinical setting, especially for CMV, detecting positive cells not stained by EBV ISH and CMV IHC.

Updates in Cervical Cytology: The 90-Year-Long Journey from Battle Creek to Today.

Ninety years ago, at the Battle Creek conference, Papanicolaou introduced cervical exfoliative cytology. Since then, the "Pap test" has come a long way. The discovery of a causal relationship between cervical carcinoma and HPV infection opened the door for molecular testing and immunomarkers for HPV. The Clinical Laboratory Improvement Amendments, 1988, established quality assurance and quality control programs to monitor performance of cytology laboratories. The Bethesda System for reporting cervical cytology laid the foundations for cervical cytology education, implementation of management guidelines, and further research on cervical carcinogenesis. HPV vaccine penetration in both genders remains 62% or less.