Formalin pigment artifact deposition in autopsy tissue: predisposing factors, patterns of distribution and methods for removal

The Impact of Pre-analytical Quality Initiatives on Cholangiocarcinoma Diagnostics in Thailand

Cholangiocarcinoma (CCA) is the most prevalent malignancy in Thailand, with unfortunate late diagnosis and frequent metastatic disease outcomes. An accurate tissue diagnosis is the first and most important step in the treatment of CCA. Tissue quality and preservation during the pre-analytical phase play major roles in the proper histological evaluation and potential biomarker testing. This study evaluated the impact of using the “Cholangiocarcinoma Screening and Care Program (CASCAP)” container, as an innovative tool to address pre-analytical challenges faced by pathology laboratories in Thailand. This is a comparison study examining the quality of CCA specimens using the CASCAP container vs. the conventional method, using hematoxylin and eosin (H&E) and immunohistochemistry (IHC). CCA tissue quality using the CASCAP container significantly reduced artifact deposition while improving the cellular structure and nuclear and cytoplasmic morphologies. The immunohistochemical expression of cytokeratin 19 (CK19), a prognostic marker in CCA, significantly improved in the CASCAP container group in comparison with the conventional method. This innovation is proven to significantly enhance the CCA tissue quality diagnostics and prognostic biomarker testing, hence improving overall cancer care, diagnosis, and treatment in Thailand.

Renal Tubular Epithelial Subnuclear Vacuolization in Hypothermia and Diabetic Ketoacidosis-A Retrospective Autopsy Study

ABSTRACT

Subnuclear vacuolization of the renal tubular epithelium refers to discrete lipid vacuoles displacing the nuclei toward the lumen. This phenomenon has been associated with conditions sharing fatal ketoacidosis as a common denominator. This retrospective study aimed to investigate renal tubular epithelial subnuclear vacuolization and other postmortem examination findings in fatal hypothermia and diabetic ketoacidosis (DKA) cases.Fourteen cases with hypothermia and 19 cases with DKA were included. More cases with DKA had focal or diffuse subnuclear vacuolization compared with hypothermia cases (89% vs 43%; P = 0.007). In 6 cases with DKA, formalin pigment was detected within subnuclear vacuoles, whereas no case with hypothermia had formalin pigment deposition. Comparative analyses of hypothermia and DKA cases revealed further differences: Vitreous beta-hydroxybutyrate was higher in the DKA group compared with the hypothermia group (P = 0.044), whereas blood ethanol concentrations were higher in the latter (P = 0.008). Hypothermia cases were older compared with the DKA cases (P = 0.022).When all cases were included in the statistical analysis, cases with subnuclear vacuolization had higher vitreous beta-hydroxybutyrate and blood ethanol concentrations (P = 0.029 and 0.023, respectively). The findings corroborate the results of previous studies suggesting a link between subnuclear vacuolization and increased levels of ketoacidosis.

Pitfalls and Caveats in Applying Chromogenic Immunostaining to Histopathological Diagnosis

Chromogenic immunohistochemistry (immunostaining using an enzyme-labeled probe) is an essential histochemical technique for analyzing pathogenesis and making a histopathological diagnosis in routine pathology services. In neoplastic lesions, immunohistochemistry allows the study of specific clinical and biological features such as histogenesis, behavioral characteristics, therapeutic targets, and prognostic biomarkers. The needs for appropriate and reproducible methods of immunostaining are prompted by technical development and refinement, commercial availability of a variety of antibodies, advanced applicability of immunohistochemical markers, accelerated analysis of clinicopathological correlations, progress in molecular targeted therapy, and the expectation of advanced histopathological diagnosis. However, immunostaining does have various pitfalls and caveats. Pathologists should learn from previous mistakes and failures and from results indicating false positivity and false negativity. The present review article describes various devices, technical hints, and trouble-shooting guides to keep in mind when performing immunostaining.