[A case of CD56 positive T-cell lymphoma originating from mediastinal lymph nodes]

Area of Science:

• Oncology
• Pulmonology
• Infectious Diseases

Background:

• Pleural effusion presents a diagnostic challenge, particularly when initial investigations for infection are inconclusive.
• Tuberculous pleuritis is a common consideration, but other pathologies can mimic its presentation.

Observation:

• A 63-year-old man presented with fever, chest pain, and pleural effusion with high adenosine deaminase (ADA) levels.
• Initial diagnosis of tuberculous pleuritis was made, but the patient's condition worsened despite anti-tuberculosis therapy.
• Elevated soluble interleukin-2 receptor (sIL-2R) and subsequent lymph node enlargement led to a revised diagnosis.

Findings:

• Pleural effusion cytology and video-assisted thoracoscopic biopsy were initially negative for malignancy.
• Peripheral T-cell lymphoma, unspecified (WHO classification) with CD56 expression was diagnosed via lymph node biopsy and pleural effusion cytology.
• The patient responded to cyclophosphamide/doxorubicin/vincristine/prednisolone (CHOP) chemotherapy initially, but ultimately required carboplatin/ifosfamide/etoposide/dexamethasone (DeVIC) chemotherapy for complete response.

Implications:

• High ADA levels in pleural effusions, especially when unresponsive to anti-tuberculosis treatment, should raise suspicion for malignant lymphoma.
• This case underscores the need for comprehensive diagnostic evaluation in persistent pleural effusions.
• Timely diagnosis and appropriate chemotherapy are crucial for managing peripheral T-cell lymphoma.