Follicular lymphoma grade I, intrathoracic lymph nodes

This code signifies a low-grade, indolent non-Hodgkin lymphoma originating from follicular center B-cells, specifically located within the lymph nodes of the chest cavity. It indicates the least aggressive form of follicular lymphoma, characterized by a slow growth rate.

Apply this code when documentation confirms a diagnosis of follicular lymphoma, histologically graded as Grade I, with definitive involvement of intrathoracic lymph nodes. This typically follows biopsy and pathological examination confirming the specific grade and anatomical location.

• Ensure the pathology report explicitly states "Grade I" follicular lymphoma.
• Verify that "intrathoracic lymph nodes" (e.g., mediastinal, hilar) are documented as the primary site of involvement.
• Do not use for follicular lymphoma of other grades or extrathoracic sites; specific codes exist for those presentations.