Sunday, April 3, 2011

Pediatric Thyroid Cancer: Clinical Review

Thyroid carcinoma in pediatric patients usually manifests as an asymptomatic neck mass, with a reported incidence of cervical lymphadenopathy that ranges from 35-83%. The neck masses are typically discovered incidentally by parents, patients, or physicians during routine physical examination.

Focal fold paralysis in children with thyroid malignancy is much less common than in adults with thyroid malignancy. Niedziela and Korman (2002) studied 37 children in Poland with thyroid cancer, none of whom presented with vocal cord paralysis or associated hoarseness.

Additionally, unlike adults, young patients with thyroid nodules often do not report pain, tenderness, compression of the respiratory tract, problems with swallowing, or inappropriate fixation of the neck. Even young patients who have lung metastases usually do not report pulmonary symptoms. However, 10-20% of patients present with distant metastasis (most commonly to the lungs) and 70% of patients present with extensive regional nodal involvement.

Many young patients have a family history of thyroid cancer. For example, 25% of medullary thyroid cancer (MTC) cases are hereditary, while over 75% are sporadic. A family history of MTC, pheochromocytoma, or hyperparathyroidism may indicate multiple endocrine neoplasia 2A (MEN2A) or multiple endocrine neoplasia 2B (MEN2B), both of which are inherited in an autosomal dominant fashion.

All family members should be genetically screened for this mutation, especially given its autosomal dominant mode of inheritance. A history of Graves disease, hypothyroidism, or goiter should suggest a benign thyroid disease process, although long-term suppression of Graves Disease with antithyroid drugs may lead to increased risk of malignant thyroid transformation.

Clinical Facts Review

·      Pediatric thyroid carcinoma usually presents with one or more painless firm neck nodules.

·       Most malignant nodules detected in children were 1.5 cm or larger in size.  

·      A soft compressible nodule is less likely to be malignant than a firm one.

·  Tenderness of the nodule suggests hemorrhage into a nodule, a cyst, or an inflammatory process. For     instance, if the skin is warm, erythematous, and diffusely tender, a diagnosis of acute suppurative thyroiditis is most likely and an inflammatory workup should be pursued.

·  Fixation of the mass to surrounding tissues and vocal fold paralysis suggest malignancy, although this process is rare. Lymphadenopathy further increases the likelihood of malignancy.

·      Diffuse thyroid enlargement or multiple nodules are more suggestive of a benign process.

·     Mucosal neuromas of the tongue, palpebral conjunctiva, and lips with marfanoid body habitus may suggest MEN2B syndrome with medullary carcinoma, which often manifests in infancy.

Finally, patients who report a rapid growth rate of cancer may have a poorer prognosis, although that observation is controversial. Pain is rarely associated. Local tenderness is attributed to either thyroid cyst formation or hemorrhage into a rapidly growing nodule. Autoimmune disease, which often results in rapidly enlarging thyroid glands, confounds any associated glandular nodularity for which malignancy must be excluded.

Author: Mark E Gerber, MD, FACS, FAAP  Clinical Assistant Professor of Otolaryngology, University of Chicago, Pritzker School of Medicine; Section Head, Pediatric Otolaryngology-Head and Neck Surgery, NorthShore University HealthSystem 

Co-Author: Brian Kip Reilly, MD  Assistant Professor of Otolaryngology and Pediatrics, Department of Otolaryngology, Children's National Medical Center, George Washington University School of Medicine 

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