In the field of cytopathology, cytologists often come across a range of benign, normal cells in samples. These normal cells make up a significant proportion of the material present on a cytology slide, particularly in Pap smears of the uterine cervix, urine samples, and lung samples like bronchial brushings. However, the presence of normal cells can sometimes lead to misdiagnoses, especially in cases with reactive and metaplastic changes. Additionally, certain neoplasms can also mimic normal cytology, causing further confusion.

Today, cytology laboratories are not limited to dealing with just exfoliative specimens and superficial aspirations. With advancements in interventional radiology, as well as endobronchial and endoscopic ultrasound-guided fine needle aspirations (FNA), cytologists are increasingly encountering visceral samples. This means that normal elements from deep-seated organs are also likely to be encountered. Sometimes, unexpected normal elements may be found within cytology specimens due to contamination during an FNA procedure or inadvertent sampling of a nearby organ or anatomical structure. For example, ganglion cells may be found when a FNA is performed targeting a celiac node for cancer staging.

Despite the importance of understanding the spectrum of normal cytology, there is a lack of reference materials available on this topic for cytologists. Most cytopathology texts focus on abnormal cytology, with only a few sentences dedicated to normal cytology (euplasia). This is where “A Comprehensive Guide to Normal Cytology: Understanding and Interpreting Benign Cells” comes in. This book aims to fill the gap by providing a comprehensive resource on normal cytology.

The book will include a mixture of text and images in an atlas format. It will highlight important aspects related to cytology practice, such as clinical relevance, differential diagnoses, mimics, and pitfalls. The images will showcase a variety of cytology specimen preparations, including direct smears, liquid-based samples, touch preparations, and cell blocks. Various stains, such as Diff Quik/MGG, Papanicolaou, and H&E, will also be featured. In selected cases, the expected immunoprofile of normal cells will be addressed. Each chapter will be accompanied by a modest list of helpful and contemporary references.