Neoplasm of uncertain behavior of left kidney

This code signifies the presence of an abnormal growth in the left kidney where the pathologist cannot definitively determine if it is benign or malignant. This means the cellular characteristics are ambiguous, preventing a clear diagnosis of either a non-cancerous tumor or a cancerous one. Further diagnostic workup, such as additional biopsies or imaging, is often required to clarify the nature of the neoplasm.

Apply this code when pathology reports or physician documentation describe a renal mass in the left kidney as "of uncertain behavior," "indeterminate," or "borderline." This is appropriate when the tumor exhibits some atypical features but lacks sufficient evidence for a definitive diagnosis of malignancy or benignity. Documentation should clearly specify the left kidney as the affected site.

• Ensure the documentation explicitly states "left kidney" to avoid laterality errors.
• Do not use this code if the neoplasm is definitively diagnosed as benign (e.g., D30.02) or malignant (e.g., C64.2).
• Review the pathology report carefully; if the behavior is later clarified, update the diagnosis accordingly.