CASE SUMMARY:

A 37-year-old woman with an established personal and family history of Marfan's syndrome and a several-month history of severe headaches, chest pains, and palpitations presented with acute onset of severe chest pain radiating to her back. Physical exam confirmed Marfanoid body habitus and revealed extreme lability in blood pressure (ranging from 240/140 to 68/30), even after institution of an aggressive, intravenous antihypertensive regimen. Laboratory data are withheld. Initial imaging studies included CT of the chest and abdomen and MRI of the abdomen.

DIAGNOSIS:

Marfan's syndrome with aortic dissection complicated by pheochromocytoma and medullary carcinoma of the thyroid gland.

CT of the aorta confirmed a type B dissection beginning just distal to the origin of left subclavian artery and extending to the level of the aortic bifurcation (figure 1). There was no evidence of leakage or rupture. CT images through the upper abdomen revealed a mass that appeared to be invading or displacing the right lobe of the liver (figure 2). Most of the mass exhibited some degree of contrast enhancement, with low-attenuation areas posteriorly.

MRI evaluation of the mass demonstrated low signal on T1 with very high signal throughout most of the mass on T2-weighted images (figures 3 and 4). T2-weighted images also revealed areas of low signal posteriorly, with fluid-fluid levels indicating cyst formation, necrosis, and/or hemorrhage. The mass exhibited a mild degree of enhancement after gadolinium administration. Diagnostic considerations include hepatic masses, such as cavernous hemangioma, hemorrhagic adenoma, hepatocellular carcinoma, and metastasis, as well as adrenal masses, such as hemorrhagic adenoma, adrenal carcinoma, metastases, or pheochromocytoma. Serum and urine catecholamines subsequently were found to be quite elevated, and pheochromocytoma was confirmed after excising the mass (following preoperative prophylaxis with phenoxybenzamine).

Review of the chest CT revealed a low-attenuation lesion in the left lobe of the thyroid gland, and the serum calcitonin level was found to be elevated. Total thyroidectomy was performed, and medullary carcinoma confined to the left lobe of the thyroid gland was confirmed.

DISCUSSION:

This patient's triad of Marfanoid habitus (arachnodactyly, increased lower extremity-to-trunk ratio, and scoliosis), pheochromocytoma, and medullary carcinoma of the thyroid gland supports a diagnosis of multiple endocrine neoplasia type IIb. However, this patient did not exhibit the characteristic mucosal neuromas usually seen in this disorder. The MEN IIb syndrome usually is inherited as an autosomal dominant trait. The patient's parents exhibited no manifestations of the disease, but the patient's sister and two sons do exhibit Marfanoid body habitus. In Marfan's syndrome, aortic dissection and aneurysm are due to cystic medionecrosis, probably related to production of faulty elastin fibers. Other cardiovascular abnormalities associated with Marfan's syndrome include mitral valve prolapse, mitral regurgitation, and aortic root dilation with regurgitation.

Although the Marfanoid habitus is a relatively common phenotypic expression in MEN IIb, the cardiovascular manifestations of Marfan's syndrome, including aortic dissection as in this case, have not been described previously in MEN IIb.

Whatever the ultimate genetic explanation for the appearance of pheochromocytoma and aortic dissection in this patient, this combination of pathology provided an interesting diagnostic and therapeutic challenge. The tremendous blood pressure and cardiac output fluctuations associated with catecholamine release by the pheochromocytoma may have accelerated any preexisting weakness in the tunica media and perhaps led to premature dissection.

References

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