Primary pleural lymphoma: a case report

¹Pulmonology Department, Faculty of Medicine and Pharmacy of Tangier, Tangier-Tetouan-Al Hoceïma University Hospital Center, Abdelmalek Essaadi University, Tangier, Morocco, ²Pulmonology Department, Castres-Mazamet Hospital, Castres, France, ³Pulmonology Department, Toulouse University Hospital, Faculty of Health, Paul-Sabatier University, Toulouse, France, ⁴Clinical Hematology Department, Faculty of Medicine and Pharmacy of Marrakesh, Cadi Ayyad University, Marrakesh, Morocco

^&Corresponding author
Ouadii Abakarim, Clinical Hematology Department, Faculty of Medicine and Pharmacy of Marrakesh, Cadi Ayyad University, Marrakesh, Morocco

Introduction    

Primary pleural lymphoma (PPL) is an exceedingly rare subtype of non-Hodgkin's lymphoma characterized by isolated pleural lymphoproliferation without involvement of other lymphoma sites. The scarcity of specific data on this entity complicates diagnosis and management, posing significant challenges for clinicians [1]. The pathogenesis of PPL remains uncertain, with hypotheses suggesting potential roles for chronic inflammation, viral infections, or immune system dysregulation in its development [2]. The latest classifications categorize PPL into two main types: primary serous lymphoma and diffuse large-cell B lymphoma associated with chronic inflammation (DLBCL-CI) [2]. Here, we present a case of PPL in a patient who exhibited an isolated pleural mass without evidence of chronic inflammatory conditions or immune deficiencies. This case underscores the complexity of diagnosing and managing PPL and emphasizes the need for further research to better understand its pathogenesis and optimize treatment strategies [2].

Patient and observation     

Patient and observation: the patient Information: the patient was 75 years old, with a background of arterial hypertension, diabetes, and active smoking estimated at 25 pack-years, and was weaned 30 years ago.

Clinical findings: on admission, the patient presented with progressively increasing right-lateral chest pain for three weeks, with occasional dry cough and B symptoms (night sweats and weight loss of -4 kg over 15 days), with no other signs. The clinical state of the patient was good, with a WHO score 1, a normal physical examination.

Diagnostic assessment: blood count was normal with a negative inflammatory workup. Lactate dehydrogenase (LDH) was normal. Cerebrospinal fluid (CSF) was negative for lymphoid or atypical cells. A thoracic angio scan showed the presence of a right pleural mass involving the posterior pleura at T4 to T6 measuring 51 mm in height, 57 mm in thickness, 44 mm in width with clear margins, non-calcified and infiltrating the 5 and 6 intercostal spaces, with the absence of any pleural or pericardial effusion. Thoracic magnetic resonance imaging (MRI) was subsequently performed to delineate the relationship between the mass and vertebral body, revealing contact between the mass and vertebral body. A bronchial fibroscopy was performed, which showed no suspicious tracheal or endobronchial abnormalities. PET scan (Figure 1) identified an intensely hypermetabolic right pleural mass with associated hyperfixating pleural effusion. A suspicious intensely hypermetabolic left obturator adenopathy was also observed, along with moderate prostatic hypermetabolism. A CT guided pleural biopsy revealed diffuse large-cell B lymphoma, MYC not overexpressed/BCL2 positive on immunohistochemistry, and a non-GCB phenotype according to Hans (Figure 2).

Diagnosis: overall, this was a pleural DLBCL complicated by epiduritis with a large tumor mass in a 75-year-old patient with aaIPI score=2, intermediate risk, and CNS-IPI index=4.

Therapeutic interventions: initial cytoreductive therapy using the COP protocol (Cyclophosphamide, Vincristine, and Prednisone) was initiated because of the neurological emergency and the large tumor mass. Follow-up spinal cord MRI revealed stable lesions. The treatment protocol approved after consultation was R-CHOP21 (Rituximab - Cyclophosphamide - Hydroxy Doxorubicin - Vincristine - Prednisone) for 6 cycles with prophylactic intrathecal chemotherapy in the 1^st cycle and 2 cycles of maintenance rituximab. A PET scan after the fourth treatment cycle and at the end of treatment showed a complete metabolic response with the disappearance of the right pleuropulmonary lesion, with a good responder profile (Deauville 1).

Follow-up and outcome of interventions: the evolution was marked by a favorable response to the treatment with good clinical improvement.

Patient perspective: during treatment, the patient was satisfied with the level of care provided to him.

Informed consent: the purpose of the study was explained to the patient, and informed consent was received before samples were collected. The patient was made aware that her medical records would be kept confidential.

Discussion     

Diffuse large-cell B lymphoma associated with chronic inflammation, predominantly affecting the elderly, stands as the most common form of non-Hodgkin's lymphoma [2,3]. While lymphomas typically involve various anatomical sites, primary oncogenesis in the pleura is rare [4,5]. Several preexisting conditions, including tuberculosis or chronic pleural inflammation, contribute to pleural lymphoma development by fostering an immunosuppressive environment [2,6]. Although DLBCL associated with chronic inflammation primarily affects older patients, the delay between inflammation onset and lymphoma development can span a decade or more [7]. The diagnosis of primary pleural lymphoma (PPL) presents challenges due to nonspecific symptoms and limited literature on this neoplasm [2]. Primary pleural lymphoma encompasses two main entities according to the 2016 WHO classification: primary serous lymphoma linked to HHV8 infection and DLBCL associated with EBV infection [7]. Immunostaining typically reveals positivity for CD45, CD19, CD20, CD79a, and markers indicative of a non-germinal center B-cell phenotype [8]. In our case, pleural biopsy markers supported a diagnosis of DLBCL with specific immunophenotypic characteristics. The treatment of pleural DLBCL remains non-standardized, with polychemotherapy, particularly CHOP protocol, being a common approach [1,9,10]. Combining rituximab with CHOP (R-CHOP) has demonstrated improved survival rates compared to chemotherapy alone, as evidenced by the MInT trial [1,9,10]. Despite the challenges in diagnosis and management, polychemotherapy achieves complete remission in approximately 35% of cases, potentially enhancing patient survival and prognosis. Overall, further research is warranted to refine treatment strategies and optimize outcomes in PPL.

Conclusion     

Primary pleural lymphoma remains a rare and complex clinical entity that presents a diagnostic and therapeutic challenge because of its non-specific symptoms and awkward anatomical localization. This case report highlights the importance of a multidisciplinary, case-specific approach in the diagnosis and management of primary pleural lymphoma.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

Youssef Farissi: conceptualization, data collection and manuscript drafting. Manuscript revision: Ouadii Abakarim, George Kouevidjin-Eppou and Julien Mazieres. Supervision: Ouadii Abakarim. All authors approved the final version of the manuscript.

Acknowledgements      

We thank all clinical staff who participated in the treatment of the patient.

Figures     

Figure 1: PET scan images showing the right pleural mass; (A, B): before treatment; (C, D): after 4 cycles of therapy

Figure 2: (A, B, C, D) pathological images of pleural biopsy showing DLBCL with CD20+ Bcl6+ Bcl2+ MUM1+ CD10-

References