Maybe look at 38760. You also need a 78 modifier because you're still in the global period of the first surgery. Here's the description of the procedure from SelectCoder:
A superficial inguinofemoral lymphadenectomy is performed in a separate procedure. In 38760, the procedure is performed with excision of Cloquets node. Cloquets node is the deep inguinal lymph node that represents the transitional zone between the inguinal and iliac region. An incision is made parallel to the inguinofemoral ligament and carried down to Camper¦s fascia. Skin flaps are elevated while simultaneously separating the flaps from the underlying fat pad. Deep tissues at the superior aspect of the inguinal region are dissected. Cloquets node is identified, excised and frozen section performed. The fat pad containing nodal tissue is elevated and mobilized down to the inferior margin of the inguinal ligament. Dissection continues into the femoral triangle. The cribiform fascia is opened. Once the nodal tissue over the common femoral vein has been completely freed the inguinofemoral nodal tissue is removed as a single specimen. In 38765, inguinofemoral lymphadenectomy is performed as described above. If Cloquets node is positive for malignancy, pelvic lymphadenectomy including excision of external iliac, hypogastric, and obturator nodes is also performed. The abdomen is incised and without opening the peritoneum the pelvic lymph nodes on the side of the malignancy are explored. Taking care to preserve the genitofemoral nerve and psoas muscle, fatty tissue is stripped from the mid-portion of the common iliac vessel and along the internal and external iliac vessels to the level of the circumflex iliac vein. Iliac, hypogastric and obturator nodes are excised and sent for separately reportable pathology evaluation. The groin and abdominal incisions are closed in layers.
Hope that's helpful!
