Primary esophageal lymphomas

Primary esophageal lymphomas are extremely rare extranodal lymphoid neoplasms characterized by initial and predominant involvement of the esophageal wall, with no evident systemic lymphoma at the time of diagnosis. Within gastrointestinal lymphomas, the esophagus is an exceptional site because it normally contains relatively little mucosa-associated lymphoid tissue and because epithelial neoplasms are far more common in the same anatomic region. The rarity of the condition means that its clinical features and natural history are derived mainly from retrospective series and case reviews, with unavoidable limitations in the standardization of definitions, staging and treatment strategies.

Histologically, the spectrum mainly comprises B-cell lymphomas, particularly diffuse large B-cell lymphoma (DLBCL) and, less commonly, extranodal marginal zone lymphoma of MALT type. Other subtypes, including T-cell lymphomas and immunodeficiency-associated forms, have also been described but are very rare. The clinical presentation is often dominated by dysphagia, odynophagia and weight loss, with possible overlap with esophageal carcinoma or inflammatory disorders, and suspicion usually arises during gastroenterologic rather than hematologic evaluation.

Diagnosis requires endoscopy with deep biopsies and complete pathologic characterization, integrating immunohistochemistry, flow cytometry when feasible and, for relevant subtypes, cytogenetic or molecular analysis. Once lymphoma is confirmed, assessment must rigorously establish that the esophagus is the predominant site of presentation by excluding more extensive nodal or extranodal disease using functional and anatomic imaging. Treatment is generally multimodal and depends on histologic subtype and disease extent, with a central role for chemoimmunotherapy in aggressive lymphomas and for radiotherapy or selected conservative strategies in localized indolent forms, alongside nutritional support and management of local complications.

The epidemiology of primary esophageal lymphoma is defined by extreme rarity, with far fewer cases reported than for gastric and intestinal sites. Consequently, true incidence is difficult to quantify, and much of the available information comes from literature reviews in which inclusion criteria vary according to how rigorously systemic disease was excluded and whether PET and CT were available during the observation period. Clinically, every diagnosis therefore requires critical confirmation of primary origin because the esophagus may also be secondarily involved by systemic lymphoma or contiguous mediastinal disease.

Most reported cases occur in adults and older people, with broad variability because of the small numbers. Sex distribution is inconsistent across series and is affected by publication bias. The lesion may involve the proximal, middle or distal esophagus; when growth is subepithelial or infiltrative, it may mimic a wall tumor or a long-segment stricture, and presentation is often delayed because dysphagia progresses gradually.

Direct etiologic causes have not been defined. In the absence of a necessary and sufficient agent, attention focuses on risk factors and predisposing settings that promote aberrant lymphoid proliferation or reduce immune surveillance. At many extranodal sites, chronic inflammation may contribute to the development of acquired lymphoid tissue; in the esophagus, this concept is plausible but not robustly demonstrated and should be interpreted cautiously because of the lack of prospective data.

Risk factors most consistent with the literature on extranodal presentations include immunosuppression, such as uncontrolled HIV infection, iatrogenic post-transplant immunosuppression and prolonged immunomodulatory therapy, which can favor aggressive lymphomas and, in some settings, EBV-associated forms. Older age, comorbidities and chronic local inflammation may also act as nonspecific cofactors. Overall, the risk profile does not support targeted population-prevention strategies, and detection occurs mainly through symptom-guided investigation.

There are no screening programs or population-surveillance pathways for primary esophageal lymphoma because of its epidemiology and the absence of a noninvasive test with adequate diagnostic performance. Endoscopy cannot be justified as an early-detection tool for this entity because the expected yield would be negligible and the organizational and clinical burden disproportionate.

In practice, diagnosis is driven by recognition of alarm features warranting endoscopy: progressive dysphagia, persistent odynophagia, unintentional weight loss, anemia or bleeding, recurrent vomiting and unexplained retrosternal pain. In these settings, endoscopy is performed for suspected organic esophageal disease and may unexpectedly reveal a lesion compatible with lymphoma, particularly when the appearance is subepithelial or infiltrative and the mucosa is relatively preserved.

A distinct situation concerns patients with known lymphoma or significant immunodeficiency. In such cases, the objective is not to detect a primary esophageal lymphoma, but to maintain a lower diagnostic threshold for esophageal symptoms because opportunistic infection, treatment toxicity and neoplastic involvement may produce overlapping clinical pictures. The most rational strategy therefore remains appropriate and timely use of endoscopy with biopsy when clinically indicated, whereas systematic surveillance is not supported by evidence.

The biology of primary esophageal lymphomas reflects the characteristics of the lymphoma subtype presenting at the esophageal site more than any organ-specific feature. The esophagus normally contains little organized lymphoid tissue; therefore, in indolent MALT-type forms, a plausible pathogenetic premise is the acquisition of lymphoid aggregates in the setting of chronic antigenic stimulation and permissive microenvironments, followed by clonal expansion and neoplastic transformation. In aggressive forms such as DLBCL, esophageal presentation may result from transformation of an unrecognized pre-existing indolent component or from de novo development in a locally altered immune microenvironment, particularly in immunosuppressed patients.

At the molecular level, driver mechanisms depend on subtype. In aggressive B-cell lymphomas, dysregulation of B-cell receptor signaling, NF-kB pathways and proliferation and survival programs contributes to the rapidly progressive clinical phenotype. In many forms, the genetic profile affects treatment response and prognosis, making integration of morphology, immunophenotype and, when indicated, cytogenetic or molecular studies important for accurate classification according to current systems.

Most frequently reported histologic subtypes and their essential biological implications

• DLBCL: aggressive behavior, rapid growth and the need for immediate systemic treatment, with possible benefit from integrated locoregional therapy in selected cases.
• MALT lymphoma: indolent phenotype, often with a subepithelial presentation, and the possibility of conservative or locoregional strategies for localized disease.
• Other B- or T-cell lymphomas: rare events, often requiring careful evaluation for immunodeficiency or a systemic clinical pattern that must be rigorously excluded.

Histologic infiltration may be mucosal, submucosal or transmural. MALT lymphomas may present as subepithelial lesions with apparently intact mucosa, whereas aggressive forms may cause ulceration, exophytic masses or stenosis. Diagnosis requires targeted immunohistochemical panels and, when tissue permits, integration with flow cytometry and genetic studies to define subtype and exclude mimics such as undifferentiated carcinoma, GIST or neuroendocrine neoplasms.

Immunophenotype and characterization required in clinical practice

• Definition of lineage and subtype with B- and T-cell panels, including maturation and proliferation markers.
• Assessment of CD20 expression when relevant to the use of anti-CD20 antibodies in B-cell lymphomas.
• Cytogenetic or molecular studies when indicated for prognostic stratification and clarification of biologically high-risk categories.

Overall, pathogenesis is best interpreted as local expression of established lymphoma biological programs, modulated by the esophageal microenvironment and the host immune status. The clinical consequence is that optimal management requires a robust histologic diagnosis and accurate staging rather than an assumed organ-specific biology.

The clinical manifestations of primary esophageal lymphoma are often nonspecific and are dominated by symptoms caused by involvement of the wall and lumen. Progressive dysphagia is the most frequent presentation and may be associated with odynophagia and retrosternal pain. In many cases progression is subacute, with gradual worsening of tolerance to solid food followed by difficulty with liquids, mimicking epithelial neoplasms or advanced benign strictures.

Weight loss is common and may result both from reduced intake due to dysphagia and from the systemic effects of disease. Aggressive forms may cause B symptoms such as persistent low-grade fever, night sweats and marked fatigue, whereas indolent forms may be dominated by swallowing discomfort and atypical dyspepsia. Some patients present with anemia or signs of bleeding, more often when mucosal ulceration is present, while hoarseness, cough or respiratory symptoms may occur because of compression, aspiration or fistulas in very advanced disease.

Clinical presentations that most frequently lead to endoscopy

• Progressive dysphagia, particularly when associated with weight loss or retrosternal pain.
• Persistent odynophagia and rapid worsening of swallowing symptoms.
• Anemia or gastrointestinal bleeding with suspected esophageal disease.
• B symptoms or worsening fatigue with signs of organic disease.
• Cough, aspiration or signs of local complications in advanced disease.

Physical findings may be minimal in early stages. Advanced disease may produce signs of malnutrition, dehydration, pallor and, when previously unrecognized dissemination is present, hepatosplenomegaly or lymphadenopathy. Because clinical features do not distinguish the histologic subtype, endoscopic and histologic confirmation remains central to the entire diagnostic pathway.

The diagnostic work-up for primary esophageal lymphoma begins with suspicion of organic esophageal disease and proceeds through a sequence aimed at demonstrating lymphomatous nature, defining subtype and establishing extent while confirming that esophageal involvement is predominant. Suspicion arises in the presence of progressive dysphagia, odynophagia, weight loss, anemia or systemic symptoms, particularly when alarm features make empirical management inappropriate.

The decisive first-line examination is upper gastrointestinal endoscopy. Lesions may be ulcerated, exophytic, infiltrative or subepithelial; the mucosa may appear relatively preserved when growth is predominantly submucosal. For this reason, the most important technical requirement is obtaining multiple deep biopsies. In subepithelial presentations or after nondiagnostic biopsy, endoscopic ultrasonography defines the involved wall layers and guides targeted tissue sampling, increasing the likelihood of obtaining representative material.

Definitive diagnosis is pathologic and requires complete immunophenotyping. Morphology may mimic undifferentiated carcinoma or other mesenchymal neoplasms, so definition of lymphoid lineage and subtype is crucial to avoid therapeutic errors. When possible, integration with flow cytometry and genetic studies permits more precise classification and better prognostic stratification, particularly in aggressive forms. In addition to subtype, the report should include indicators of proliferative activity and, when assessable, features of local invasiveness useful for planning.

Assessment of primary esophageal origin requires accurate systemic staging. Clinical criteria have historically been proposed to define a primary gastrointestinal presentation; in modern practice, the aim is to demonstrate the absence of predominant nodal or extranodal involvement elsewhere using medical history, physical examination and dedicated imaging. Baseline imaging includes contrast-enhanced CT of the chest, abdomen and pelvis; 18F-FDG PET is particularly useful in FDG-avid lymphomas to identify occult sites and establish a baseline for response assessment. Bone-marrow evaluation is tailored to subtype and PET and laboratory findings, with hematologic integration.

From a rigorous clinicopathologic perspective, attribution of a primary esophageal presentation is based on essential elements of coherence between histology and disease distribution:

Essential clinicopathologic elements for attributing a primary esophageal presentation

• An endoscopically documented esophageal lesion with adequate tissue sampling.
• Histologic confirmation of lymphoma with immunophenotyping and subtype classification.
• Systemic imaging showing no predominant nodal or extranodal disease at another site.
• Complete clinical assessment focused on lymphadenopathy, hepatosplenomegaly and systemic symptoms.
• Early multidisciplinary review integrating endoscopic, radiologic and pathologic data.

Overall, diagnosis proceeds from endoscopic and histologic demonstration to subtype definition and staging with CT and PET, with additional targeted tests when necessary. Timeliness is crucial because misinterpretation as carcinoma may lead to inappropriate intervention, whereas correct diagnosis permits highly effective therapy for many subtypes.

Staging of primary esophageal lymphoma follows the principles used for extranodal gastrointestinal lymphomas, predominantly using the Lugano classification, derived from and adapted from Ann Arbor, and integrating PET and CT to define local extent, lymph-node involvement and distant extranodal sites. The purpose is not merely descriptive: staging guides treatment intensity and the balance between disease control and toxicity, particularly in aggressive forms.

In esophageal lymphoma, staging should include assessment of the wall and adjacent structures because local progression may cause severe stenosis or complications such as fistulas. Endoscopic ultrasonography may contribute to defining wall involvement and regional lymph nodes, whereas PET provides whole-body disease mapping and supports response assessment using international FDG-based criteria and standardized scales.

Lugano staging for gastrointestinal lymphomas applied to the esophagus

• Stage I: disease confined to the gastrointestinal tract and limited to the esophagus, as a single lesion or multiple contiguous foci within the same organ.
• Stage II: abdominal lymph-node involvement associated with the primary lesion, distinguishing nearby regional nodes from more distant abdominal stations, without distant involvement.
• Stage IIE: extension beyond the wall with contiguous involvement of adjacent structures or organs, with or without regional lymph nodes and without distant dissemination.
• Stage IV: disseminated disease with noncontiguous extranodal or distant involvement, including possible bone-marrow or visceral disease.

Prognosis depends strongly on histologic subtype and extent. Localized indolent forms may have favorable outcomes with selected locoregional or conservative strategies, whereas aggressive forms require immediate systemic treatment and prognosis is influenced by the initial response. Additional determinants include performance status, nutritional status, B symptoms, local complications and subtype-specific biological factors, including high-risk genetic profiles when present. In patients with major stenosis, bleeding or malnutrition, clinical and nutritional stabilization directly affects the ability to deliver effective therapy and therefore the overall outcome.

Treatment of primary esophageal lymphoma must be based on three axes: subtype, stage and local functional impact. In the absence of dedicated trials, strategies derive from established principles for extranodal and nodal lymphomas adapted to the esophageal setting, where dysphagia, aspiration risk and nutritional impairment may require intensive support from the outset.

For aggressive B-cell forms, particularly DLBCL, the standard approach is chemoimmunotherapy with anti-CD20-containing regimens in CD20-positive disease. In selected localized cases, integration of involved-site radiotherapy or other locoregional strategies may be considered for consolidation, balancing benefit against the risks of esophagitis and stenosis. Surgery is not a treatment mainstay but may be necessary for complications such as perforation or fistula, or when diagnosis cannot be obtained by less invasive techniques and the clinical situation requires a definitive approach.

For indolent forms such as localized MALT lymphoma, more conservative strategies may be appropriate, including low-dose radiotherapy in selected settings, anti-CD20 immunotherapy when indicated and, in particular cases, endoscopic approaches for circumscribed, technically treatable lesions, provided diagnosis and staging confirm truly localized disease. The choice should take into account recurrence risk, quality of life and the feasibility of close follow-up.

Treatment objectives and strategies according to the clinical setting

• Localized indolent disease: locoregional control and preservation of function, with selected radiotherapy or immunotherapy options and targeted nutritional management.
• Localized aggressive disease: chemoimmunotherapy as the central treatment, with possible locoregional consolidation in selected cases and PET-based response assessment.
• Advanced disease: subtype-directed systemic therapy, with control of esophageal symptoms and prevention of complications.
• Functional impairment: early clinical nutrition, management of dysphagia and prevention of aspiration to ensure treatment continuity.

Supportive management is often decisive. In patients with severe dysphagia or rapid weight loss, nutritional care with supplementation, selected enteral nutrition and strategies to reduce aspiration may be necessary before and during treatment. Interventional endoscopy, selected dilatation or esophageal stenting may be considered case by case, particularly when obstruction prevents adequate intake, taking into account the risk of perforation in infiltrated walls and the timing relative to the expected response to systemic therapy.

Follow-up and post-treatment surveillance depend on subtype and the treatment received. In FDG-avid forms, response assessment with PET provides a standardized estimate of remission and guides subsequent decisions, integrated with CT and clinical evaluation. Monitoring should not focus only on recurrence but also on functional esophageal sequelae and late hematologic and cardiometabolic toxicities related to treatment.

In patients in remission after systemic therapy for aggressive disease, the first few years carry the highest risk and require periodic visits focused on recurrent dysphagia, retrosternal pain, weight loss, B symptoms and signs of anemia. Imaging is tailored to risk and clinical context, avoiding automatic repeated use in the absence of clinical indications, whereas endoscopy is reserved for suggestive symptoms, suspected complications or the need to assess stenosis and persistent ulceration.

In indolent forms, surveillance emphasizes clinical assessment, selected laboratory parameters and targeted imaging. Nutritional management and swallowing assessment remain constant priorities because dysmotility, scar stenosis or radiotherapy sequelae may persist even after an oncologic response. Integration among the hematologist, gastroenterologist, dietitian and radiation oncologist reduces the risk of underestimating sequelae that substantially affect quality of life.

Long-term quality-of-life considerations in primary esophageal lymphoma depend on the interaction among recovery of swallowing, treatment sequelae and the psychological burden of a cancer diagnosis. Even after complete remission, some patients retain nutritional vulnerability, fear of recurrence and a need for lasting dietary adaptations, particularly when disease was associated with marked stenosis or substantial weight loss.

After treatment, dysphagia may improve rapidly in forms that respond well to systemic therapy, but residual dysphagia, a sensation of obstruction, reflux or pain on swallowing may persist, particularly after radiotherapy or in the presence of pre-existing wall damage. Swallowing rehabilitation, individualized dietary management and monitoring for nutritional deficiencies are high-impact interventions because they influence independence, energy and return to work.

Late toxicities depend on the regimen and may include peripheral neuropathy, prolonged fatigue, infection risk during selected periods and, in some patients, cardiac sequelae after anthracyclines or endocrine and metabolic complications related to corticosteroids. Quality of life therefore requires follow-up that combines oncologic surveillance with prevention of late complications and clear communication about goals and clinical warning signs requiring prompt reassessment.

Complications of primary esophageal lymphoma result from local progression, dissemination and treatment effects. The most important functional complication is stenosis with severe dysphagia, which may cause dehydration, malnutrition and aspiration. Ulcerated lesions may cause bleeding and anemia. In advanced or rapidly progressive disease, perforation or fistulas to the trachea or bronchi may occur; these high-morbidity events require urgent and often multidisciplinary management.

When systemic dissemination is present, complications reflect disease burden and distant-organ involvement. Even without evident dissemination, tumor-associated inflammation and catabolism may accelerate sarcopenia and functional decline, particularly in older or already frail patients. Management of local complications must be integrated with antineoplastic treatment because symptom control is often a prerequisite for delivering causal therapy.

• Chemoimmunotherapy toxicity: myelosuppression, infections, mucositis, peripheral neuropathy and cardiotoxicity, requiring selected hematologic and cardiologic monitoring.
• Radiotherapy toxicity: acute esophagitis, worsening dysphagia, ulceration and late stenosis, with effects on nutrition and swallowing.
• Nutritional complications: weight loss, dehydration, protein-calorie deficiency and aspiration risk, indicating a need for early nutritional support.

Prevention and management are based on accurate staging, timely initiation of subtype-appropriate treatment, nutritional support and toxicity monitoring. In patients with complex disease or local complications, integrated supportive care and, when indicated, palliative care permit more effective symptom control and better continuity of care.