Noncardiogenic pulmonary edema as the chief manifestation of a pheochromocytoma: a case report of MEN 2A with pedigree analysis of the RET proto-oncogene.
Pheochromocytomas are rare neoplasias of the adrenal medulla which generally present with paroxysmal or sustained hypertension. Cardiogenic pulmonary edema is a common feature of these tumors, but few cases have been described with noncardiogenic pulmonary edema. We report a pheochromocytoma with the principle manifestation of noncardiogenic pulmonary edema and characterize a genetic lesion associated with the disorder. A 30-year-old man was admitted with abdominal pain and breathlessness. x-Ray examination of the chest revealed a massive, diffuse infiltration of the left lung without cardiomegaly. No paroxysmal blood pressure fluctuations or heart failure were evident during the entire course, and the infiltrate and dyspnea resolved in three days without inotropic or diuretic agents. Serum norepinephrine and epinephrine levels were elevated twenty and fifty times above normal, respectively. The patient was ultimately diagnosed with multiple endocrine neoplasia type 2A (MEN 2A). Mutations in the RET proto-oncogene have been described recently in patients with MEN 2A. Mutation analysis of selected RET exonic sequences identified a germline mutation at codon 634 in exon 11 of the RET proto-oncogene. The mutation introduces a transition encoding a non-conservative substitution from TGC (Cys) to CGC (Arg) and creates a novel restriction site recognized by HhaI. We further screened for this mutation among four of the proband's relatives by HhaI restriction analysis. One asymptomatic family member was identified who subsequently elected prophylactic total thyroid removal. Histological examination of this specimen confirmed the presence of medullary thyroid carcinoma.