Cytomorphology of renal angiomyolipoma: performance and accuracy of touch preparation of core needle biopsy

• Published in: Journal of the American Society of Cytopathology JASC 2023-03, Vol.12 (2), p.142-152
• Main Authors: Gelarden, Ian Arthur, Gama, Alcino, Choy, Bonnie
• Format: Article
• Language: English
• Subjects: Aged; Angiomyolipoma - diagnosis; Angiomyolipoma - pathology; Biopsy, Large-Core Needle; Carcinoma, Renal Cell - pathology; Core needle biopsy; Cytomorphology; Female; Humans; Kidney Neoplasms - diagnosis; Kidney Neoplasms - pathology; Leukemia, Myeloid, Acute; Male; PEComa; Renal angiomyolipoma; Touch; Touch preparations
• ISSN: 2213-2945; 2213-2945
• DOI: 10.1016/j.jasc.2022.12.003

The recognition of renal angiomyolipoma (AML) can be challenging based on cytology preparations such as touch preparation (TP) of core needle biopsy (CNB) and fine needle aspiration. This study evaluated the cytologic features and performance of TP of CNB during rapid onsite evaluation (ROSE) of renal AML. A pathology database search was performed between 2000 and 2021 for renal CNB specimens with ROSE using TP that were primarily favored AML on preliminary impression and/or confirmed AML on CNB or subsequent resection. Twenty confirmed AML were identified (90% female, median age 65.5 years). Sixteen (80%) were deemed adequate for diagnosis at the time of ROSE, and 9 of 16 (56%) had available onsite impression: AML was favored in 4 of 9 cases (44%). Examination of TP slides revealed spindle/epithelioid cells in 20 (100%), adipose tissue in 14 (70%), and blood vessels in 3 (15%). All AML cases were subsequently confirmed by immunohistochemistry. Additionally, 3 other cases with ROSE favoring AML revealed to be “renal parenchyma with fibrosis,” clear cell papillary renal cell tumor and clear cell renal cell carcinoma. Onsite evaluation of TP ensures adequate material for diagnosis in most renal AML. Spindle/epithelioid cells were the most common component seen on TP, followed by adipose tissue. Blood vessels were rarely seen. While the recognition of AML at ROSE can be challenging, proper evaluation is important in obtaining adequate diagnostic tissue. Correlation with CNB and utilization of immunohistochemistry are crucial for arriving at the diagnosis. •Rapid onsite evaluation using touch preparations of core needle biopsies ensures adequate diagnostic material in the majority of renal angiomyolipoma (AML).•The presence of the major components of AML (spindle/epithelioid cells, adipose tissue, vessels) along with features such as intranuclear pseudoinclusions can be used to identify AML based on cytology preparations.•Recognition of AML at the time of rapid onsite evaluation can be difficult and subjected to both over interpretation as malignant and under interpretation as non-neoplastic. Correlation with core biopsy and immunohistochemistry are crucial for making the correct diagnosis.