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SEER Inquiry System - Report
Produced: 06/22/2026 12:14 PM
Question 20130118
Inquiry Details
References:
Heme & Lymph Manual & DB
Question:
Primary site--Heme & Lymphoid Neoplasms: How is the primary site coded for a diagnosis of Langerhans cell histiocytosis with extensive bony metastatic disease and lymphadenopathy? See Discussion.
Discussion:
Patient was diagnosed with LCH on a biopsy of the right femur. Imaging showed extensive bony metastatic disease, extensive infiltrative perinephritis, encasement of both kidneys, renal hilar, retroperitoneal and periaortic lymphadenopathy. The right femur biopsy pathology report did not state this was metastatic.
Answer:
Updated May 2026
In the Heme DB, there is a note in 9751/3 that states if primary site cannot be determined for LCH, code the primary site to C419 [bone, NOS].
This patient has widely metastatic disease. Per the Abstractor Notes section, Langerhans cell histiocytosis arises in the bone and many times can involve multiple bones, along with other organs and lymph nodes. Although the right femur was biopsied, this does not prove that the primary site is the femur [C402] because the patient has what was described as extensive bony metastatic disease.
Cancer Site Category:
Heme & Lymphoid Neoplasms
Data Item Category:
Primary site
Other Category:
N/A
Year:
2013
