Determining the suitability of bio-specimens obtained by fine needle aspiration biopsy at a tertiary hospital in Malawi for immunocytochemical assessment

Mulenga, Maurice (2022-04)

Thesis (MSc)--Stellenbosch University, 2022.

Thesis

ENGLISH SUMMARY: Fine-needle aspiration biopsy (FNAB) is a quick, economical, least invasive and easy to perform a minor surgical procedure. In resource-limited settings, FNAB is of utmost importance in providing a rapid diagnosis that facilitates timely and correct institution of treatment. The FNAB smear preparation provides an opportunity for either rapid on-site evaluation or routine diagnosis if ancillary tests are necessary to establish a specific diagnosis. Cell blocks (CB) prepared from FNAB specimens improve the diagnostic yield, increase the sensitivity and reduce false-positive interpretations of detecting a malignant neoplasm. In addition, CB allow for additional morphological evaluation with a better architectural pattern, enable the performance of numerous ancillary diagnostic studies, including immunocytochemistry and molecular studies and offer the storage of material that can be used for future research studies. Delays in fixing the cell block have been challenges in various cell block preparatory techniques. However, a special alcohol-based fixative, commercially available solution called CytoRich Red® (CRR) has been described to be comparative to liquid-based cytology due to its effectiveness in lysing red blood cells, reducing background material, and improving staining qualities of the nucleus and cytoplasm in routine preparations of non-gynaecological material in suspension or fluids. Despite this breakthrough, there is a paucity of data on the suitability of CRR cell blocks for immunocytochemical and DNA assessment from FNAB material obtained from solid tumours. This study aimed to establish and confirm the suitability of CytoRich Red® Cell Blocks and FNAB biospecimens obtained and prepared at Kamuzu Central Hospital, Lilongwe, Malawi, for cytomorphological and immunocytochemical assessment. This study analysed 144 cell blocks and 128 FNAB smears. It is one of the first within sub-Saharan Africa to describe diagnostic efficacy from FNAB specimens obtained from various superficial and deep masses fixed in CRR. It describes the advantage of using an alcohol-based fixative immediately to reduce pre-fixation time lag. This study showed that CRR-fixed cell blocks improve sensitivity and architectural preservation, and immunocytochemical staining characteristics of the aspirate compared to routine FNAB smears. It is envisioned that CRR-fixed cell blocks will be a source of extractable, stable and usable DNA that supports research in biorepositories and biobanks.

AFRIKAANS OPSOMMING: Fyn naald aspirasie biopsie (FNAB) is 'n vinnige, koste doeltreffende, minimaal indringende en maklike prosedure. FNAB is veral belangrik in die verskaffing van 'n vinnige diagnose wat tydige en korrekte instelling van behandeling fasiliteer. Die FNAB-smeervoorbereiding bied 'n geleentheid vir 'n vinnige roetine diagnose by die pasiënt en die besluit of aanvullende toetse nodig is om 'n spesifieke diagnose te vestig. Selblokke (SB) wat uit FNAB-monsters voorberei is, verbeter die diagnostiese opbrengs, verhoog die sensitiwiteit en verminder vals positiewe interpretasies van die opsporing van maligne neoplasmas. Daarbenewens maak SB voorsiening vir addisionele morfologiese evaluering met 'n beter argitektoniese patroon, wat die uitvoer van talle aanvullende diagnostiese studies moontlik maak, insluitend immunositochemie en molekulêre studies en die berging van materiaal wat gebruik kan word vir toekomstige navorsingstudies. Vertragings in die fiksering van die selblok is bekend as een van die uitdagings in verskillende selblok voorbereidende tegnieke. 'n Spesiale alkohol gebaseerde fikseermiddel is kommersieel beskikbaar as 'n oplossing genaamd CytoRich Red® (CRR). Hierdie oplossing vergelyk goed met vloeibare gebaseerde sitologie omdat dit rooibloedselle doeltreffendheid liseer, agtergrondmateriaal verminder en kleurkwaliteite van die kern en sitoplasma verbeter in roetine-voorbereidings van nie-ginekologiese materiaal in suspensie of vloeistowwe. Ten spyte van hierdie deurbraak is daar gebrekkige inligting oor die geskiktheid van CRR-selblokke vir immunositochemiese en DNA-assessering van FNAB-materiaal wat uit soliede neoplasmas verkry word. Die doel van hierdie studie was om die geskiktheid van CytoRich Red® Cell Blocks en FNAB monster wat by die Kamuzu Sentrale Hospitaal, Lilongwe, Malawi verkry en voorberei is, te evalueer vir sitomorfologiese en immunositochemiese assessering. Hierdie studie het 144 selblokke en 128 FNAB-smere ontleed. Dit is een van die eerste studies om die diagnostiese doeltreffendheid te beskryf van FNAB monsters, verkry uit verskeie oppervlakkige en diep massas, wat in CRR fikseer is. Die resultate bevestig die voordeel om onmiddellik 'n alkohol gebaseerde fikseermiddel te gebruik om pre-fiksasie vertragings te verminder. Hierdie studie het getoon dat, in vergelyking met roetine FNAB-smere, die CRR-gefikseerde selblokke die sensitiwiteit, morfologiese en argitekturele gehalte, asook die immunositochemiese kleuringseienskappe van die aspiraat verbeter. Daar word voorsien dat CRR-gefikseerde selblokke 'n bron bied vir die ekstraksie van stabiele en bruikbare DNA wat navorsing in biobanke kan ondersteun.

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