Retroperitoneal tuberculosis

This code signifies a tuberculous infection affecting the retroperitoneal space, which is the anatomical area behind the peritoneum. This can involve lymph nodes, connective tissue, or other organs within this region, excluding specific genitourinary involvement.

Assign this code when documentation explicitly states tuberculosis of the retroperitoneum. Supporting documentation should include imaging findings (e.g., CT scan showing retroperitoneal lymphadenopathy or mass) and/or biopsy results confirming Mycobacterium tuberculosis infection in this anatomical area.

• Differentiate from genitourinary tuberculosis (A18.1x) if the infection primarily involves organs like the kidney or bladder.
• Always code the underlying tuberculosis (A15-A19) as the primary diagnosis if not already specified.
• Ensure documentation clearly specifies "retroperitoneal" to avoid confusion with other abdominal or pelvic tuberculous infections.