Histologic Diagnosis of Renal Mass Biopsy.

CONTEXT.—: Core biopsy has been increasingly used for clinical decision-making in the management of patients with renal masses. The sensitivity and specificity of histologic diagnoses of renal mass biopsies depend on many factors such as adequate sampling and tissue processing, diagnostic skill and experience, and appropriate use of ancillary techniques. OBJECTIVE.—: To review the indications, emphasize the importance of obtaining adequate diagnostic material, and introduce a general diagnostic approach, in conjunction with immunohistochemistry, in diagnosis of renal mass biopsies. DATA SOURCES.—: Literature review and personal experiences in daily practice and consultation diagnosis of renal masses in a large tertiary medical center. CONCLUSIONS.—: For renal mass biopsies, it is critical to obtain adequate diagnostic material and establish a standard laboratory procedure in working with small biopsy specimens. The key for the diagnosis is to be familiar with different tumor entities with characteristic morphology and to understand the wide spectrum of tumor heterogeneity. By developing a systematic approach, one can categorize the tumor and create a sensible differential diagnosis based on the growth pattern and cellular morphology. Immunohistochemistry is particularly helpful for renal mass biopsy diagnosis in selected situations.