Advancing diagnostic accuracy in soft tissue cytopathology through WHO guidelines

Background and objectives

Soft tissue cytopathology plays a vital role in the diagnosis and management of soft tissue neoplasms, necessitating a standardized classification system to improve diagnostic accuracy and guide clinical decision-making. This article provides a concise review of the World Health Organization (WHO) Reporting System for Soft Tissue Cytopathology and presents a practical diagnostic approach to soft tissue cytopathology.

Methods

The WHO Reporting System is reviewed in conjunction with relevant literature. The reporting system employs a six-category framework: non-diagnostic, benign, atypical, soft tissue neoplasm of uncertain malignant potential, suspicious for malignancy, and malignant. Each category is associated with a corresponding risk of malignancy and recommended clinical management guidelines. This classification aligns with the WHO Classification of Soft Tissue and Bone Tumours (5^th edition) and incorporates cytomorphologic features, ancillary studies, and clinical correlation to enhance diagnostic reproducibility and communication among pathologists and clinicians.

Results

The system supports a probabilistic approach to risk stratification, enabling more consistent diagnostic and therapeutic strategies.

Conclusions

This structured reporting system aligns with the WHO Classification of Soft Tissue and Bone Tumours (5^th edition), ensuring that cytopathological findings are reproducible, clinically actionable, and globally applicable. The approach integrates cytomorphological features, ancillary testing, and clinical correlation, emphasizing a probabilistic framework for risk stratification and decision-making. By providing clear diagnostic criteria, this system enables pathologists to contribute effectively to multidisciplinary patient management. Furthermore, advancements in molecular diagnostics, ICC, and NGS are expected to enhance the accuracy and specificity of FNAB-based diagnoses, reinforcing the role of cytopathology in the evaluation of soft tissue tumors.

A limitation of this publication is that it applies primarily to FNAB and can be extended to CNB; however, its relevance to touch imprint of soft tissue remains unclear. Given the increasing trend of obtaining CNBs of soft tissue lesions with rapid on-site evaluation for cellularity via touch imprint cytology, it would be valuable to determine whether this approach is also applicable in this context. Additionally, it is important to assess whether the clinical team supports this reporting system, as they are the primary end users with whom communication is intended. It will be interesting to examine the broader impact of this reporting system and explore its correlation with the upcoming 6^th edition of the WHO Classification of Soft Tissue and Bone Tumours in the near future.

The hope is that by following this structured reporting format, the WHO Reporting System for Soft Tissue Cytopathology will ensure FNAB diagnoses are clear, reproducible, and clinically actionable. The integration of cytomorphological features, ROM assessment, ancillary testing, and clinical correlation will enhance the diagnostic accuracy of soft tissue FNAB and facilitate appropriate patient management. This standardized approach aligns with modern risk-based classification models and will improve communication among pathologists, radiologists, and oncologists, also ensure patient safety and high quality care.

It is important that the readers of this article refer to the exact wording and specific details related to the definition for each diagnostic category, risk of malignancy (ROM), and management recommendations as provided in the WHO Reporting System for Soft Tissue Cytopathology. The explanatory content in this review article has been adapted based on the author's interpretation of the forthcoming book.