Mesothelioma in Children & Young Adults

Mesothelioma in children and young adults is an exceedingly rare occurrence, with fewer than 2% of all malignant mesothelioma cases diagnosed in patients under the age of 40. Pediatric mesothelioma — diagnosed in patients under 18 — is even rarer, with only individual case reports and small series in the medical literature. This rarity creates significant challenges in diagnosis, treatment planning, and prognostic estimation, as there are no large-scale clinical trials or standardized protocols specific to young mesothelioma patients.¹

A distinguishing feature of mesothelioma in children and young adults is the frequent absence of a documented asbestos exposure history. While asbestos is the established cause of mesothelioma in the majority of adult cases, young patients often have no identifiable occupational or environmental asbestos exposure. Instead, genetic predisposition — particularly germline mutations in the BAP1 (BRCA1-associated protein 1) tumor suppressor gene — plays a more prominent role. BAP1 germline mutations have been identified in a significant proportion of young mesothelioma patients and are associated with a familial cancer syndrome that includes mesothelioma, uveal melanoma, and renal cell carcinoma.²

Peritoneal mesothelioma represents a higher proportion of cases in children and young adults compared to the adult population, where pleural mesothelioma dominates. The biology of pediatric and young adult mesothelioma appears to differ from adult disease, with a higher prevalence of epithelioid histology and generally more indolent behavior. These biological differences contribute to a generally better prognosis compared to adult mesothelioma.³

Despite the rarity of the disease in young patients, treatment remains essential and typically follows adult protocols adapted for the patient's age and health. Families of young mesothelioma patients should be aware of the potential for BAP1 testing and genetic counseling. Additionally, even in cases without clear occupational asbestos exposure, legal options for compensation may exist through environmental exposure claims, product liability cases, or trust fund filings.

Symptoms of mesothelioma in children and young adults are similar to those in adults and depend on the location of the tumor:

• Pleural mesothelioma — chest pain, shortness of breath, persistent cough, pleural effusion
• Peritoneal mesothelioma — abdominal pain, bloating, ascites, nausea, changes in bowel habits
• General symptoms — fatigue, unexplained weight loss, fever of unknown origin

Because mesothelioma is so rarely suspected in young patients, diagnosis is frequently delayed while more common conditions are investigated first.

The causes of mesothelioma in children and young adults differ from those in the adult population:

• BAP1 germline mutations — inherited mutations in the BAP1 tumor suppressor gene are the most commonly identified genetic risk factor in young mesothelioma patients
• Other genetic predispositions — mutations in NF2, CDKN2A, and other tumor suppressor genes may contribute
• Asbestos exposure — while less common than in adults, some young patients have environmental or secondhand asbestos exposure history
• Radiation exposure — prior therapeutic radiation, particularly to the chest or abdomen, has been implicated in rare cases
• Unknown etiology — in many cases, no identifiable cause can be determined

Risk factors for mesothelioma in children and young adults include:

• BAP1 germline mutation — family history of BAP1-associated cancers (mesothelioma, uveal melanoma, renal cell carcinoma)
• Family history of mesothelioma — multiple family members with mesothelioma suggests a genetic component
• Environmental asbestos exposure — living near naturally occurring asbestos deposits or contaminated sites
• Secondhand asbestos exposure — contact with asbestos-contaminated materials in the home
• Prior radiation therapy — especially to the chest or abdomen during childhood

Diagnosing mesothelioma in young patients presents unique challenges:

• High index of suspicion needed — mesothelioma is rarely considered in the differential diagnosis for young patients, leading to diagnostic delays
• Imaging — CT scan and MRI are used to evaluate the extent of disease
• Tissue biopsy — definitive diagnosis requires histopathological examination with immunohistochemical staining
• Genetic testing — BAP1 germline testing is recommended for all young mesothelioma patients
• Genetic counseling — families of patients with BAP1 mutations should be offered genetic counseling and surveillance

Treatment for mesothelioma in children and young adults generally follows adult protocols, adapted for age and overall health:

• Surgery — cytoreductive surgery is the primary treatment when feasible, particularly for peritoneal mesothelioma
• Chemotherapy — cisplatin-based regimens including cisplatin and pemetrexed
• HIPEC — heated intraperitoneal chemotherapy combined with surgery for peritoneal disease
• Immunotherapy — immune checkpoint inhibitors may be considered, particularly for unresectable disease
• Clinical trials — enrollment in clinical trials is strongly encouraged given the rarity of the disease in this population

Young patients generally tolerate aggressive multimodal therapy better than older adults, which contributes to their more favorable outcomes.³

The prognosis for mesothelioma in children and young adults is generally better than in older adults:

• Young patients tend to have better overall survival, likely due to better tolerance of aggressive treatment, higher prevalence of epithelioid histology, and different underlying tumor biology
• BAP1-associated mesothelioma, which is more common in young patients, has been linked to a more indolent disease course
• Peritoneal mesothelioma in young patients treated with surgery and HIPEC can have favorable long-term outcomes
• The absence of comorbidities typical of older adults allows more aggressive treatment approaches

Prevention strategies for mesothelioma in children and young adults focus on genetic awareness and exposure avoidance:

• Genetic testing for BAP1 mutations in families with a history of mesothelioma or related cancers
• Regular cancer surveillance for individuals with known BAP1 germline mutations
• Avoiding environmental asbestos exposure, particularly in areas with known naturally occurring asbestos
• Ensuring children are not exposed to asbestos through take-home contamination from family members' occupations