Primary cutaneous B cell lymphoma--leg type (NEW EORTC--WHO classification), with nasal sinuses involvement

Area of Science:

• Dermatology and Hematology
• Oncology
• Pathology

Background:

• Primary cutaneous B-cell lymphomas (CBCLs) are rare hematologic malignancies with evolving classification systems.
• Existing controversies in CBCL classification are addressed by updated European Organisation for Research and Treatment of Cancer (EORTC) and World Health Organization (WHO) guidelines.
• The new joint WHO-EORTC classification integrates histopathological and anatomical features for improved diagnostic accuracy.

Observation:

• A case of an elderly male patient presenting with a leg-dominant cutaneous lymphoma of B-cell origin is described.
• The patient uniquely exhibited involvement of the nasal sinuses alongside typical leg lesions.
• Immunohistochemical staining confirmed features consistent with 'Cutaneous lymphoma - Leg Type'.

Findings:

• The patient's clinical presentation and histopathological findings align with the 'Cutaneous lymphoma - Leg Type' designation.
• The unique nasal sinus involvement in this case provides new insights into the potential extranodal manifestations of this CBCL subtype.
• The case supports the applicability and robustness of the new joint WHO-EORTC classification in diagnosing complex CBCL presentations.

Implications:

• This case highlights the importance of considering extranodal sites, such as nasal sinuses, in the diagnosis of cutaneous B-cell lymphomas.
• The findings underscore the utility of the integrated WHO-EORTC classification for accurately categorizing rare and atypical CBCL cases.
• Further research into the diverse clinical spectrum and potential extranodal spread of cutaneous B-cell lymphomas is warranted.