Management and Evaluation of Significant Café au Lait Spots

Initial Diagnostic Evaluation

• The National Institutes of Health (NIH) diagnostic criteria for neurofibromatosis type 1 (NF1) include having ≥6 café au lait macules (CALMs) with a size of ≥5mm prepubertal or ≥15mm postpubertal, which is associated with a reduced life expectancy of 8-15 years primarily due to malignant peripheral nerve sheath tumors and cardiovascular disease 1
• Documenting the exact number and size of all CALMs is crucial, as ≥6 spots meeting size criteria is one of the NIH diagnostic criteria for NF1 2
• Examine for axillary or inguinal freckling (Crowe's sign), which is highly specific for NF1 2
• Look for Lisch nodules on slit-lamp examination (iris hamartomas) 2
• Assess for cutaneous or subcutaneous neurofibromas 1

Distinguish NF1 from Other Conditions

• RASopathies (Noonan syndrome, Costello syndrome, CBL syndrome) present with CALMs plus dysmorphic facies, congenital heart defects, short stature, and cryptorchidism 3
• Legius syndrome (SPRED1 mutations) mimics NF1 with CALMs and freckling but lacks neurofibromas and optic gliomas 4

Referral and Genetic Testing

• Any patient meeting ≥2 NIH diagnostic criteria for NF1 should be referred to genetics 2, 5
• Diagnostic evaluation of parents when a child is newly diagnosed with NF1 is recommended 2
• Leukemia diagnosed at age <18 with café au lait macules and/or other signs of NF1 warrants referral to genetics 3
• Genetic testing can establish diagnosis and guide surveillance, though phenotypic severity varies even within families 2

Specialized NF1 Clinic Referral

• Strongly recommended for all confirmed or suspected NF1 cases for care coordination and surveillance 1
• NF1 requires lifelong monitoring for life-threatening complications including MPNST (risk 8.5% by age 30, 15.8% by age 85) 1

Surveillance Protocol for Confirmed NF1

• Complete physical examination focusing on new or changing neurofibromas, particularly rapid growth or severe pain suggesting MPNST transformation 1, 6
• Blood pressure measurement to screen for pheochromocytoma and renovascular hypertension 1, 7
• Neurologic examination for new deficits suggesting MPNST or CNS tumors 1
• Assessment for diaphoresis/palpitations (pheochromocytoma) 1, 6

Patient Education Priorities

• Progressive severe pain in existing neurofibroma (MPNST) requires urgent evaluation 1, 6
• Rapid change in tumor volume (MPNST) requires urgent evaluation 1, 6
• New unexplained neurologic symptoms (MPNST, brain tumors) require urgent evaluation 1, 6
• Diaphoresis, palpitations, or hypertensive episodes (pheochromocytoma) require urgent evaluation 1, 6

Common Pitfalls to Avoid

• Do not confuse Legius syndrome with NF1 - Legius patients have CALMs but lack tumor risks and require different surveillance 4
• Do not delay referral in children with CALMs plus other concerning features (developmental delays, hypotonia, leukemia) as these suggest syndromic diagnoses requiring specialized care 3, 8

Neurofibromatosis Prevalence and Characteristics

Epidemiology of Neurofibromatosis

• Neurofibromatosis type 1 (NF1) affects approximately 1 in 2,000-3,000 people worldwide, with no known variation in prevalence specific to the Philippines 9, 10
• NF1 is the most common type of neurofibromatosis, affecting 1 in 2,000-3,000 people worldwide, with no known variation in prevalence specific to the Philippines 9, 10
• NF2 is much rarer, affecting approximately 1 in 25,000-33,000 individuals globally 11
• There is no documented ethnic or geographical variation in NF1 prevalence that would suggest a different rate in the Philippines compared to global statistics 10

Clinical Characteristics

• Optic pathway gliomas occur in 15-20% of NF1 patients, typically in young children 9
• Plexiform neurofibromas are often congenital but grow during the first two decades of life 12

Clinical Impact and Mortality

• NF1 is associated with an 8-15 year reduction in average life expectancy, primarily due to malignant neoplasms and cardiovascular causes 10
• The risk of malignant peripheral nerve sheath tumors (MPNST) in NF1 patients is 8.5% by age 30, 12.3% by age 50, and 15.8% by age 85 10, 13
• High-grade MPNSTs are usually fatal and contribute significantly to NF1 mortality 10, 13

Diagnostic Approach and Management

• The American College of Medical Genetics and Genomics recommends evaluation by and care coordination with a specialized NF clinic 13
• Genetic testing can confirm diagnosis in uncertain cases 10
• Annual general medical evaluation is recommended, including assessment for signs of MPNST, pheochromocytoma, neuropathy, depression, and chronic pain 13
• Women with NF1 should begin annual mammograms at age 30 and consider breast MRI with contrast between ages 30-50 13
• Baseline MRI of known or suspected non-superficial plexiform neurofibromas should be considered 13
• Pregnant women with NF1 should be referred to a high-risk obstetrician 13

Neurofibromatosis Type 1 Management

Diagnostic Testing

• Genetic testing of the NF1 gene is indicated in specific scenarios, including diagnostic uncertainty, evaluation of parents when a child is newly diagnosed with NF1, detection of NF1 variant of uncertain significance, prenatal diagnosis, and preimplantation genetic diagnosis, as recommended by the American College of Medical Genetics and Genomics 14
• Prenatal diagnosis via amniocentesis or chorionic villus sampling for known familial mutations is an option for families with a history of NF1, as suggested by the National Society of Genetic Counselors 15

Management Approach

• All patients with confirmed or suspected NF1 should be referred to a specialized NF1 clinic for coordinated care, which significantly reduces morbidity and mortality, according to the American Academy of Pediatrics 16, 14
• Annual comprehensive evaluation, including history assessment and physical examination, is necessary for every adult with NF1 to monitor for potential complications, as recommended by the National Institutes of Health 16, 14

Malignancy Surveillance

• The cumulative risk of Malignant Peripheral Nerve Sheath Tumor (MPNST) is 8.5% by age 30, 12.3% by age 50, and 15.8% by age 85, highlighting the need for regular surveillance, as reported by the Children's Tumor Foundation 16, 14
• Annual mammography starting at age 30 and consideration of contrast-enhanced breast MRI between ages 30-50 are recommended for women with NF1, as suggested by the National Comprehensive Cancer Network 15, 17
• Routine biochemical or imaging screening for pheochromocytoma in asymptomatic NF1 patients is not recommended, but testing is indicated for hypertensive patients, pregnant patients, and those with paroxysmal hypertension, according to the Endocrine Society 18, 17

Pregnancy Management

• Referral to a high-risk obstetrician is recommended for women with NF1, and increased maternal morbidity, including gestational hypertension and preeclampsia, should be monitored, as suggested by the American College of Obstetricians and Gynecologists 15
• Genetic counseling should be provided, given the 50% offspring recurrence risk for autosomal dominant inheritance, as recommended by the National Society of Genetic Counselors 15

Additional Surveillance Considerations

• Vitamin D levels and supplementation, as well as dual-energy X-ray absorptiometry (DEXA), should be considered based on clinical presentation and age, as suggested by the American Academy of Pediatrics 15

Diagnostic Criteria for Neurofibromatosis Type 1 in Children

Clinical Presentations

• Children with café au lait macules (CALMs) and developmental delays, hypotonia, or neurologic symptoms are at high risk for biallelic mismatch repair deficiency syndrome or other genetic conditions, according to the American Academy of Pediatrics 19, 20
• The presence of CALMs with dysmorphic facial features, congenital heart defects, or short stature suggests RASopathies (Noonan, Costello, or CBL syndromes), as recommended by the American College of Medical Genetics and Genomics 21
• Children with 1-2 isolated CALMs in the absence of other features are considered low-risk for underlying genetic syndromes, as stated by the American Academy of Pediatrics 22

Diagnostic Distinctions

• Legius syndrome can be distinguished from neurofibromatosis type 1 (NF1) by the absence of neurofibromas, optic gliomas, and tumor risks, and genetic testing (SPRED1 vs. NF1 gene) can definitively distinguish these conditions, according to the National Institutes of Health 21
• Constitutional mismatch repair deficiency syndrome is suggested by the presence of CALMs plus childhood leukemia, brain tumors, or GI malignancies, which carries an extremely high cancer risk, as reported by the American Cancer Society 19, 20

Risk Stratification

• Children with CALMs plus developmental delays or hypotonia are considered high-risk and should be referred to genetics immediately, as recommended by the American Academy of Pediatrics 19, 20
• Children with multiple CALMs but no clear syndrome are considered intermediate-risk and should have close follow-up and consideration of genetics referral, according to the American College of Medical Genetics and Genomics 21
• Children with 1-2 isolated CALMs are considered low-risk and can be followed routinely, as stated by the American Academy of Pediatrics 22

Cancer Screening in Neurofibromatosis Type 1

Evidence-Based Screening Approach

• The American College of Medical Genetics and Genomics (ACMG) does not recommend routine CT abdomen/pelvis for cancer screening in neurofibromatosis type 1 (NF1) patients, instead emphasizing clinical surveillance through annual comprehensive physical examination as the cornerstone of cancer detection 23, 24, 25, 26
• Symptom-directed imaging rather than routine screening is the appropriate approach for NF1 patients, with MRI preferred over CT when imaging is indicated to minimize ionizing radiation exposure 23, 24
• For Malignant Peripheral Nerve Sheath Tumor (MPNST) surveillance, clinical suspicion drives imaging decisions, and targeted MRI of concerning plexiform neurofibromas is recommended when clinically indicated 24
• For pheochromocytoma surveillance, no routine biochemical or imaging screening is recommended for asymptomatic patients, but plasma free metanephrine testing is indicated for hypertensive patients or those with paroxysmal symptoms 23
• For breast cancer screening in women with NF1, annual mammography starting at age 30 years and consideration of contrast-enhanced breast MRI between ages 30-50 years are recommended 23, 27

Clinical Surveillance Protocol

• Annual physical examination should assess for new or rapidly growing neurofibromas, severe or progressive pain in existing neurofibromas, blood pressure measurement, and symptoms of pheochromocytoma 23, 24, 25, 26

When CT Abdomen/Pelvis IS Indicated

• CT or MRI abdomen/pelvis should be obtained in scenarios with positive biochemical testing for pheochromocytoma, clinical suspicion of MPNST, symptomatic presentation suggesting intra-abdominal pathology, or follow-up of known abdominal/pelvic neurofibromas with concerning changes 23, 24, 26

Important Caveats

• NF1 patients have increased cancer susceptibility, and cumulative radiation from repeated CT scans may increase malignancy risk, making MRI a preferred imaging modality 24, 27
• Whole-body MRI is emerging as a potential surveillance tool in specialized centers, but is not yet incorporated into standard guidelines and may detect asymptomatic tumors without clear improvement in outcomes 26

Differentiating NF-1, Legius Syndrome, and Benign Familial Café-au-Lait Macules

Clinical Features and Malignancy Risk

• The American College of Medical Genetics and Genomics recommends that NF-1 carries an 8-15 year reduction in life expectancy with significant malignancy risk, while both Legius syndrome and benign familial café-au-lait macules lack tumor risk and have normal life expectancy 28
• NF-1 is associated with cognitive and learning disabilities, which are frequently present, according to the National Institutes of Health 29
• The National Cancer Institute states that NF-1 has a high risk of malignant peripheral nerve sheath tumor (MPNST), with an 8.5% risk by age 30, 12.3% by age 50, and 15.8% by age 85 28
• The American Cancer Society recommends that women with NF-1 should undergo annual mammography starting at age 30, and consider breast MRI with contrast ages 30-50 29

Diagnostic Approach and Management

• The Genetics in Medicine journal suggests that any patient meeting ≥2 NIH diagnostic criteria for NF1 should undergo genetic testing, and parents of children newly diagnosed with NF1 should also be tested 28
• The Clinical Cancer Research journal recommends that patients with NF-1 should undergo annual comprehensive evaluation by a specialized NF1 clinic throughout life, with lifelong surveillance required due to ongoing malignancy risk 28
• The American Academy of Pediatrics states that children with NF-1 should be screened for learning disabilities and developmental delays, and receive developmental/educational support as needed 29

Special Considerations

• The Clinical Cancer Research journal notes that Constitutional Mismatch Repair Deficiency (CMMRD) can mimic NF1, with CALMs, axillary freckling, neurofibromas, and Lisch nodules in up to one-third of patients, and has a higher frequency of skin hypopigmentation, pilomatrixoma, and multiple developmental venous anomalies 30, 29
• The National Institutes of Health recommends that CMMRD should be suspected in cases of CALMs plus childhood leukemia, brain tumors, or GI malignancies, or CALMs plus developmental delays or hypotonia 30, 29

Constitutional Mismatch Repair Deficiency (CMMRD) – Cancer Risk and Referral Guidance

Cancer Risk Associated with CMMRD

• Children (and adolescents) who exhibit café‑au‑lait macules together with hypopigmented skin lesions, pilomatrixomas, and a personal history of childhood malignancies such as leukemia, brain tumors, or gastrointestinal cancers have an extremely high overall cancer risk. 31

Referral and Management Recommendations for Suspected CMMRD

• In any child with café‑au‑lait macules who also shows developmental delay, hypotonia, or a diagnosis of childhood leukemia, an immediate referral to a genetics specialist is advised to evaluate for CMMRD and initiate appropriate surveillance. 31