What are the next steps for a patient with a history of intestinal lymphoma, pleural-based masses, and prostatomegaly?

Management of Pleural-Based Masses in a Patient with History of Intestinal Lymphoma

Immediate Recommendation

The patient requires a CT-guided or thoracoscopic biopsy of the pleural-based masses to establish a definitive diagnosis, as these findings could represent recurrent lymphoma, mesothelioma, or metastatic disease. 1

Assessment of Current Findings

The patient presents with:

• History of intestinal lymphoma
• CT neck showing a partially visualized pleural-based mass (12 x 24 mm) in the left pulmonary apex
• CT CAP showing:
  • Stable focal pleural thickening along the anterior right upper lobe
  • Pleural-based oblong well-defined mass in the posterior left upper lobe (unchanged since 4/2020)
  • Sub-5 mm pulmonary nodule in the right middle lung lobe
  • Prostatomegaly indenting urinary bladder base

Diagnostic Algorithm

1. Tissue Diagnosis is Essential

   • Pleural-based masses in a patient with lymphoma history require histopathological confirmation 1
   • Cytologic evaluation of pleural fluid (if present) can be an initial screening test but is not sufficiently sensitive for definitive diagnosis 1

2. Biopsy Approach

   • Thoracoscopic biopsy is preferred when accessible as it provides the highest diagnostic yield (>95%) 1
   • CT-guided core biopsy is a reasonable alternative for pleural-based masses when thoracoscopy is not feasible 1
   • Multiple biopsies from different locations should be obtained to account for tumor heterogeneity 1

3. Imaging Considerations

   • PET-CT should be performed before any invasive procedure to assess for metabolic activity and guide biopsy site selection 1
   • PET-CT is particularly valuable for determining whether metastatic disease is present 1
   • MRI is not routinely recommended for pleural masses except for specific anatomical areas like the lung apex 2

Evaluation of Prostatomegaly

The finding of prostatomegaly requires separate evaluation:

• Prostate-specific antigen (PSA) testing
• Digital rectal examination
• Consider prostate biopsy if PSA is elevated or examination is suspicious
• Lymphoma can rarely involve the prostate and should be considered in the differential diagnosis 3

Diagnostic Considerations

Potential Diagnoses for Pleural Masses

1. Recurrent lymphoma - Most likely given patient history
2. Malignant pleural mesothelioma - Consider if history of asbestos exposure
3. Metastatic carcinoma - From another primary site
4. Benign pleural disease - Less likely given the history

Important Caveats

• Pleural fluid cytology alone is insufficient for diagnosis of mesothelioma or lymphoma 1
• Core biopsies should be of sufficient size and depth to allow for immunohistochemical staining 1
• Lymphoma involving the prostate is rare but should be considered in patients with a history of lymphoma 3

Management Plan

1. Immediate Steps

   • PET-CT scan to assess metabolic activity of pleural masses and evaluate for other sites of disease 1
   • CT-guided or thoracoscopic biopsy of the most accessible or metabolically active pleural mass 1

2. If Lymphoma is Confirmed

   • Staging according to the Lugano classification 1
   • Bone marrow biopsy to complete staging
   • Treatment with appropriate chemotherapy regimen based on lymphoma subtype
   • Consider rituximab-containing regimen for B-cell lymphomas 4

3. If Mesothelioma is Confirmed

   • Multidisciplinary team evaluation including radiation oncologists, surgeons, medical oncologists 1
   • Staging according to the International Mesothelioma Interest Group TNM system 1
   • Treatment options may include surgery, radiotherapy, and/or chemotherapy 1

4. For Prostatomegaly

   • Urological evaluation with PSA testing
   • Consider prostate biopsy if PSA elevated or suspicious DRE
   • If lymphoma involvement is suspected, coordinate treatment with hematology

Follow-up Plan

• After definitive diagnosis, follow-up imaging should be performed according to disease-specific guidelines
• For lymphoma, CT scans are typically performed every 3-6 months for the first 2 years
• PET-CT may be used for response assessment in FDG-avid lymphomas 1

Remember that the definitive diagnosis through biopsy is the critical first step that will determine all subsequent management decisions for this patient with a complex presentation.