Case Example 12 (Multiple Primary, Histology and Primary Site)

9/23 resection of retroperitoneal mass and path shows CLL/SLL and nodular lymphocyte predominant Hodgkin Lymphoma. CT + for splenomegaly. PET with no evidence of metabolically active lymphoma. 4/24 PT has bone marrow bx + for CD5+ B-cell lymphoma compatible with known CLL/SLL

This scenario requires going through the M rules twice.

Involvement Comments
Lymph nodes Retroperitoneal
Organ involvement Spleen
Common metastatic sites Bone marrow

Coding of the case (Lymphoma schema)

Data Item-Primary #1 Coding
M Rule M5: Hodgkin and NHL diagnosed in the same biopsy
PH Rule PH14: Code 9596/3
PH18: Code to C772 when described as a retroperitoneal mass
Primary site C772: Intra-abdominal lymph nod
Histology 9596/3: Mediastinal grey lymphoma (new preferred term)
Diagnostic confirmation 1 (positive histology)
EOD Primary Tumor 600 (splenomegaly)
EOD Regional Nodes 888 (not applicable)
EOD Mets 88 (not applicable)
Summary Stage 7 (splenomegaly)
Mets at Dx Data Items (all 6) Mets at Dx-Distant lymph nodes: 8, remaining Mets at Dx data items 0
Data Item-Primary #2 Coding
M Rule M15: Use the multiple primaries calculator.
M4 does not apply since these were diagnosed at different times and different sites
PH Rule PH26: Bone marrow
Primary site C421 (bone marrow)
Histology 9823/3 (CLL/SLL)
Diagnostic confirmation 1 (positive histology)
EOD Primary Tumor 800 (bone marrow involvement)
EOD Regional Nodes 888 (not applicable)
EOD Mets 88 (not applicable)
Summary Stage 7 (bone marrow involvement)
Mets at Dx Data Items (all 6) 8 (not applicable for all)

Updated: December 2, 2025