Internal Medicine

(Wang) #1

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)
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