Internal Medicine

0521779407-14 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 21:16

Multiple Endocrine Neoplasia 2 1013

■MEN2B:

➣Mucosal neuromas on lips and tongue

➣Marfanoid habitus

MTC more often metastatic

tests

Laboratory

■Basic blood studies:

➣MTC: pentagastrin-stimulated calcitonin

➣Hyperparathryoidism: elevated calcium and intact PTH

■Basic urine studies:

➣Pheochromocytoma: 24-h urine for catecholamines and meta-

nephrines; plasma metanephrines and catecholamines; helpful

at time of symptoms

■Specific Diagnostic Tests

➣Index case diagnosis and screening done by genetic analysis

➣MEN2A and 2B due to mutations in RET tyrosine kinase proto-

oncogene; most common MEN2A mutations in exons 10 and 11;

MEN2B mutations at codon 918

➣Familial MTC (no other MEN2A tumors) mutations in exon 10

and 11

Imaging

■MTC: radioiodine not useful; sestimibi and 111 I-octreotide scanning

useful as adjunct to CT or MRI

■Pheochromocytoma: MRI useful; 131 I-MIBG nuclear scan less sen-

sitive but more specific than CT or MRI

■Hyperparathyoidism: sestimibi scan preoperatively and in recurrent

disease; US, MRI, CT adjunctive

■Thyroid Biopsy

➣FNA biopsy of thyroid nodule

differential diagnosis

■MTC with family history of MTC and MEN2 tumor points to diagnosis

■Sporadic, new mutations occur, so family history not obvious

■Familial MTC occurs without other MEN2 findings; 20% of all MTC

management

What to Do First

■Detailed medical and family history (identify index case; important

for screening)