Undifferentiated carcinoma of the pancreas with osteoclast-like giant cells, a two cases report.

INTRODUCTION AND IMPORTANCE: Fine needle aspiration is the standard method for the pathological evaluation of pancreatic masses. In the following context, rare variants of such masses might present a challenge. Our goal is to describe the clinical, cytological, and histological findings of two cases of undifferentiated carcinoma with osteoclast-like giant cells (UCOCGC) a rare variant of pancreatic ductal adenocarcinoma (PDAC). CASE PRESENTATION: Two cases were identified. Cytological findings exhibit similarities between the two cases. One patient received multiple chemotherapy regimens and a surgery and recurred within three years of diagnosis, while the other succumbed to cholangitis resulting from hepatic metastases a year after their initial surgery. DISCUSSION: UCOCGC is a rare variant of pancreatic cancer, characterized by a unique cytological aspect. Recognizing this variant is essential considering its distinct prognosis compared to usual pancreatic adenocarcinoma. CONCLUSION: We presented two cases of UCOCGC a rare pancreatic cancer variant, exposing diagnostic particularities and clinical evolution.

Bone Marrow Immunohistochemistry and Flow Cytometry in the Diagnosis of Malignant Hematologic Diseases With Emphasis on Lymphomas: A Comparative Retrospective Study.

We aim to evaluate the degree of agreement between immunohistochemistry (IHC) and flow cytometry (FC) in the diagnosis of malignant hematologic diseases, mainly lymphomas. A total of 260 bone marrow biopsies, 255 bone marrow aspirates, and 5 other suspensions of 260 patients used for diagnosis of a hematologic malignancy between 2009 and 2012 with both, IHC and FC, were retrospectively analyzed. Overall there is a substantial degree of agreement (κ=0.69) between IHC and FC. Chronic lymphocytic leukemia/small lymphocytic lymphoma, mature T-cell neoplasms, acute leukemias, and myelodysplastic syndromes had the highest concurrence rates (>80%). In nonconcordant cases, an IHC provided diagnosis in 25.4%, and an FC in 4.6%. Lymphomas were diagnosed by an IHC only in 51% of the cases. Both methods have good concurrence rates and are complementary. An IHC has the advantage of combining markers, morphology, and tissue immunoarchitecture, which is beneficial in the diagnosis of lymphomas. An FC is required in leukemias as it is faster and plays an important role in minimal residual disease.

Evaluation of PACE4 isoforms as biomarkers in thyroid cancer.

BACKGROUND: To date, no single molecular marker has been demonstrated as clinically useful in differentiating malignant from benign thyroid nodules when a fine needle aspiration falls in the "unknown significance" categories of the Bethesda Classification. PACE4, a member of the proprotein convertase family of enzymes, has been shown to play a major role in the pathogenesis of prostate cancer, through the formation of an oncogenic isoform named PACE4-altCT. PACE4 isoforms have also been suggested to play a role in other cancers, including thyroid cancer, but have never been investigated in a detailed manner. Our objective is to compare the histochemical distribution of the two major PACE4 isoforms in benign and malignant thyroid nodules, in order to determine their potential usefulness as discriminatory biomarkers. METHODS: Thyroid tissues of patients who underwent thyroidectomy were classified according to final pathology. Corresponding tissue sections were immunostained, using two previously validated antibodies raised against the C-terminal end of the two PACE4 isoforms, namely the full-length PACE4 protein (PACE4-FL) and its alternative isoform (PACE4-altCT). Nodules were compared with adjacent normal parenchyma and immunostaining was rated as "low" or "high" by a head and neck pathologist. RESULTS: Non-lesional thyroid parenchyma did not express PACE4-FL (p = 0.002). As a group, malignant (n = 17) nodules expressed PACE4-FL significantly more than benign (n = 24) nodules (percentage of high immunostaining: 52.9% vs 4.2%; p = 0.001). Reciprocally, there was a statistically lower expression of PACE4-altCT in malignant nodules than in adjacent non-lesional parenchyma (p = 0.014). The specificity of a high PACE4-FL immunostaining in determining malignancy was 95.8% (95% CI, 78.9% to 99.9%). CONCLUSION: This study supports the previously described relationship between PACE4-FL and PACE4-altCT through alternative splicing. It also suggests that PACE4-FL is a promising biomarker for thyroid malignancy. Its high specific expression for malignancy could make it an interesting "rule in" test for thyroid cancer. Further prospective, quantitative studies are currently being designed to address how measurements of PACE4 isoforms could be used in a clinical setting. TRIAL REGISTRATION: This study does not report the results of a health care intervention on human participants. It was nonetheless registered on ClinicalTrials.gov under reference number NCT03160482 .